<PAGE>
 
                                    NET LEASE
                                 (Build-to-Suit)

                             OPUS NORTHWEST, L.L.C.
                                    Landlord


                                       and

                     COMPUTER NETWORK TECHNOLOGY CORPORATION
                                     Tenant



                                     Dated:


                               September____, 1998
<PAGE>
 
                                TABLE OF CONTENTS

ARTICLE I TERM OF LEASE------------------------------------------------   2


      Section 1.1 Term of Lease.---------------------------------------   2

      Section 1.2  Option to Renew.------------------------------------   3

ARTICLE II CONSTRUCTION OF IMPROVEMENTS--------------------------------   3


      Section 2.1 Landlord's Improvements.-----------------------------   3

      Section 2.2 Tenant Improvements.---------------------------------   5

      Section 2.3 Excused Delay.---------------------------------------   8

      Section 2.4 Possession of Demised Premises.----------------------   8

      Section 2.5 Substantial Completion.------------------------------   9

      Section 2.6 Tenant's Acceptance of Demised Premises.-------------   9

      Section 2.7 Repair and Maintenance.------------------------------  10

      Section 2.8 Construction Guaranty.-------------------------------  10

      Section 2.9 Resolution of Construction-Related Disputes.---------  11

      Section 2.10  Millennium Compliant.------------------------------  12

      Section 2.11  Liquidated Damages.--------------------------------  12

ARTICLE III BASIC RENT-------------------------------------------------  13


      Section 3.1 Basic Rent.------------------------------------------  13

      Section 3.1A Determination of Basic Rent.------------------------  14

      Section 3.1B Rental Abatement.-----------------------------------  14

      Section 3.2 Basic Rent Adjustments.------------------------------  15

      Section 3.3 Additional Rent.-------------------------------------  17

      Section 3.4 Delinquent Payments.---------------------------------  17

      Section 3.5 Independent Obligations.-----------------------------  18

ARTICLE IV USE OF DEMISED PREMISES-------------------------------------  18


      Section 4.1 Permitted Use.---------------------------------------  18

      Section 4.2 Preservation of Demised Premises.--------------------  19

      Section 4.3 Acceptance of Demised Premises.----------------------  19

ARTICLE V PAYMENT OF TAXES AND ASSESSMENTS-----------------------------  20


      Section 5.1 Payment of Impositions.------------------------------  20

      Section 5.2 Tenant's Right to Contest Impositions.---------------  21

      Section 5.3 Levies and Other Taxes.------------------------------  22

                                       ii
<PAGE>
 
      Section 5.4 Evidence of Payment.---------------------------------  22

      Section 5.5 Escrow for Taxes and Assessments.--------------------  23

      Section 5.6 Landlord's Right to Contest Impositions.-------------  23

ARTICLE VI INSURANCE---------------------------------------------------  24


      Section 6.1 Tenant's Casualty Insurance Obligations.-------------  24

      Section 6.2 Tenant's Liability and Other Insurance Coverage.-----  25

      Section 6.3 Insurance Provisions.--------------------------------  26

      Section 6.4 Waiver of Subrogation.-------------------------------  26

      Section 6.5 Tenant's Personal Property Insurance.----------------  26

      Section 6.6 Unearned Premiums.-----------------------------------  27

      Section 6.7 Blanket Insurance Coverage.--------------------------  27

      Section 6.8 Failure of Tenant to Insure.-------------------------  27

ARTICLE VII UTILITIES--------------------------------------------------  28


      Section 7.1 Payment of Utilities.--------------------------------  28

      Section 7.2 Additional Charges.----------------------------------  28

ARTICLE VIII REPAIRS---------------------------------------------------  28


      Section 8.1 Tenant's Repairs.------------------------------------  28

      Section 8.2 Maintenance.-----------------------------------------  29

      Section 8.3 Tenant's Waiver of Claims Against Landlord.----------  30

      Section 8.4 Prohibition Against Waste.---------------------------  31

      Section 8.5 Landlord's Right to Effect Repairs.------------------  31

      Section 8.6 Misuse or Neglect.-----------------------------------  31

      Section 8.7 Landlord Repairs.------------------------------------  31

ARTICLE IX COMPLIANCE WITH LAWS AND ORDINANCES-------------------------  32


      Section 9.1 Compliance with Laws and Ordinances.-----------------  32
 
      Section 9.2 Compliance with Permitted Encumbrances.--------------  32
  
      Section 9.3 Tenant's Obligations.--------------------------------  33

      Section 9.4 Tenant's Right to Contest Laws and Ordinances.-------  33

      Section 9.5 Compliance with Hazardous Materials Laws.------------  34

      Section 9.6 Hazardous Material Representation by Landlord.-------  35

      Section 9.7 Cost of Compliance with Hazardous Materials Laws.----  36

      Section 9.8 Discovery of Hazardous Materials.--------------------  36

      Section 9.9 Indemnification.-------------------------------------  36

                                      iii
<PAGE>
 
      Section 9.10 Environmental Audits.-------------------------------  37

      Section 9.11 Acts or Omissions Regarding Hazardous Materials.----  37

      Section 9.12 ADA Requirements.-----------------------------------  37

      Section 9.13 Survival.-------------------------------------------  38

ARTICLE X MECHANIC'S LIENS AND OTHER LIENS-----------------------------  38


      Section 10.1 Freedom from Liens.---------------------------------  38

      Section 10.2 Landlord's Indemnification.-------------------------  39

      Section 10.3 Removal of Liens.-----------------------------------  39

ARTICLE XI INTENT OF PARTIES-------------------------------------------  40


      Section 11.1 Net Lease.------------------------------------------  40

      Section 11.2 Entry by Landlord.----------------------------------  40

      Section 11.3 Interest on Unpaid Amounts.-------------------------  41

ARTICLE XII DEFAULTS OF TENANT-----------------------------------------  42


      Section 12.1 Event of Default.-----------------------------------  42

      Section 12.2 Remain Out of Possession.---------------------------  43

      Section 12.3 Repossession Following Default.---------------------  44

      Section 12.3A Right to Re-enter.---------------------------------  44

      Section 12.3B Termination of Lease.------------------------------  44

      Section 12.4  Performance of Tenant Obligations.-----------------  44

      Section 12.5 Surrender of Demised Premises.----------------------  45

      Section 12.6 Reletting by Landlord.------------------------------  45

      Section 12.7 Survival of Tenant's Obligations.-------------------  45

      Section 12.7A Rent During Repossession and Re-letting.-----------  45

      Section 12.8 Expiration and Termination Damages.-----------------  46

      Section 12.9 No Waiver.------------------------------------------  47

      Section 12.10 Cumulative Remedies.-------------------------------  47

      Section 12.11 Waiver by Tenant.----------------------------------  48

ARTICLE XIII DESTRUCTION AND RESTORATION-------------------------------  48


      Section 13.1 Tenantable Within 180 Days.-------------------------  48

      Section 13.2 Not Tenantable Within 270 Days.---------------------  49

      Section 13.3 Demised Premises Substantially Damaged.-------------  49

      Section 13.4 Insufficient Proceeds.------------------------------  49

      Section 13.5 Landlord's Repair Obligations.----------------------  50

                                       iv
<PAGE>
 
      Section 13.6 Rent Apportionment.---------------------------------  50

ARTICLE XIV CONDEMNATION-----------------------------------------------  50


      Section 14.1 Condemnation of Entire Demised Premises.------------  50

      Section 14.2 Partial Condemnation/Termination of Lease.----------  51

      Section 14.3 Partial Condemnation/Continuation of Lease.---------  52

      Section 14.4 Continuance of Obligations.-------------------------  53

      Section 14.5 Adjustment of Rent.---------------------------------  53

ARTICLE XV ASSIGNMENT AND SUBLETTING-----------------------------------  53


      Section 15.1 Restriction on Transfer.----------------------------  53

      Section 15.2 Sublease Requirements.------------------------------  53

      Section 15.3  Sublessee Maintenance Requirements.----------------  54

      Section 15.4 Restriction From Further Assignment.----------------  55

      Section 15.5  Tenant's Failure to Comply.------------------------  55

      Section 15.6  Acquisition of Tenant.-----------------------------  55

ARTICLE XVI SUBORDINATION, NONDISTURBANCE, NOTICE TO MORTGAGEE 
      AND ATTORNMENT---------------------------------------------------  56


      Section 16.1 Subordination by Tenant.----------------------------  56

      Section 16.2 Landlord's Default.---------------------------------  56

      Section 16.3 Attornment.-----------------------------------------  57

ARTICLE XVII SIGNS-----------------------------------------------------  58


      Section 17.1 Tenant's Signs.-------------------------------------  58

ARTICLE XVIII REPORTS BY TENANT----------------------------------------  58


      Section 18.1 Annual Statements.----------------------------------  58

ARTICLE XIX CHANGES AND ALTERATIONS------------------------------------  58


      Section 19.1 Tenant's Changes and Alterations.-------------------  58

ARTICLE XX MISCELLANEOUS PROVISIONS------------------------------------  61


      Section 20.1 Entry by Landlord.----------------------------------  61

      Section 20.2 Exhibition of Demised Premises.---------------------  62

      Section 20.3 Indemnification by Tenant.--------------------------  62

      Section 20.4 Notices.--------------------------------------------  63

      Section 20.5 Quiet Enjoyment.------------------------------------  64

      Section 20.6 Landlord's Continuing Obligations.------------------  64

                                       v
<PAGE>
 
      Section 20.7 Estoppel.-------------------------------------------  65

      Section 20.8 Delivery of Corporate Documents.--------------------  66

      Section 20.9 Memorandum of Lease.--------------------------------  66

      Section 20.10 Severability.--------------------------------------  66

      Section 20.11 Successors and Assigns.----------------------------  66

      Section 20.12 Captions.------------------------------------------  67

      Section 20.13 Relationship of Parties.---------------------------  67

      Section 20.14 Entire Agreement.----------------------------------  67

      Section 20.15 No Merger.-----------------------------------------  67

      Section 20.16 Possession and Use.--------------------------------  67

      Section 20.17 No Surrender During Lease Term.--------------------  67

      Section 20.18 Surrender of Demised Premises.---------------------  68

      Section 20.19 Holding Over.--------------------------------------  68

      Section 20.20 Landlord Approvals.--------------------------------  69

      Section 20.21 Survival.------------------------------------------  69

      Section 20.22 Attorneys' Fees.-----------------------------------  69

      Section 20.23 Landlord's Limited Liability.----------------------  69

      Section 20.24 Broker.--------------------------------------------  70

      Section 20.25 Governing Law.-------------------------------------  70

      Section 20.26 "Intentionally Omitted. "--------------------------  70

      Section 20.27 Time is of the Essence.----------------------------  70

      Section 20.28 Limited Right of Set Off.--------------------------  70

      Section 20.29 Time Period for Claims.----------------------------  71

      Section 20.30 Crescent Ridge Space.------------------------------  71

      Section 20.31  Transfer By Landlord.-----------------------------  71

      ARTICLE XXI SATELLITE DISH---------------------------------------  72

      ARTICLE XXII TERMS OF OPTION TO RENEW----------------------------  73

      Section 22.1  Terms of Option to Renew.--------------------------  73

      Section 22.2 Exercise of Option to Renew.------------------------  74

ARTICLE XXIII TENANT'S OPTION TO EXPAND BUILDING-----------------------  76


      Section 23.1 Tenant's Option to Expand Building.-----------------  76

      Section 23.2  Design of Phase Two Improvements.------------------  79

      Section 23.3 Cost of Phase Two Improvements.---------------------  79

      Section 23.4 Payment for Phase Two Improvements.-----------------  80

                                       vi
<PAGE>
 
      Section 23.5 Completion of Phase Two Improvements.---------------  81

      Section 23.6 Tenant's Right to Inspect.--------------------------  82

      Section 23.7 Compliance with Plans and Specifications.-----------  82

      Section 23.8 Guaranty of Improvements.---------------------------  83

      Section 23.9 Acceptance of Phase Two Improvements.---------------  83

      Section 23.10 Basic Rent for Phase One Improvements During
                    Term Extension.------------------------------------  84

ARTICLE XXIV FIT PLAN ALLOWANCE----------------------------------------  84




                                      vii
<PAGE>
 
                                  DEFINED TERMS


ADA--------------------------------------------------------------------  37
Additional Rent--------------------------------------------------------  17
Affiliate--------------------------------------------------------------  72
Agency Directive-------------------------------------------------------  35
Alterations------------------------------------------------------------  59
Alterations Architect or Engineer--------------------------------------  59
Appraisal Request------------------------------------------------------  74
Assembly---------------------------------------------------------------  19

Basic Rent-------------------------------------------------------------  13
Building---------------------------------------------------------------   2

City-------------------------------------------------------------------   9
Commencement Date------------------------------------------------------   8
Construction Price-----------------------------------------------------  79
Consultant-------------------------------------------------------------   4
Cost of the Work-------------------------------------------------------6,89

Deficiency-------------------------------------------------------------  46
Demised Premises-------------------------------------------------------   2

Early Access-----------------------------------------------------------   8
Early Occupancy Period-------------------------------------------------   8
Equipment-------------------------------------------------------------- 104
Events of Default------------------------------------------------------  42
Excess-----------------------------------------------------------------   5
Excess Amount----------------------------------------------------------  15
Excused Delay----------------------------------------------------------   8
Expansion Amendment----------------------------------------------------  77
Expansion Notice-------------------------------------------------------  76
Experts----------------------------------------------------------------  75
Extended Coverage Endorsement------------------------------------------  24

FF & E-----------------------------------------------------------------   8
Field Labor Cost-------------------------------------------------------  90
Final Fit Plan---------------------------------------------------------   6
Final Plans and Specifications-----------------------------------------   3
Final Tenant Improvement Plans-----------------------------------------   6
Full Replacement Cost--------------------------------------------------  24

General Conditions-----------------------------------------------------   6

Hazardous Materials----------------------------------------------------  34
Hazardous Materials Laws-----------------------------------------------  34

Impositions------------------------------------------------------------  20
Improvements-----------------------------------------------------------   2
Indemnity Event--------------------------------------------------------  62
Indirect Lighting------------------------------------------------------  16
Initial Term-----------------------------------------------------------   2

Land-------------------------------------------------------------------   2
Landlord---------------------------------------------------------------   2
Landlord's Completion Estimate-----------------------------------------  77
Landlord's Improvements------------------------------------------------   3
Landlord Items---------------------------------------------------------  29
Landlord's and Tenant's Final Offer------------------------------------  74 
Lease------------------------------------------------------------------   2

Maintenance and Repair Report------------------------------------------  54
Market Rent------------------------------------------------------------  73
Maximum Rate of Interest-----------------------------------------------  17
Mortgage---------------------------------------------------------------  56
Moving Allowance-------------------------------------------------------  14
Moving Costs-----------------------------------------------------------  14

Outline Plans and Specifications---------------------------------------   3

Permitted Encumbrances-------------------------------------------------   2
Phase One Improvements-------------------------------------------------  76
Phase Two Basic Rent---------------------------------------------------  79
Phase Two Final Plans and Specifications-------------------------------  80
Phase Two Improvements-------------------------------------------------  76
Phase Two Outline Plans and Specifications-----------------------------  77
Phase Two Permits------------------------------------------------------  77
Preliminary Approvals--------------------------------------------------   5
Preliminary Fit Plan---------------------------------------------------   6
Proceedings------------------------------------------------------------  51
Project Supervisory Cost-----------------------------------------------  90
Punchlist Items--------------------------------------------------------   9

Renewal Term-----------------------------------------------------------   3
Renewal Terms----------------------------------------------------------   3
Rent-------------------------------------------------------------------  17
Request for Market Rent------------------------------------------------  74

Satellite Dish---------------------------------------------------------  72
Schematics-------------------------------------------------------------  76
Site Plan--------------------------------------------------------------  76
Structural Alteration--------------------------------------------------  59
Substantially Completed------------------------------------------------   9

T.I. Architect---------------------------------------------------------   6
Target Commencement Date-----------------------------------------------   9
Teachers---------------------------------------------------------------  85
Tenant-----------------------------------------------------------------   2
Tenant Improvement Allowance-------------------------------------------   5
Tenant Improvement Costs----------------------------------------------- 5,6
Tenant Improvements----------------------------------------------------   5
Term-------------------------------------------------------------------   3
Term Extension---------------------------------------------------------  78
Termination Date-------------------------------------------------------   3

Unacceptable Contractor List-------------------------------------------  79

Work-------------------------------------------------------------------  89

Y2K Provision----------------------------------------------------------  12

 

                                       1
<PAGE>
 
                                    NET LEASE

THIS NET LEASE (this "Lease"), is made this ___ day of September, 1998 by and
between OPUS NORTHWEST, L.L.C., a Delaware limited liability company, (the
"Landlord") and COMPUTER NETWORK TECHNOLOGY CORPORATION, a Minnesota
corporation, (the "Tenant").

                                   WITNESSETH:

     Landlord, for and in consideration of the rents, covenants and agreements
stated herein on the part of Tenant, its successors and assigns, to be paid,
kept, observed and performed, has leased, rented, let and demised, and by these
presents does lease, rent, let and demise unto Tenant, and Tenant does hereby
take and hire, upon and subject to the parties' obligations hereunder, all that
parcel of land situated in the City of Plymouth, County of Hennepin and State of
Minnesota, described in Exhibit "A" attached hereto and made a part hereof,
together with any appurtenant easements described in said Exhibit "A" (the
"Land"), together with all improvements located on and to be constructed
thereon. The "Landlord's Improvements" and the "Tenant's Improvements" (as those
terms are defined in Article II) and all other improvements, machinery,
equipment, fixtures and other property, real, personal or mixed (except Tenant's
trade fixtures) installed or located thereon by Landlord, together with all
additions, alterations and replacements thereof are hereinafter referred to as
the "Improvements." The Land and the Improvements are hereinafter referred to as
the "Demised Premises." The Demised Premises are subject to the easements,
restrictions, reservations and all other encumbrances now or hereafter recorded
against the Land all as set forth on Exhibit "E" (the "Permitted Encumbrances").
The structures to be located upon and being a part of the Demised Premises which
are constructed for human occupancy or for storage of goods, merchandise,
equipment, or other personal property are collectively called the "Building."


                                    ARTICLE I
                                  TERM OF LEASE

     SECTION 1.1 TERM OF LEASE.

     Except as otherwise provided in this Lease, the initial term of this Lease
(the "Initial Term") shall be for one hundred twenty six (126) full calendar
months (plus the beginning partial month, if any) commencing on the Commencement
Date (as defined in Section 2.4 hereof), and ending on the last day of the one
hundred and twenty sixth (126th) full calendar month after the Commencement Date
(the 

                                       2
<PAGE>
 
"Termination Date"). The "Term" of this Lease shall mean the Initial Term,
together with any "Renewal Terms" (as defined in Section 1.2 hereof) of this
Lease or any extensions to or modifications of the Initial Term.

     SECTION 1.2 OPTION TO RENEW.

     Tenant shall have the right, to be exercised as hereinafter provided, to
extend the Term of this Lease for two (2) extension periods (hereinafter,
collectively referred to as "Renewal Terms", or individually as "Renewal Term")
of five (5) years each, upon the terms and conditions and subject to the
limitations set forth in Article XXII herein.


                                   ARTICLE II
                          CONSTRUCTION OF IMPROVEMENTS

     SECTION 2.1 LANDLORD'S IMPROVEMENTS.

     Landlord agrees to furnish at Landlord's sole cost and expense all of the
material, labor, and equipment for the construction on the Land of the
improvements specified on the "Outline Plans and Specifications" which are
listed in Exhibit "B" attached hereto and made a part hereof (the "Landlord's
Improvements"). Landlord's Improvements shall be constructed in a good and
workmanlike manner in accordance with the "Final Plans and Specifications", as
the same are proposed by Landlord and approved by Tenant in substantial
accordance with this Lease and Landlord agrees to complete the construction
thereof in accordance with all applicable building codes as presently
interpreted and enforced by the governmental bodies having jurisdiction thereof;
provided, however, that reference is made to Article IX for specific provisions
dealing with "ADA" and "Hazardous Materials Laws." Landlord will use
commercially reasonable efforts to obtain a project "no-strike" provision from
the building trades council for the construction of the Improvements. Upon
"Substantial Completion" (as hereinafter defined), the Improvements will be fit
for human occupancy and use.

     Landlord agrees to prepare the Final Plans and Specifications so that they
are consistent with the Outline Plans and Specifications. Upon completion of
each phase of the Final Plans and Specifications, Landlord will submit the same
to Tenant for its approval. Tenant agrees that it will approve each such phase
provided that each such phase is consistent with the Outline Plans and
Specifications. Tenant shall approve or disapprove each phase of the Final Plans
and Specifications within ten (10) calendar days after receipt of same, and if
Tenant fails to approve or disapprove same within such ten (10) calendar day
period, Tenant shall be deemed to have approved such phase of the Final Plans
and Specifications. The Final Plans and Specifications shall be approved by
Landlord and Tenant by affixing thereon the signature or initials of (in the

                                       3
<PAGE>
 
case of the Landlord) an authorized officer or employee (and in the case of the
Tenant) an authorized officer of each of the respective parties hereto and a
complete description thereof (in the form of a schedule of drawings) shall be
attached to each parties' copy of this Lease and made a part hereof as Exhibit
"C". Such Exhibit "C" shall control the parties' obligations hereunder, except
as to nonconstruction matters contained in Exhibit "B", such as allowances and
exclusions not expressly and specifically superseded by Exhibit "C". The
signature of such authorized officer or employee shall be deemed conclusive
evidence of the approval indicated by such signature. Landlord agrees to appoint
competent personnel to work with Tenant in the preparation of the Final Plans
and Specifications for the Building and Tenant agrees to appoint an officer or
employee of Tenant to work with Landlord in the preparation of the Final Plans
and Specifications for the Building. Landlord and Tenant have initially
designated the individuals identified on Exhibit "C-1" as their respective
representative, although both parties reserve the right to change such
designation at will. Landlord acknowledges that Tenant has retained the services
of David Jackson as a construction consultant, (the "Consultant"); however, the
Consultant has not been given authority by the Tenant to make decisions on
behalf of the Tenant. Accordingly, while Landlord will allow the Consultant
access to the Demised Premises, Landlord will look directly to Tenant (and not
the Consultant) for the performance of all of Tenant's obligations hereunder.
Landlord shall have the authority to make changes required by any applicable
laws, codes, ordinances or regulations, as well as minor changes in the work to
be performed by it under this Lease and not inconsistent with the applicable
Outline Plans and Specifications or Final Plans and Specifications, as the case
may be.

     When Landlord requests Tenant to specify details or layouts with respect to
the Improvements, Tenant shall specify same, subject to the provisions of the
Outline Plans and Specifications, so as not to delay completion of the
Landlord's Improvements and, in any event, within five (5) business days of
request by Landlord. Tenant shall pay to Landlord all increased out-of-pocket
costs or actual damages incurred by Landlord attributable to Tenant's delays in
performing its obligations under this Article II. In the event that such delays
caused by Tenant result in the "Commencement Date" (as defined in Section 2.4)
being delayed, the parties acknowledge and agree that the Commencement Date
shall be deemed to occur on the date on which the Commencement Date would have
occurred but for such delay.

     Tenant and Landlord acknowledge that it is expected that all governmental
approvals and permits which Landlord believes are required in order for Landlord
to "Substantially Complete" (as defined in Section 2.5) the Landlord
Improvements and which are necessary to permit "Assembly" (as defined in Section
4.1) in at least 38,000 square feet of the Building (the "Permits") will be
issued by the appropriate governmental authorities by October 25, 1998. If any
of the Permits are not, despite Landlord's diligent pursuit thereof, received by
Landlord by October 25, 1998, the "Target Commencement Date" (as hereinafter
defined) shall be automatically extended day-for-day for each day after such
date until the day that the Permits are issued. Such 

                                       4
<PAGE>
 
delay in obtaining the Permits shall constitute "Excused Delay" (as hereinafter
defined). The Landlord expects to receive the following "Preliminary Approvals"
for the construction of the Improvements from the City of Plymouth on October 7,
1998: Site Plan approval, a Conditional Use Permit to exceed the height
restrictions of the City and to permit limited Assembly on the Demised Premises
and a Fire Lane Variance. In the event that, as of the conclusion of the City
Council meeting on October 7, 1998, the Preliminary Approvals have not been
obtained, then either party hereto may terminate this Lease on October 8, 1998
by delivering notice of such termination to the other party on or before 5:00
p.m. on October 8, 1998. In any event, the termination right herein provided for
shall, if not exercised as aforesaid, be deemed to be null and void and of no
further force and effect as of 5:00 p.m. on October 8, 1998.

     SECTION 2.2 TENANT IMPROVEMENTS.

     Landlord will furnish all of the material, labor and equipment for the
construction on the Demised Premises of the "Tenant Improvements" {as defined in
Section 2.2(a)}. The Tenant Improvements shall be constructed in a good a
workmanlike manner in substantial accordance with the "Final Tenant Improvement
Plans" {as defined in Section 2.2(c)}.

     (a) Landlord shall provide Tenant with a "Tenant Improvement Allowance" in
the amount of $4,573,125.00 for payment of the "Tenant Improvement Costs" {as
defined in Section 2.2(d)} incurred in constructing the "Tenant Improvements"
{as defined in this Section 2.2(a)}. The Tenant Improvement Allowance may not be
used to pay for Tenant's furniture, fixtures or equipment (other than weight
room equipment which is attached to the Improvements) and/or any Tenant
Improvements not approved by Landlord. The Tenant Improvement Allowance may also
be used to pay for the Proposed Kitchen Equipment identified on Exhibit "I" or
equipment performing the same function as the items on Exhibit I. The "Tenant
Improvements" are those Improvements identified in the "Final Tenant Improvement
Plans" (as hereinafter defined). The Tenant Improvement Allowance shall be used
by Landlord to pay for the Tenant Improvement Costs. In the event the Tenant
Improvement Costs exceed the Tenant Improvement Allowance (the "Excess"),
Landlord may require that Tenant provide Landlord with reasonable cash security
(as determined by Landlord in its sole discretion) to cover the amount of such
Excess. Tenant shall, in any event, pay the Excess to Landlord on or before the
Commencement Date. In the event the Tenant Improvement Cost is less than the
Tenant Improvement Allowance, then Tenant shall be entitled to a Basic Rent
adjustment as provided in Section 3.2 herein. Landlord shall be the general
contractor for all Tenant Improvement work. Except with respect to mechanical
and electrical work (which shall be provided by the same contractors performing
the Landlord's Improvements) and the carpentry and drywall work (which will be
performed by Landlord), all other major subcontractors will be competitively bid
by Landlord. 

                                       5
<PAGE>
 
     (b) Attached hereto as Exhibit "D" is a schedule of the drawings
constituting the preliminary fit plan for the Tenant Improvements to be
constructed by Landlord (the "Preliminary Fit Plan")which Preliminary Fit Plan
has been prepared by WCL Interiors, Inc., (the "T.I. Architect"). The
Preliminary Fit Plan has been approved by Tenant. The Tenant shall cause the
T.I. Architect to prepare a "Final Fit Plan" for the Tenant Improvements and
shall deliver the same to the Landlord for approval on or before October 5,
1998. The Final Fit Plan will be approved by the Landlord within fifteen (15)
business days after receipt of same so long as it is substantially similar to
the Preliminary Fit Plan. 

     (c) After Landlord's approval of the Final Fit Plan, the Tenant shall cause
the T.I. Architect to prepare final plans for the Tenant Improvements in
accordance with the Final Fit Plan and shall submit the same to Landlord for
approval on or before January 4, 1999. Landlord shall approve or disapprove the
final plans for the Tenant Improvements within fifteen (15) business days after
receipt of same, and if Landlord fails to approve or disapprove same within such
fifteen (15) business day period, Landlord shall be deemed to have approved such
final plans. The final plans for the Tenant Improvements which have been
prepared by the T.I. Architect and approved (or deemed approved) by Landlord are
hereinafter referred to as the "Final Tenant Improvement Plans". Landlord will
approve the Final Tenant Improvement Plans if they are substantially similar to
the Final Fit Plan, but Landlord will have no obligation to approve such final
Tenant Improvement Plans to the extent they are materially inconsistent with the
Final Fit Plan. Landlord's approval of the Final Tenant Improvement Plans will
not constitute a representation, warranty or agreement that such plans conform
to applicable building codes or professional design standards, Tenant having
agreed to look exclusively to the T.I. Architect for such assurances. In the
event, however, that Landlord has actual knowledge of a material inconsistency
between the Final Tenant Improvement Plans and the requirements of applicable
building codes, Landlord will advise Tenant of that inconsistency.

     (d) The price to be charged by Landlord to Tenant for the Tenant
Improvements (the "Tenant Improvement Costs") shall be the sum of the following
items: (i) the "Cost of the Work" (as hereinafter defined); plus (ii) Landlord's
actual "General Conditions" (as hereinafter defined) (not to exceed seven
percent (7%) of the Cost of the Work); plus (iii) three percent (3%) of the
amount referred to in subsection (i) for Landlord's overhead and profit in
connection therewith; plus (iv) any and all sales, transaction privilege and
other taxes on any of the foregoing which are not otherwise included on Schedule
B-1. The "Cost of the Work" shall mean all costs incurred by the Landlord in the
acquisition, construction or installation of the Tenant Improvements in the
categories identified on Exhibit "B-1". "General Conditions" shall include,
without limitation, the following costs associated with the Tenant Improvements:
project management costs (to the extent not otherwise included on Exhibit B-1),
superintendent, permits, plan and specification reproduction, job phone and
pager, storage, trash hauling and dumping, general cleanup, first aid safety,
small tools and expendable, final clean-up, insurance, field coordinator, site
services and miscellaneous equipment. The Tenant Improvements will be
constructed on an open 

                                       6
<PAGE>
 
book basis. Tenant will be permitted to review and audit, at its expense, the
Landlord's records with respect to the Tenant Improvement Costs. Those records
will include documents similar to the AIA Application and Certificate for
Payment which will allocate the Tenant Improvement Costs to the line items
identified on that Application. Such audit must be completed, if at all, within
one hundred and fifty (150) days of Substantial Completion. If Landlord agrees
with the result of that audit, the Tenant Improvement Cost charged to Tenant
shall be the Tenant Improvement Cost so determined pursuant to that audit. If
Landlord disagrees with such audit results, the parties will resolve such
disagreement pursuant to Section 2.9 hereof and, pending resolution of such
arbitration, the Tenant Improvement Cost charged to Tenant will be the amount
originally proposed by Landlord. Upon completion of such arbitration, the Tenant
Improvement Cost finally charged to Tenant will be the amount determined by
reason of such arbitration, with appropriate refunds or additional payments to
be made within fifteen (15) business days of the completion of the audit. Tenant
shall be responsible for Landlord's costs arising out of delays in completing
the Tenant Improvements caused by Tenant making revisions to the Final Tenant
Improvement Plans once they have been approved by the Landlord or arising out of
any other delay of Tenant in the performance of its obligations under Article
II. In the event Tenant orders any long lead time items that would delay
Substantial Completion of the Tenant Improvements, such delay shall be deemed a
delay by Tenant. "Long lead time items" shall mean items required to complete
the Tenant Improvements that may delay Substantial Completion due to causes such
as an extended length of time necessary for the supplier to manufacture same or
due to a lengthy shipping time. Landlord will advise Tenant if Landlord believes
Tenant has ordered long lead time items.

     If Tenant desires to make revisions to the Final Tenant Improvement Plans
after Tenant approves the Final Tenant Improvement Plans, Tenant will notify
Landlord of such proposed revisions. If Landlord approves the revisions, Tenant
will cause the T.I. Architect to revise the Final Tenant Improvement Plans
accordingly and will deliver the same to Landlord. Landlord will notify Tenant
of the resulting cost increase (or decrease) of Tenant's Improvements and the
anticipated delay in completing the Tenant's Improvements caused by such
revisions, if any. Tenant will approve or disapprove the increased cost and
delay within ten (10) business days after Landlord notifies Tenant of the
additional cost and delay. If Tenant fails to notify Landlord of its approval or
disapproval of the additional cost and delay within the ten (10) business day
period, Tenant will be deemed to have disapproved the additional cost or delay.
If Tenant disapproves, in writing, the additional cost or delay, Tenant will be
deemed to have withdrawn its proposed revisions to the Final Tenant Improvement
Plans. If the Tenant approves the additional cost and delay, then the Final
Tenant Improvement Plans (and the defined term "Tenant Improvements") will be
deemed amended to include the requested changes, and the Target Commencement
Date will be deemed adjusted by the delay occasioned by such revisions.

                                       7
<PAGE>
 
     SECTION 2.3 EXCUSED DELAY.

     Any delay which is caused or contributed to by act or failure to act of
Tenant or those acting for or under Tenant (including, without limitation,
delays in approval of plans and specifications or other material selections
beyond the time periods required hereby, delays in submission of the Final Fit
Plan or the Final Tenant Improvement Plans and delays occasioned by change
orders requested and approved by Tenant), labor disputes, casualties, acts of
God or the public enemy, governmental embargo restrictions, shortages of fuel,
labor, or building materials, action or non-action of public utilities, or of
local, state or federal governments affecting the work, or other causes beyond
Landlord's reasonable control, shall constitute "Excused Delay". Landlord shall
use commercially reasonable efforts to notify Tenant of an event of Excused
Delay within thirty (30) days of the occurrence of such an event.

     SECTION 2.4 POSSESSION OF DEMISED PREMISES.

     Except as herein provided (e.g. in cases of events of Excused Delay caused
by Tenant, its contractors, agents or employees), Tenant shall not be liable to
Landlord for the payment of Basic Rent or the payment of any other obligation to
be paid by Tenant under this Lease nor shall Tenant have any right to possession
or use of the Demised Premises until the date upon which the Landlord's
Improvements and the Tenant Improvements are "Substantially Completed" (as such
phrase is defined in Section 2.5 hereof). The date of Substantial Completion
shall be the "Commencement Date". If Tenant occupies any portion of the Demised
Premises prior to Substantial Completion, the terms of this Lease shall apply to
such occupancy or use of the Demised Premises by Tenant.

     Subject to the provisions of Section 3.1B with respect to Rental Abatement,
Basic Rent and the payment of other obligations to be paid by Tenant shall
commence on the date which is sixty one (61) days after the Commencement Date.
The failure of Tenant to take possession of or to occupy the Demised Premises
after the Commencement Date shall not serve to relieve Tenant of said
obligations or delay payments by Tenant to Landlord.

     Subject to this Section 2.4, Tenant, its consultants (including the
Consultant) may have access to the Demised Premises ("Early Access") for the
first sixty-one (61) days following the Commencement Date (the "Early Occupancy
Period") solely for the purpose of installing and testing its machinery,
equipment, fixtures and other personal property thereon (the "FF & E") and not
for the purpose of conducting its business therefrom or for any other purpose.
However, as a condition precedent to such right of access, Tenant shall first
meet with Landlord in order to establish reasonable arrangements for the
coordination between Landlord's work pursuant to this Lease and Tenant's
installation and testing work as aforesaid. Tenant shall contact Landlord to
arrange such a meeting, and Landlord shall cooperate with Tenant in 

                                       8
<PAGE>
 
regard thereto. Following such meeting and the establishment of such
coordination of work arrangements, Tenant shall have the aforesaid access, and
Landlord and Tenant shall cooperate with one another to permit such access. In
connection with any such access and installations by Tenant, Tenant shall not
interfere with the completion of construction or occasion any labor dispute as a
result of such installations. Tenant hereby agrees to assume all risk of loss or
damage to such FF & E, and to indemnify, defend and hold harmless Landlord from
any loss or damage to such FF & E, and all liability, loss or damage arising
from any injury to the property of Landlord, or its contractors, subcontractors
or materialmen, and any death or personal injury to any person or persons to the
extent proximately caused by such access or installations, except for liability,
loss or damage proximately caused by Landlord's gross negligence or intentional
acts. Further, if Tenant fails to request or delays a request for the required
coordination meeting, neither the Commencement Date nor Tenant's obligations to
pay Rent hereunder, shall be delayed.

     Anything in this Lease to the contrary notwithstanding other than Section
2.11, Landlord shall not be liable for any direct, indirect, special or
consequential damages resulting from any delay in Substantial Completion.

     SECTION 2.5 SUBSTANTIAL COMPLETION.

     Landlord shall diligently proceed with the construction of the Landlord's
Improvements and Tenant Improvements and, subject to Excused Delay,
"Substantially Complete" (as herein defined) the same and deliver possession
thereof to Tenant on or about October 1, 1999 (but not prior to October 1, 1999)
the "Target Commencement Date.".." The Landlord's Improvements and Tenant's
Improvements shall be considered "Substantially Completed" at such time as (a)
all such Improvements have been substantially completed in accordance with the
Final Plans and Specifications (and the Final Tenant Improvement Plans); (b) the
Landlord has certified that fact to Tenant; and (c) the Landlord has obtained a
permanent or temporary Certificate of Occupancy from the City of Plymouth (the
"City"), for the Demised Premises, provided, however, that if the City will not
issue the Certificate of Occupancy because the Tenant Improvements were not (in
the City's judgment) designed in compliance with applicable building codes, the
issuance of a Certificate of Occupancy will not be a requirement of Substantial
Completion. Within thirty (30) days following the Commencement Date, the parties
will execute an Amendment to this Lease confirming the Commencement Date.

     SECTION 2.6 TENANT'S ACCEPTANCE OF DEMISED PREMISES.

     At least five (5) days prior to the Commencement Date, but in any event
prior to the Tenant's right of Early Access, Landlord and Tenant shall agree
upon those items in the Improvements which are incomplete (the "Punchlist
Items"). Landlord shall immediately commence work on the Punchlist Items and
shall complete the same 

                                       9
<PAGE>
 
within sixty (60) days following agreement upon the Punchlist Items unless any
such Punchlist Items cannot reasonably be completed within such sixty (60) day
period, in which event Landlord shall commence to complete such Punchlist Items
during said sixty (60) day period and shall thereafter diligently and
continuously pursue same to completion. The acceptance of possession by Tenant
shall be deemed conclusively to establish that the Demised Premises, and all
Improvements, have been Substantially Completed, subject to any Punchlist Items;
provided, however, that Tenant may supplement the punch list by identifying
Punch List Items which Tenant establishes were deficiencies in the Improvements
as of the date of Substantial Completion, so long as such supplemental Punch
List Items are identified for Landlord within 120 days following Substantial
Completion. Landlord will complete said supplemental Punch List Items within
sixty (60) days, or such longer period as may be reasonably required.

     SECTION 2.7 REPAIR AND MAINTENANCE.

     Save and except for the one-year guaranty against defective items
occasioned by poor workmanship and/or materials referred to in Section 2.8, the
Punchlist Items referred to in Section 2.6, and the Landlord Items referred to
in Section 8.1, Tenant shall, from and after the Commencement Date, have and
hold the Demised Premises as the same shall then be without any liability or
obligation on the part of Landlord for making any alterations, improvements or
repairs of any kind in or about the Demised Premises for the Term of this Lease,
or any extension or renewal thereof, and Tenant agrees to maintain the Demised
Premises and all parts thereof in a good and sufficient state of repair as
required by the provisions of this Lease.

     SECTION 2.8 CONSTRUCTION GUARANTY.

     Landlord guarantees the Improvements against defective workmanship and/or
materials for a period of one year from the date of Substantial Completion. The
foregoing guaranty will not extend to matters governed by the "Y2K Provision"
(as defined in Section 2.10). Landlord agrees, at its sole cost and expense, to
repair or replace any defective item occasioned by poor workmanship and/or
materials during said one-year period. Performance of such one-year guaranty
shall be Landlord's sole and exclusive obligation with respect to defective
workmanship and/or materials, and Tenant's rights to enforce such one-year
guaranty shall be Tenant's sole and exclusive remedy against Landlord with
respect to such defective workmanship and/or materials in limitation of any
contract, warranty or other rights, whether express or implied, that Tenant may
otherwise have under applicable law.

     Upon expiration of the one year guaranty of Landlord, Landlord will assign
to Tenant, without recourse, any unexpired warranties received by Landlord from
subcontractor or materialmen. Landlord will cooperate, at Tenant's expense, in
Tenant's enforcement of any such warranties. Landlord will obtain a twenty (20)
year manufacturer's warranty on the roof membrane. Other warranties with a term
in 

                                       10
<PAGE>
 
excess of one (1) year which are to be obtained by Landlord are identified on
Exhibit "F" (the "Warranties").

     SECTION 2.9 RESOLUTION OF CONSTRUCTION-RELATED DISPUTES.

     In the event of any dispute pertaining directly to the parties' respective
obligations under this Article II, such dispute shall be submitted to binding
arbitration in accordance with the following provisions; provided, however, that
prior to submission to arbitration, representative of the Landlord and the
Tenant, with full settlement authority, will be required to meet on at least two
occasions, with appropriate consultants or other advisors, and shall make a good
faith effort to resolve any such dispute; provided further, that if such
meetings do not occur within thirty (30) days of demand by one of the parties,
or if such meetings do occur and the dispute is not resolved , the arbitration
shall nonetheless proceed. All delays occasioned by such arbitration shall
constitute Excused Delay.

     (a) Qualification of Arbitrators. In each case where it shall become
necessary to resort to arbitration, all arbitrators appointed by or on behalf of
either party or appointed pursuant to the provisions of this Section 2.8 (i) at
the time of their appointment, shall have not less than ten (10) years of
experience as developers or contractors of facilities substantially similar to
the Improvements which are the subject to the dispute; (ii) at the time of their
appointment, shall be devoting all or substantially all of their professional
time to such development or contracting activities; and (iii) shall in all
respects be impartial and disinterested with regard to the subject dispute.

     (b) Selection of Arbitrators: Procedures. The party desiring the
arbitration shall give written notice to that effect to the other party,
specifying in such notice the name, address and professional qualifications of
the person which such party has designated to act as an arbitrator. Within
twenty (20) days after the delivery of such notice, the other party shall give
written notice to the party desiring the arbitration, specifying the name,
address and professional qualifications of the person which such other party has
designated to act as an arbitrator. The dispute shall then promptly be presented
to such two (2) arbitrators for resolution. If such two (2) arbitrators cannot
agree on a resolution of the dispute within thirty (30) days after the delivery
of the notice appointing the second arbitrator, then such two (2) arbitrators
shall select a third arbitrator within the next ten (10) days. The dispute shall
then promptly be presented to all three (3) arbitrators, and the arbitrators'
decision (being the decision of a majority to them) shall be given within thirty
(30) days after the selection of the third arbitrator. Each party shall pay the
fees and expenses of the arbitrator designated by it, and the fees and expenses
of the third arbitrator shall be borne equally by both parties. If the party
receiving a request for arbitration (i.e., the other party from the party
desiring the arbitration) fails to appoint an arbitrator within the time period
specified above, or if the two (2) arbitrators so selected cannot agree on a
third arbitrator within the time period specified above, then either party, on
behalf of 

                                       11
<PAGE>
 
both parties, may request such designation or appointment by application to the
chief judge of the state trial court in the county and state in which the
Demised Premises are located, upon ten (10) days' prior written notice to the
other party. The arbitrators shall have all rights and powers conferred by the
Uniform Arbitration Act of the state in which the Demised Premises are located
and, except as otherwise provided herein, the arbitration proceedings shall be
carried on and governed by such Act.

     SECTION 2.10 MILLENNIUM COMPLIANT.

     Landlord will use commercially reasonable efforts to cause its
subcontractors for elevator, fire and life safety, energy management and HVAC to
include, in their subcontracts, provisions substantially the same as the
provisions contained in Exhibit "H" (the "Y2K Provision"). Landlord will have no
liability for any claimed failure of any portion of the Improvements to comply
with the Y2K Provision nor will Landlord have liability for failure to obtain
such provision in its various subcontracts. The Landlord's Guaranty, set forth
in Section 2.8, will not extend to matters addressed in the Y2K Provision.
Landlord will assign any claim it may have against its subcontractors for
claimed violation of the Y2K Provision to the Tenant.

     SECTION 2.11 LIQUIDATED DAMAGES.

     In the event that Substantial Completion has not occurred by October 1,
1999 (as that date is extended by reason of Excused Delay), then, as Tenant's
sole and exclusive remedy, the Tenant will receive the following additional Rent
Abatements as liquidated damages.

     2.11.1 The Basic Rent abatement period which is set forth in Subsection
     3.1(B) (a) and the Additional Rent abatement period which is set forth in
     Subsection 3.1(B) (b) and (c) will be extended by the number of days
     calculated in Subsection 2.11.2, below.

     2.11.2 The number of days of additional Rent abatement (as contemplated in
     Subsection 2.11.1) will be calculated as follows:

          (i) The "Delay Period" will be the number of days commencing on
          October 1, 1999 and continuing until the day before the date of
          Substantial Completion;

          (ii) The number of days of Excused Delay will be subtracted from the
          Delay Period;

          (iii) The number of days during the period resulting from the
          calculation in (ii) above during which the Demised Premises may
          reasonably be used by the Tenant for the purposes contemplated by the

                                       12
<PAGE>
 
          Early Access provisions of Section 2.4 (and provided Tenant has been
          given at least five (5) days notice of such fact) will be subtracted
          from the period resulting from the calculation in (ii) above. The
          resulting number of days will be the number of days by which the Base
          Rent and Additional Rent abatement period will be extended, as set
          forth in Subsection 2.11.1

                 
                                   ARTICLE III
                                   BASIC RENT

     SECTION 3.1 BASIC RENT.

     In consideration of the leasing of the Demised Premises and the
construction of the Landlord's Improvements and Tenant Improvements referred to
in Article II hereof, Tenant covenants to pay Landlord, without previous demand
therefor and without any right of setoff or deduction whatsoever, at the office
of Landlord at:

                              Until January 1, 1999:
                              ----------------------
                              Opus Northwest, L.L.C.
                              700 Opus Center
                              9900 Bren Road East
                              Minnetonka, MN  55343

                              After January 1, 1999
                              ---------------------
                              Opus Northwest, L.L.C.
                              10350 Bren Road West
                              Minnetonka, MN  55343


or at such other place as Landlord may from time to time designate in writing,
an annual rental for the Term of this Lease, sometimes herein referred to as
"Basic Rent". The Basic Rent hereunder shall be in addition to all Additional
Rent and any and all other charges for which Tenant is obligated hereunder, and
shall be as set forth in Section 3.1A hereof.

     SECTION 3.1A DETERMINATION OF BASIC RENT.

     (a) From the sixty second (62nd) day following the Commencement Date
through and including the date preceding the sixty-seventh (67th) month
following the Commencement Date, an annual Basic Rent in the amount of Two
Million Forty Eight Thousand Seven Hundred Sixty and 00/100 Dollars
($2,048,760.00) per year, payable monthly, in advance, in equal installments of
One Hundred Seventy Thousand Seven Hundred Thirty and 00/100 Dollars
($170,730.00); and

                                       13
<PAGE>
 
     (b) Commencing on the first day of the sixty-seventh (67th) month following
the Commencement Date and continuing through the balance of the Initial Term
hereof, an annual Basic Rent in the amount of Two Million Three Hundred Four
Thousand Eight Hundred Fifty Five and 00/100 Dollars ($2,304,855.00) per year,
payable monthly, in advance, in equal installments of One Hundred Ninety Two
Thousand Seventy One and 25/100 Dollars ($192,071.25).

     If the Term of this Lease does not commence on the first day of a calendar
month or end on the last day of a calendar month, the installment of Basic Rent
for the partial calendar month at the commencement or the termination of the
Term shall be prorated on the basis of the number of days of the Term within
such calendar month.

     SECTION 3.1B RENTAL ABATEMENT.

     Notwithstanding the terms of the foregoing Sections 3.1 and 3.1A, and
provided that there is no uncured Event of Default hereunder, (a) there shall be
no Basic Rent due for the period commencing on the date which is sixty one (61)
days following the Commencement Date through and including the one hundred
eighty third (183rd) day following the Commencement Date; (b) there shall be no
real estate taxes or installments of special assessments due for the period
commencing on the Commencement Date and continuing for sixty-one (61) days
thereafter; and (c) there shall be no Impositions (as such term is defined in
Section 5.1 herein), due for the period commencing on the date which is sixty
one (61) days following the Commencement Date and continuing until the one
hundred fifty third (153rd) day following the Commencement Date. Furthermore,
and notwithstanding the provisions of this Lease to the contrary, Landlord will
pay the costs of insurance required hereby allocable to the time period
described in (b) above and Landlord will pay the costs, if any, of any third
party management agreement (in an amount not to exceed the amount proposed to be
charged by Normandale Properties, Inc. for the management of the Demised
Premises pursuant to that certain proposal dated August 25, 1998), and property
service agreements entered into by Tenant which are allocable to that time
period.

     SECTION 3.2 BASIC RENT ADJUSTMENTS.

     Landlord and Tenant hereby acknowledge that Tenant is to receive (a) the
benefit of the Tenant Improvement Allowance and (b) a "Moving Allowance" (the
"Moving Allowance") not to exceed $914,625.00 for actual, reasonable costs
directly related to the following: (i) Tenant's physical move from its existing
facilities to the Demised Premises; (ii) telephone and computer cabling and
connections in the Demised Premises; and (iii) consulting fees, architectural,
design and engineering fees relating to the Demised Premises. The aforementioned
costs shall hereinafter be referred to as the "Moving Costs". Provided that
there is no uncured Event of Default hereunder, the Moving Allowance shall be
paid to Tenant within fifteen (15) days after the later of: (i) the Commencement
Date, and (ii) Landlord's receipt of full and final waivers of 

                                       14
<PAGE>
 
liens and contractors affidavits and statements, in such form as may be
reasonably required by Landlord, from all parties performing labor or supplying
materials or services for which Tenant is requesting reimbursement and showing
that all of such parties have been compensated. In connection therewith, Tenant
shall submit to Landlord a detailed breakdown of all of the costs for which
Tenant is seeking reimbursement, together with such evidence of payment as is
reasonably satisfactory to Landlord. If the Moving Costs exceed the Moving
Allowance, Tenant shall have sole responsibility for the payment of such excess
amount. If the Moving Costs are less than the Moving Allowance, Tenant shall not
be entitled to any payment, credit or abatement of Basic Rent for such
difference. Notwithstanding anything contained herein to the contrary, Tenant
shall forfeit its right to payment of any portion of the Moving Allowance which
has not been requested by Tenant (with appropriate documentation, as specified
above) on or before the 150th day following the Commencement Date.

     In the event Tenant does not utilize the entire Tenant Improvement
Allowance to pay for the Tenant Improvements, then the annual Basic Rent for
each full year of the Initial Term hereof shall be reduced by the product of
0.105 multiplied by the lesser of : (i) the unused portion of the Tenant
Improvement Allowance or (ii) the sum of $548,775.00. The foregoing reduction to
annual Basic Rent shall be prorated for any partial year based upon the ratio
that the number of days in such partial year bears to 365. Once the parties have
ascertained the foregoing reduction to Basic Rent, if any, Landlord shall
prepare and the parties shall execute an amendment to this Lease memorializing
the reduction to Basic Rent, as aforesaid. If the unused portion of the Tenant
Improvement Allowance exceeds $548,775.00, then such excess unused amount (not
to exceed $365,850.00) (the "Excess Amount") shall be available to Tenant for
use in making future alterations and improvements to the Demised Premises as set
forth herein. The Excess Amount shall be made available to Tenant from time to
time for the purposes of making future alterations and improvements to the
Demised Premises for a period of twenty (20) months following the Commencement
Date. Any portion of the Excess Amount which has not been utilized by Tenant as
set forth herein by the expiration of twenty (20) months following the
Commencement Date shall be deemed forfeited by Tenant and shall no longer be
available to Tenant. The Excess Amount shall only be made available to Tenant
for reimbursement for the Tenant's actual, reasonable expenditures for
architectural costs and expenses associated with alterations and improvements,
and for the actual, reasonable expenditures for attached and permanent leasehold
improvements within the Demised Premises. The Excess Amount shall not be
available for payment of any costs not enumerated in the preceding sentence or
for the cost of any fixtures, equipment, inventory or personal property.

     Tenant may make up to four (4) requests (but no more frequently than one
request per calendar quarter) for payment of all or any portion of the Excess
Amount provided Tenant must furnish Landlord with full and final waivers of
liens and contractors' affidavits or statements, in such form as may be required
by Landlord, 

                                       15
<PAGE>
 
showing that all of the said parties have been compensated in full and waiving
all liens in connection with the Demised Premises. Tenant shall submit to
Landlord a detailed breakdown of Tenant's total construction costs, together
with such evidence of payment as is reasonably satisfactory to Landlord.
Landlord shall pay the requested portion of the Excess Amount within thirty (30)
days of receipt of request thereof, provided that Tenant has provided the
information required herein. All such alterations and improvements to the
Demised Premises must be performed in accordance with all of the terms and
conditions of this Lease, including, without limitation, the terms of Article
XIX herein.

     In addition to the adjustment to the Basic Rent, if any, provided for in
the second paragraph of this Section 3.2, there shall be an additional
adjustment to annual Basic Rent in the event: (i) Tenant elects to modify the
specifications with respect to the "Indirect Lighting" (as defined in Section
6102-Lighting of the Outline Plans And Specifications); and (ii) such
modification results in a change in the cost of the Indirect Lighting so that
the premium cost of the Indirect Lighting above the base building parabolic
lighting as finally installed is other than $577,500.00. In the event Tenant
requests a modification to these specifications, Landlord shall calculate the
increased cost or savings resulting from such modification, and the annual Basic
Rent for each full year of the Initial Term hereof shall be adjusted by the
product of the increased cost, or the savings, as the case may be, multiplied by
0.105. The foregoing increase or reduction (as the case may be) to annual Basic
Rent shall be prorated for any partial year based upon the ratio that the number
of days in such partial year bears to 365.1

     If the Tenant elects to reduce the area of the Building using Indirect
Lighting to less than 150,000 square feet, Landlord will provide standard
parabolic lighting to that portion of the 150,000 square feet not covered by
Indirect Lighting, all at no additional cost to Tenant. Once Landlord has
calculated the increase or decrease in Basic Rent, as aforesaid, Landlord shall
prepare and the parties shall execute an amendment to this Lease memorializing
such increase or decrease.

     SECTION 3.3 ADDITIONAL RENT.

     The Basic Rent shall be absolutely net to Landlord so that this Lease shall
yield, net to Landlord, the Basic Rent specified in Section 3.1A in each year of
the Term of this Lease and that all Impositions, insurance premiums, utility
charges, maintenance, repair and replacement expenses (other than those required
hereunder to be paid by Landlord), payments or charges under covenants,
conditions and restrictions now or hereafter of record, all expenses relating to
compliance with laws, and all other costs, 

--------
1 For example, if the change in the Indirect Lighting specifications results in
a $50,000.00 cost savings, then the annual Basic Rent will be reduced by
$5,250.00 (being the product of (i) $50,000.00 multiplied by (ii) 0.105). If the
change in the Indirect Lighting specifications results in a $50,000.00 cost
increase, then the annual basic rent will be increased by $5,250.00 (being the
product of (i) $50,000.00 multiplied by (ii) 0.105.

                                       16
<PAGE>
 
fees, charges, expenses, reimbursements and obligations of every kind and nature
whatsoever relating to the Demised Premises (excepting only Landlord's portion
of the proration of real estate taxes and special assessments for the first and
last years of the Term of this Lease referred to in Section 5.1 and certain
taxes of Landlord referred to in the last sentence of Section 5.3 of this Lease)
which may arise or become due during the Term or by reason of events occurring
during the Term shall be paid or discharged by Tenant, at Tenant's sole cost and
expense. The obligations of the parties with respect to the payment for the
costs related to Landlord Items is controlled by Section 8.7 and not by the
immediately preceding sentence. In the event Tenant fails to pay or discharge
any imposition, insurance premium, utility charge, maintenance repair or
replacement expense which it is obligated to pay or discharge, Landlord may, but
shall not be obligated to pay the same, and in that event Tenant shall
immediately reimburse Landlord therefor and pay the same as additional rent (all
charges payable by Tenant other than Basic Rent, however denoted, are
hereinafter collectively referred to as "Additional Rent"), and Tenant hereby
agrees to indemnify, defend and save Landlord harmless from and against such
impositions, insurance premiums, utility charges, maintenance, repair and
replacement expenses, all expenses relating to compliance with laws, and all
other costs, fees, charges, expenses, reimbursements and obligations referred to
above. Basic Rent and Additional Rent are sometimes hereinafter collectively
referred to as "Rent".

     SECTION 3.4 DELINQUENT PAYMENTS.

     All payments of Basic Rent and Additional Rent shall be payable without
previous demand therefor and without any right of setoff or deduction
whatsoever, and in case of nonpayment of any item of Additional Rent by Tenant
when the same is due, Landlord shall have, in addition to all its other rights
and remedies, all of the rights and remedies available to Landlord under the
provisions of this Lease or by law in the case of nonpayment of Basic Rent. The
performance and observance by Tenant of all the terms, covenants, conditions and
agreements to be performed or observed by Tenant hereunder shall be performed
and observed by Tenant at Tenant's sole cost and expense. Any installment of
Basic Rent or Additional Rent or any other charges payable by Tenant under the
provisions hereof which shall not be paid when due or within ten days thereafter
shall bear interest at an annual rate equal to five percentage points per annum
in excess of the published "prime rate" or "base rate" of interest charged by
Norwest Bank Minnesota, NA (or similar institution if said Bank shall cease to
exist or to publish such a prime rate) from the date when the same is due
hereunder until the same shall be paid, but in no event in excess of the maximum
lawful rate permitted to be charged by Landlord against Tenant. Said rate of
interest is sometimes hereinafter referred to as the "Maximum Rate of Interest".

     In addition, any installment of Basic Rent or Additional Rent or any other
charges payable by Tenant under the provisions hereof which shall not be paid
when due and which remain unpaid ten days thereafter shall be subject to a late
payment fee 

                                       17
<PAGE>
 
of four percent (4%) of the unpaid amount. Tenant acknowledges that Tenant's
failure to pay Basic Rent or Additional Rent when due may cause Landlord to
incur unanticipated costs. The exact amount of such costs are impractical or
extremely difficult to ascertain. The parties agree that the late charge
specified above represents a fair and reasonable estimate of the costs Landlord
will incur by reason of such late payment and acceptance of such late charge
does not constitute a waiver of Tenant's default or limit any other remedy of
Landlord. The late charge shall be deemed to be Additional Rent and the right to
require it shall be in addition to all of Landlord's rights and remedies
hereunder or at law.

     SECTION 3.5 INDEPENDENT OBLIGATIONS.

     Any Term or provision of this Lease to the contrary notwithstanding, the
covenants and obligations of Tenant to pay Basic Rent and Additional Rent
hereunder shall be independent from any obligations, warranties or
representations, express or implied, if any, of Landlord herein contained.

                                       18
<PAGE>
 
                                   ARTICLE IV
                             USE OF DEMISED PREMISES

     SECTION 4.1 PERMITTED USE.

     The Demised Premises shall be used for office, storage, assembly
("Assembly") and accessory uses only, and for no other use without Landlord's
consent. Notwithstanding anything contained in this Lease to the contrary, in no
event shall more than 38,000 square feet of the Building be devoted to Assembly.
Tenant shall not use or occupy the same, or permit them to be used or occupied,
contrary to any statute, rule, order, ordinance, requirement or regulation
applicable thereto, or in any manner which would violate any certificate of
occupancy affecting the same, or which would make void or voidable any insurance
then in force with respect thereto or which would make it impossible to obtain
fire or other insurance thereon required to be furnished hereunder by Tenant, or
which would cause structural injury to the improvements or cause the value or
usefulness of the Demised Premises, or any portion thereof, substantially to
diminish (reasonable wear and tear excepted), or which would constitute a public
or private nuisance or waste or would violate any Hazardous Materials Laws (as
defined in Section 9.5), and Tenant agrees that it will promptly, upon discovery
of any such use, take all necessary steps to compel the discontinuance of such
use.

     SECTION 4.2 PRESERVATION OF DEMISED PREMISES.

     Tenant shall not use, suffer, or permit the Demised Premises, or any
portion thereof, to be used by Tenant, any third party or the public in such
manner as might, in Landlord's reasonable judgment, to impair Landlord's title
to the Demised Premises, or any portion thereof, or in such manner as might, in
Landlord's reasonable judgment, make possible a claim or claims of adverse usage
or adverse possession by the public, as such, or third persons, or of implied
dedication of the Demised Premises, or any portion thereof. Nothing in this
Lease contained and no action or inaction by Landlord shall mean that Landlord
has granted to Tenant any right, power or permission to do any act or make any
agreement that may create, or give rise to or be the foundation for any such
right, title, interest, lien, charge or other encumbrance upon the estate of
Landlord in the Demised Premises.

     SECTION 4.3 ACCEPTANCE OF DEMISED PREMISES.

     Tenant acknowledges that neither Landlord nor any agent of Landlord has
made any representation or warranty with respect to the Demised Premises or the
Building or with respect to the suitability or fitness of either for the conduct
of Tenant's business or 

                                       19
<PAGE>
 
for any other purpose and, subject to Landlord's obligations set forth in
Sections 2.1, 2.7 and 2.8 above, Tenant accepts the Demised Premises in the
condition thereof on the Commencement Date. Tenant shall comply with any
recorded covenants, conditions and restrictions affecting the Demised Premises
and the Building as of the commencement of the Lease or which, following
Tenant's approval thereof, are recorded during the Term of this Lease.


                                   ARTICLE V
                        PAYMENT OF TAXES AND ASSESSMENTS

     SECTION 5.1 PAYMENT OF IMPOSITIONS.

     Tenant covenants and agrees that, subject to Tenant's right to contest the
same under Section 5.2, it will pay during the Term, as Additional Rent, before
any fine, penalty, interest or cost may be added thereto for the nonpayment
thereof, all real estate taxes, special assessments (including installments of
currently levied assessments which are payable during the Term), water rates and
charges, sewer rates and charges, including any sum or sums payable for present
or future sewer or water capacity, charges for public utilities, street
lighting, excise levies, licenses, permits, inspection fees, other governmental
charges, payments or charges under covenants, conditions and restrictions now or
hereafter of record, and all other charges of whatsoever kind and nature
(including costs, fees, and expenses of complying with any restrictive covenants
or similar agreements to which the Demised Premises are, as of the date hereof,
subject) incurred in the use, occupancy, ownership, operation, leasing or
possession of the Demised Premises, without particularizing by any known name or
by whatever name hereafter called, and whether any of the foregoing be general
or special, ordinary or extraordinary, foreseen or unforeseen (all of which are
sometimes herein referred to as "Impositions"), which at any time during the
Term may have been or may be assessed, levied, confirmed, imposed upon, or
become a lien on the Demised Premises, or any portion thereof, or any
appurtenance thereto, rents or income therefrom, and such easements or rights as
may now or hereafter be appurtenant or appertain to the use of the Demised
Premises. Impositions will not include any sum included in the Cost of the Work,
as identified on Exhibit "B-1".

     Tenant shall pay all special (or similar) assessments for public
improvements or benefits which are currently levied or are levied or become a
lien on the Demised Premises during the Term; provided, however, that if by law
any special assessment is payable (without default) or, at the option of
Landlord, may be paid (without default) in installments (whether or not interest
shall accrue on the unpaid balance of such special assessment), Tenant may pay
the same, together with any interest accrued on the unpaid balance of such
special assessment, in installments as the same respectively become payable and
before any fine, penalty, interest or cost may be added thereto for the
nonpayment of any such installment and the interest thereon. Tenant shall pay
all 

                                       20
<PAGE>
 
special assessments or installments thereof (including interest accrued
thereon), whether heretofore or hereafter laid, assessed, levied or imposed upon
the Demised Premises, or any portion thereof, which are due and payable during
the Term. Landlord shall pay all installments of special assessments (including
interest accrued on the unpaid balance) which are due and payable prior to the
Commencement Date and after the Termination Date. Tenant shall pay all real
estate taxes, whether heretofore or hereafter levied or assessed upon the
Demised Premises, or any portion thereof, which are due and payable during the
Term. Landlord shall pay all real estate taxes which are due and payable prior
to the Commencement Date. Notwithstanding the foregoing, Landlord shall pay that
portion of the real estate taxes and installments of special assessments due and
payable in respect to the Demised Premises during the year the Term commences
and the year in which the Term ends which the number of days in said year not
within the Term bears to three hundred sixty-five (365), and Tenant shall pay
the balance of said real estate taxes and installments of special assessments
during said years.

     SECTION 5.2 TENANT'S RIGHT TO CONTEST IMPOSITIONS.

     Tenant shall have the right, at its own expense, to contest the amount or
validity, in whole or in part, of any Imposition by appropriate proceedings
diligently conducted, but only after payment of such Imposition (or provision of
security therefor) reasonably acceptable to Landlord, unless such payment, or a
payment thereof under protest, would operate as a bar to such contest or
interfere materially with the prosecution thereof, in which event,
notwithstanding the provisions of Section 5.1 hereof, Tenant may postpone or
defer payment of such Imposition if (a) neither the Demised Premises nor any
portion thereof would, by reason of such postponement or deferment, be in danger
of being forfeited or lost, and (b) Tenant shall have deposited with Landlord
cash or a certificate of deposit or other security acceptable to Landlord in the
amount of the Imposition so contested and unpaid, together with all interest and
penalties which may accrue, in Landlord's reasonable judgment, in connection
therewith, and all charges that may or might be assessed against or become a
charge on the Demised Premises, or any portion thereof, during the pendency of
such proceedings. If, during the continuance of such proceedings, Landlord
shall, from time to time, reasonably deem the amount deposited, as aforesaid,
insufficient, Tenant shall, upon demand of Landlord, make additional deposits of
such additional sums of money or such additional certificates of deposit as
Landlord may reasonably request. Upon failure of Tenant to make such additional
deposits, the amount theretofore deposited may be applied by Landlord to the
payment, removal and discharge of such Imposition, and the interest, fines and
penalties in connection therewith, and any costs, fees (including attorneys'
fees) and other liability (including costs incurred by Landlord) accruing in any
such proceedings.

     Upon the termination of any such proceedings, Tenant shall pay the amount
of such Imposition or part thereof, if any, as finally determined in such
proceedings, the 

                                       21
<PAGE>
 
payment of which may have been deferred during the prosecution of such
proceedings, together with any costs, fees, including attorneys' fees, interest,
penalties, fines and other liability in connection therewith, and upon such
payment Landlord shall return all amounts or certificates deposited with it with
respect to the contest of such Imposition, as aforesaid, or, at the written
direction of Tenant, Landlord shall make such payment out of the funds on
deposit with Landlord and the balance, if any, shall be returned to Tenant.

     Tenant shall be entitled to the refund of any Imposition, penalty, fine and
interest thereon received by Landlord which have been paid by Tenant or which
have been paid by Landlord but for which Landlord has been previously reimbursed
in full by Tenant. Landlord shall not be required to join in any proceedings
referred to in this Section 5.2 unless the provisions of any law, rule or
regulation at the time in effect shall require that such proceedings be brought
by or in the name of Landlord, in which event Landlord shall join in such
proceedings or permit the same to be brought in Landlord's name upon compliance
with such conditions as Landlord may reasonably require. Landlord shall not
ultimately be subject to any liability for the payment of any fees, including
attorneys' fees, costs and expenses in connection with such proceedings
(referred to in this Section 5.2). Tenant agrees to pay all such fees, costs and
expenses or, on demand, to make reimbursement to Landlord for such payment.
During the time when any such certificate of deposit or other security is on
deposit with Landlord, and prior to the time when the same is returned to Tenant
or applied against the payment, removal or discharge of Impositions, as above
provided, Tenant shall be entitled to receive all interest paid thereon, if any.
If the deposit held by Landlord can be placed in an interest bearing account,
Landlord will do so.

     SECTION 5.3 LEVIES AND OTHER TAXES.

     If, at any time during the Term of this Lease, any method of taxation shall
be such that there shall be levied, assessed or imposed on Landlord, or on the
Basic Rent or Additional Rent, or on the Demised Premises or on the value of the
Demised Premises, or any portion thereof, a capital levy, sales or use tax,
gross receipts tax, transaction privilege tax, rent tax or other tax on the
rents received therefrom, or a franchise tax, or an assessment, levy or charge
measured by or based in whole or in part upon such rents or value, Tenant
covenants to pay and discharge the same, it being the intention of the parties
hereto that the rent to be paid hereunder shall be paid to Landlord absolutely
net without deduction or charge of any nature whatsoever foreseeable or
unforeseeable, ordinary or extraordinary, or of any nature, kind or description,
except as in this Lease otherwise expressly provided. Nothing in this Lease
contained shall require Tenant to pay any municipal, state or federal net income
or excess profits taxes assessed against Landlord, or any municipal, state or
federal capital levy, estate, succession, inheritance or transfer taxes of
Landlord, or corporation franchise taxes imposed upon any corporate owner of the
fee of the Demised Premises.

                                       22
<PAGE>
 
     SECTION 5.4 EVIDENCE OF PAYMENT.

     Tenant covenants to furnish Landlord, within thirty (30) days after the
date upon which any Imposition or other tax, assessment, levy or charge is
payable by Tenant, official receipts of the appropriate taxing authority, or
other appropriate proof reasonably satisfactory to Landlord, evidencing the
payment of the same. The certificate, advice or bill of the appropriate official
designated by law to make or issue the same or to receive payment of any
Imposition or other tax, assessment, levy or charge may be relied upon by
Landlord as sufficient evidence that such Imposition or other tax, assessment,
levy or charge is due and unpaid at the time of the making or issuance of such
certificate, advice or bill.

     SECTION 5.5 ESCROW FOR TAXES AND ASSESSMENTS.

     At Landlord's written demand, Tenant shall pay to Landlord the known or
estimated yearly real estate taxes and assessments payable with respect to the
Demised Premises in monthly payments equal to one-twelfth of the known or
estimated yearly real estate taxes and assessments next payable with respect to
the Demised Premises. From time to time Landlord may re-estimate the amount of
real estate taxes and assessments, and in such event Landlord shall notify
Tenant, in writing, of such re-estimate and fix future monthly installments for
the remaining period prior to the next tax and assessment due date in an amount
sufficient to pay the re-estimated amount over the balance of such period after
giving credit for payments made by Tenant on the previous estimate. If the total
monthly payments made by Tenant pursuant to this Section 5.5 shall exceed the
amount of payments necessary for said taxes and assessments, such excess shall
be credited on subsequent monthly payments of the same nature; but if the total
of such monthly payments so made under this paragraph shall be insufficient to
pay such taxes and assessments when due, then Tenant shall pay to Landlord upon
demand such amount as may be necessary to make up the deficiency. Payment by
Tenant of real estate taxes and assessments under this Section 5.5 shall be
considered as performance of such obligation under the provisions of Section 5.1
hereof. Landlord agrees not to request such monthly deposits from Tenant so long
as both of the following conditions are true: (i) Tenant has not defaulted in
its obligation to timely pay Rent hereunder; and (ii) Landlord's mortgage lender
does not require Landlord to make such monthly deposits. If such monthly
deposits are required by Landlord because Landlord's mortgage lender has
required Landlord to make such monthly deposits, then Landlord will use
commercially reasonable efforts to obtain agreement from said mortgage lender to
hold said monthly deposits in an interest bearing account. In such event, all
interest earned on said monthly deposits will be credited to Tenant.

     SECTION 5.6 LANDLORD'S RIGHT TO CONTEST IMPOSITIONS.

                                       23
<PAGE>
 
     In addition to the right of Tenant under Section 5.2 to contest the amount
or validity of Impositions, Landlord shall also have the right, but not the
obligation, to contest the amount or validity, in whole or in part, of any
Impositions not contested by Tenant, by appropriate proceedings conducted in the
name of Landlord or in the name of Landlord and Tenant. If Landlord elects to
contest the amount or validity, in whole or in part, of any Impositions, such
contests by Landlord shall be at Landlord's expense, provided, however, that if
the amounts payable by Tenant for Impositions are reduced (or if a proposed
increase in such amounts is avoided or reduced) by reason of Landlord's contest
of Impositions, Tenant shall reimburse Landlord for costs incurred by Landlord
in contesting Impositions, but such reimbursements shall not be in excess of the
amount saved by Tenant by reason of Landlord's actions in contesting such
Impositions.

                                   ARTICLE VI
                                    INSURANCE

     SECTION 6.1 TENANT'S CASUALTY INSURANCE OBLIGATIONS.

     Tenant, at its sole cost and expense, shall obtain and continuously
maintain in full force and effect during the Term, commencing upon the earlier
of the Commencement Date or the date Tenant first enters the Demised Premises to
conduct any work, policies of insurance covering the Improvements (other than
insurance on Tenant's personal property which shall be maintained by Tenant as
provided for in Section 6.5 herein) constructed, installed or located on the
Demised Premises naming the Landlord and any additional parties designated by
Landlord, as additional insureds and/or loss payees (as specified by Landlord),
against (a) loss or damage by fire; (b) loss or damage from such other risks or
hazards now or hereafter embraced by an "Extended Coverage Endorsement",
including, but not limited to, windstorm, hail, explosion, vandalism, riot and
civil commotion, damage from vehicles, smoke damage, water damage and debris
removal; (c) loss for flood if the Demised Premises is in a designated flood or
flood insurance area or is in a flood prone area; (d) loss for damage by
earthquake; (e) loss from so-called explosion, collapse and underground hazards;
and (f) loss or damage from such other risks or hazards of a similar or
dissimilar nature which are now or may hereafter be customarily insured against
with respect to improvements similar in construction, design, general location,
use and occupancy to the Improvements. At all times, such insurance coverage
shall be in an amount equal to one hundred percent (100%) of the then "full
replacement cost" of the Improvements. "Full Replacement Cost" shall be
interpreted to mean the cost of replacing the Improvements without deduction for
depreciation or wear and tear, and it shall include a reasonable sum for
architectural, engineering, legal, administrative and supervisory fees connected
with the restoration or replacement of the Improvements in the event of damage
thereto or destruction thereof. If a sprinkler system shall be located in the
Improvements, sprinkler leakage insurance shall be procured and continuously
maintained by Tenant at Tenant's sole cost and expense. For the period 

                                       24
<PAGE>
 
prior to the Commencement Date, Landlord, at its sole cost and expense, shall
maintain in full force and effect, on a completed value basis, insurance
coverage on the Building on builder's risk or other comparable coverage, as well
as workers' compensation insurance as required by law. All insurance obtained
and maintained by Tenant pursuant to this Article VI shall at all times be
subject only to such deductible amounts as may be reasonably acceptable to
Landlord from time to time. Landlord acknowledges that a deductible of Ten
Thousand and 00/100 Dollars ($10,000.00) per occurrence is currently acceptable,
provided that Landlord retains the right to stipulate different deductibles from
time to time in Landlord's reasonable discretion.

     SECTION 6.2 TENANT'S LIABILITY AND OTHER INSURANCE COVERAGE.

     Tenant, at its sole cost and expense, shall obtain and continuously
maintain in full force and effect the following insurance coverage commencing on
the earlier of the Commencement Date or the date Tenant first enters the Demised
Premises to conduct any work:

     (a)  Comprehensive general liability insurance against any loss, liability
          or damage on, about or relating to the Demised Premises, or any
          portion thereof, with limits of not less than Five Million Dollars
          ($5,000,000.00) combined single limit, per occurrence and aggregate,
          coverage on an occurrence basis. Any such insurance obtained and
          maintained by Tenant shall name Landlord and any additional parties
          designated by Landlord as additional insureds therein and shall be
          obtained and maintained from and with a reputable and financially
          sound insurance company authorized to issue such insurance in the
          state in which the Demised Premises are located and reasonably
          satisfactory to Landlord. Such insurance shall specifically insure (by
          contractual liability endorsement) Tenant's indemnification
          obligations provided in this Lease, including, without limitation,
          those under Section 20.3.

     (b)  Boiler and pressure vessel (including, but not limited to, pressure
          pipes, steam pipes and condensation return pipes) insurance, provided
          the Building contains a boiler or other pressure vessel or pressure
          pipes. Landlord and any additional parties designated by Landlord
          shall be named as additional insureds in such policy or policies of
          insurance.

     (c)  Such other insurance and in such amounts as may from time to time be
          reasonably required by Landlord, against other insurable hazards which
          at the time are commonly insured against in the case of similar
          premises and/or buildings or improvements in the Twin Cities area.

     The insurance set forth in this Section 6.2 shall be maintained by Tenant
at not less than the limits set forth herein until reasonably required to be
changed from time to 

                                       25
<PAGE>
 
time by Landlord, in writing, whereupon Tenant covenants to obtain and maintain
thereafter such protection in the amount or amounts so required by Landlord.

     SECTION 6.3 INSURANCE PROVISIONS.

     All policies of insurance required by Section 6.1 shall provide that the
proceeds thereof shall be payable exclusively to Landlord as loss payee and if
Landlord so requests shall also be payable to any contract purchaser of the
Demised Premises and the holder of any mortgages now or hereafter becoming a
lien on the fee of the Demised Premises, or any portion thereof, as the interest
of such purchaser or holder appears pursuant to a standard named insured or
mortgagee clause. Tenant shall not, on Tenant's own initiative or pursuant to
request or requirement of any third party, take out separate insurance
concurrent in form or contributing in the event of loss with that required in
Section 6.1 hereof.

     Each policy required under this Article VI (or the certificate provided to
Landlord with respect to such policy) shall have attached thereto (a) an
endorsement that such policy shall not be canceled or materially changed without
at least thirty (30) days prior written notice to Landlord, and (b) an
endorsement to the effect that the insurance as to the interest of Landlord
shall not be invalidated by any act or neglect of Landlord or Tenant. All
policies of insurance shall be written in companies reasonably satisfactory to
Landlord and licensed in the state in which the Demised Premises are located.
Such certificates of insurance shall be in a form reasonably acceptable to
Landlord, shall be delivered to Landlord upon the earlier of the Commencement
Date or the date Tenant first enters the Demised Premises to conduct any work
and prior to expiration of such policy new certificates of insurance shall be
delivered to Landlord not less than 15 days prior to the expiration of the then
current policy term.

     SECTION 6.4 WAIVER OF SUBROGATION.

     Tenant shall cause to be inserted in the policy or policies of insurance
required by this Article VI hereof (other than any automobile and workers'
compensation policies), a so called "Waiver of Subrogation Clause" as to
Landlord. Tenant hereby waives, releases and discharges Landlord, its agents and
employees from all claims whatsoever arising out of loss, claim, expense or
damage or destruction covered or coverable by insurance required under this
Article VI, notwithstanding that such loss, claim, expense or damage may have
been caused by Landlord, its agents or employees, and Tenant agrees to look to
the insurance coverage only in the event of such loss.

     SECTION 6.5 TENANT'S PERSONAL PROPERTY INSURANCE.

     Tenant shall maintain insurance coverage (including loss of use and
business interruption coverage) upon Tenant's business and upon all personal
property of Tenant or the personal property of others kept, stored or maintained
on the Demised Premises 

                                       26
<PAGE>
 
against loss or damage by fire, windstorm or other casualties or causes for such
amount as Tenant may desire, and Tenant agrees that such policies (other than
any automobile and workers' compensation policies) shall contain a waiver of
subrogation clause as to Landlord.

     SECTION 6.6 UNEARNED PREMIUMS.

     Upon expiration of the Term of this Lease, the unearned premiums upon any
insurance policies or certificates thereof lodged with Landlord by Tenant shall,
provided that Tenant has complied with all of the terms and conditions of
Article XIII herein, as applicable, be payable to Tenant, provided that Tenant
shall not then be in default in keeping, observing or performing the terms and
conditions of this Lease.

     SECTION 6.7 BLANKET INSURANCE COVERAGE.

     Nothing in this Article shall prevent Tenant from taking out insurance of
the kind and in the amount provided for under the preceding paragraphs of this
Article under a blanket insurance policy or policies (certificates thereof
reasonably satisfactory to Landlord shall be delivered to Landlord) which may
cover other properties owned or operated by Tenant as well as the Demised
Premises; provided, however, that any such policy of blanket insurance of the
kind provided for shall (a) specify therein the amounts thereof exclusively
allocated to the Demised Premises or Tenant shall furnish Landlord and the
holder of any fee mortgage with a written statement from the insurers under such
policies specifying the amounts of the total insurance exclusively allocated to
the Demised Premises, and (b) not contain any clause which would result in the
insured thereunder being required to carry any insurance with respect to the
property covered thereby in an amount not less than any specific percentage of
the Full Replacement Cost of such property in order to prevent the insured
therein named from becoming a co-insurer of any loss with the insurer under such
policy; and further provided, however, that such policies of blanket insurance
shall, as respects the Demised Premises, contain the various provisions required
of such an insurance policy by the foregoing provisions of this Article VI.

     SECTION 6.8 FAILURE OF TENANT TO INSURE.

     Notwithstanding any contrary language in this Lease, if Tenant fails to
provide Landlord with evidence of insurance required hereby, Landlord may, but
is not obligated to, without further demand upon Tenant and without waiving or
releasing Tenant from any obligation contained in this Lease, obtain such
insurance. In such event, Tenant will pay to Landlord, as Additional Rent, all
expenses Landlord incurs obtaining such insurance. No such payment by Landlord
relieves Tenant from any default under this Lease.

                                       27
<PAGE>
 
                                   ARTICLE VII
                                    UTILITIES

     SECTION 7.1 PAYMENT OF UTILITIES.

     Tenant will pay, when due, all charges of every nature, kind or description
for utilities furnished to the Demised Premises after the Commencement Date, or
chargeable against the Demised Premises, including all charges for water,
sewage, heat, gas, light, garbage, electricity, telephone, steam, power or other
public or private utility services.

     SECTION 7.2 ADDITIONAL CHARGES.

     In the event that any charge or fee is required after the Commencement Date
by the state in which the Demised Premises are located, or by any agency,
subdivision or instrumentality thereof, or by any utility company furnishing
services or utilities to the Demised Premises, as a condition precedent to
furnishing or continuing to furnish utilities or services to the Demised
Premises, such charge or fee shall be deemed to be a utility charge payable by
Tenant. The provisions of this Section 7.2 shall include, but not be limited to,
any charges or fees for present or future water or sewer capacity to serve the
Demised Premises, any charges for the underground installation of gas or other
utilities or services, and other charges relating to the extension of or change
in the facilities necessary to provide the Demised Premises with adequate
utility services. In the event that Landlord has paid any such charge or fee
after the date hereof, Tenant shall reimburse Landlord for such utility charge.
If any such charge paid by Tenant is in the nature of a deposit with respect to
the payment of future charges, Landlord will cooperate with Tenant's effort to
obtain a refund of that deposit following the termination of the Term of this
Lease.


                                  ARTICLE VIII
                                     REPAIRS

     SECTION 8.1 TENANT'S REPAIRS.

     Save and except for the one-year guaranty against defective materials and
workmanship provided in Section 2.8 hereof and the completion of the Punchlist
Items provided in Section 2.6 hereof, Tenant, at its sole cost and expense,
throughout the Term of this Lease, shall take good care of the Demised Premises;
and shall keep the same in good order, condition and repair, and irrespective of
such guaranty shall make and perform all routine maintenance thereof and (other
than as set forth in Article XIII) all necessary repairs thereto, interior and
exterior, ordinary and extraordinary, foreseen and unforeseen, of every nature,
kind and description; provided, however, that Tenant 

                                       28
<PAGE>
 
shall have no such obligation with respect to the structural elements and the
foundations of the Demised Premises. The structural elements and foundations of
the Demised Premises are collectively referred to as the "Landlord Items". When
used in this Article VIII, "repairs" shall include all necessary replacements,
renewals, alterations, additions and betterments. All repairs made by Tenant
shall be at least equal in quality and cost to the Improvements and shall be
made by Tenant in accordance with all laws, ordinances and regulations whether
heretofore or hereafter enacted. The necessity for or adequacy of maintenance
and repairs shall be measured by the standards which are appropriate for
improvements of similar construction, age and class, provided that Tenant shall
in any event make all repairs necessary to avoid any structural damage or other
damage or injury to the Improvements.

     SECTION 8.2 MAINTENANCE.

     Tenant, at its sole cost and expense, shall take good care of and shall
repair and maintain all driveways, pathways, roadways, sidewalks, curbs, parking
areas, loading areas, landscaped areas, entrances and passageways on the Demised
Premises (except for the Landlord Items) in good order and repair. Tenant shall,
when, and to the extent consistent with the conditions in the area, remove
accumulated snow, ice and debris from any and all driveways, pathways, roadways,
sidewalk, curbs, parking areas, loading areas, entrances and passageways on the
Demised Premises. Tenant shall keep all portions of the Demised Premises in a
clean and orderly condition free of snow, ice, dirt, rubbish, debris and
unlawful obstructions debris. Tenant shall keep the Demised Premises fit for
human occupancy and use.

     Tenant shall, at its own cost and expense, enter into a regularly scheduled
preventive maintenance/service contract with a maintenance contractor for
servicing all hot water, heating and air conditioning systems and equipment and
escalators and/or elevators and related equipment within or serving the Demised
Premises. The maintenance contractor and the contract must be approved by
Landlord, which approval will not be unreasonably withheld. The service contract
must include all services recommended by the equipment manufacturer within the
operation/maintenance manual and must become effective (and a copy thereof
delivered to Landlord) within thirty (30) days of the date Tenant takes
possession of the Demised Premises. The foregoing maintenance may be performed,
in whole or part, by employees of Tenant provided that the level and scope of
such maintenance is as required hereby.

     Tenant acknowledges that the floors of the Building are to be constructed
to withstand a uniformly distributed live load capacity per square foot as
required by the applicable building codes, and Tenant represents and warrants
that it will not at any time subject the floors of the Building or any part
thereof to any load exceeding such capacity. Tenant agrees that it shall use all
reasonable and prudent storage techniques including but not limited to, even
distribution of weight loads. Without limiting 

                                       29
<PAGE>
 
Tenant's obligations for repair and maintenance set forth in this Article,
Tenant shall, (following the expiration of Landlord's construction warranty as
set forth in Section 2.8), at all times repair and maintain the entire roof,
roof membrane and structure and shall keep the same in a watertight condition.
Tenant's obligations under the foregoing sentence are subject to any specific
provisions of the roof warranty referenced in Section 2.8. Other than as set
forth in Article XXI, Tenant will not allow any person not authorized by
Landlord to go upon the roof of the Building or any materials or equipment
(including but not limited to any satellite or other communications equipment)
to be placed upon the roof of the Building without prior written notice to
Landlord, except as specified in Article XXI herein. At any time that any person
goes upon such roof or any materials or equipment are placed upon such roof
(except in connection with Tenant's maintenance of Landlord permitted equipment
located on the roof), Tenant shall allow Landlord or its agent the right to
inspect and approve the expected life or integrity of the roof operation or
procedure and shall not take any action affecting the roof or the roof warranty
without Landlord's written approval.

     SECTION 8.3 TENANT'S WAIVER OF CLAIMS AGAINST LANDLORD.

     Except for Landlord's obligations set forth in this Lease, Landlord shall
not be required to furnish any services or facilities or to make any repairs or
alterations in, about or to the Demised Premises or any Improvements. Subject to
the provisions of this Lease, Tenant hereby assumes the full and sole
responsibility for the condition, operation, repair, replacement, maintenance
and management of the Demised Premises and all improvements hereafter erected
thereon, and Tenant hereby waives any rights created by any law now or hereafter
in force to make repairs to the Demised Premises or improvements hereafter
erected thereon at Landlord's expense. Subject to the provisions of this Lease,
Tenant agrees that Landlord is not liable for, and Tenant waives, all claims
against Landlord for any damage to Tenant's property or business resulting
directly or indirectly from (a) any existing or future condition, defect, matter
or thing in the Demised Premises (other than Landlord Items), or any part of the
Demised Premises (other than Landlord Items), (b) any equipment or appurtenances
becoming out of repair, (c) any occurrence, act or omission of any of the
Landlord or any other person. This Section applies especially, but not
exclusively, to damage caused by the flooding of basements or other subsurface
areas and by refrigerators, sprinkling devices, air conditioning apparatus,
water, snow, frost, steam, excessive heat or cold, falling plaster, broken
glass, sewage, gas, odors, noise or the bursting or leaking of pipes or plumbing
fixtures and applies regardless whether any such damage results from an act of
God, the act or omission of other tenants or occupants of the Demised Premises
or any other persons.

     SECTION 8.4 PROHIBITION AGAINST WASTE.

                                       30
<PAGE>
 
     Tenant shall not do or suffer any waste or damage, disfigurement or injury
to the Demised Premises, or any Improvements hereafter erected thereon, or to
the fixtures or equipment therein.

     SECTION 8.5 LANDLORD'S RIGHT TO EFFECT REPAIRS.

     In the event of an Event of Default by Tenant under this Article VIII, then
Landlord may, if it so elects and following such notice as is reasonable under
the circumstances, in addition to any other remedies provided herein, effect
such repairs and maintenance. Any sums expended by Landlord in effecting such
repairs and maintenance shall be due and payable, on demand, together with
interest thereon at the Maximum Rate of Interest from the date of each such
expenditure by Landlord to the date of repayment by Tenant.

     SECTION 8.6 MISUSE OR NEGLECT.

     Without limiting any of Tenant's obligations hereinbefore set forth, Tenant
shall be responsible for all repairs to the Demised Premises which are made
necessary by any misuse or neglect by: (i) Tenant or any of its officers,
agents, employees, contractors (other than Landlord), licensees or subtenants;
or (ii) any visitors, patrons, guests or invitees of Tenant or its subtenant
while in or upon the Demised Premises.

     SECTION 8.7 LANDLORD REPAIRS.

     Landlord will repair and maintain the Landlord Items in good order,
condition and repair. Landlord will, in accordance with its customary accounting
procedures as generally applied by Landlord to its business operations,
calculate the expenses incurred by Landlord in so maintaining and repairing the
Landlord Items after the expiration of the Landlord guaranty set forth in
Section 2.8. Those expenses will not include the cost of any capital improvement
to the Building (which capital costs will be paid by Landlord without
reimbursement from Tenant) other than replacements required for normal
maintenance and repair. The foregoing expenses will be invoiced to, and paid by,
Tenant as incurred by Landlord and will constitute items of Additional Rent.
Tenant agrees to give Landlord notice of any Landlord Item that requires repair
or maintenance. Tenant agrees to provide Landlord with access to the Demised
Premises in order to permit Landlord to perform repair and maintenance as
required hereby.

                                   ARTICLE IX
                       COMPLIANCE WITH LAWS AND ORDINANCES

     SECTION 9.1 COMPLIANCE WITH LAWS AND ORDINANCES.

                                       31
<PAGE>
 
     Tenant shall throughout the Term of this Lease, at Tenant's sole cost and
expense, promptly comply or cause compliance with or remove or cure any
violation of any and all present and future laws, ordinances, orders, rules,
regulations and requirements of all federal, state, municipal and other
governmental bodies having jurisdiction over the Demised Premises, including,
without limitation, those pertaining to indoor air quality, and the appropriate
departments, commissions, boards and officers thereof, and the orders, rules and
regulations of the Board of Fire Underwriters where the Demised Premises are
situated, or any other body now or hereafter constituted exercising lawful or
valid authority over the Demised Premises, or any portion thereof, or the
sidewalks, curbs, roadways, alleys, entrances or railroad track facilities
adjacent or appurtenant thereto (if any), or exercising authority with respect
to the use or manner of use of the Demised Premises, or such adjacent or
appurtenant facilities, and whether the compliance, curing or removal of any
such violation and the costs and expenses necessitated thereby shall have been
foreseen or unforeseen, ordinary or extraordinary, and whether or not the same
shall be presently within the contemplation of Landlord or Tenant or shall
involve any change of governmental policy, or require structural or
extraordinary repairs, alterations or additions by Tenant and irrespective of
the costs thereof.

     SECTION 9.2 COMPLIANCE WITH PERMITTED ENCUMBRANCES.

     Tenant, at its sole cost and expense, shall comply with all Permitted
Encumbrances, as they exist as of the date hereof or as they may be hereafter be
supplemented or created so long as any such supplement or new Permitted
Encumbrance is approved in writing by Tenant. Landlord shall have the right,
following thirty (30) days' notice to Tenant (except in the case of emergency),
to cure any default or (subject to Tenant's right to contest the same as set
forth in Section 9.4) claimed default by Tenant under the Permitted Encumbrances
(including any such supplements). Any sums expended by Landlord in such cure,
together with interest at the Maximum Rate of Interest from the date of each
such expenditure by Landlord to the date of repayment by Tenant, will be payable
to Landlord as Additional Rent hereunder, said payments to be made within thirty
(30) days of demand by Landlord. Tenant shall also comply with, observe and
perform all provisions and requirements of all policies of insurance at any time
in force with respect to the Demised Premises and either required to be obtained
by Tenant and maintained under the terms of Article VI hereof or of which Tenant
has been given notice and shall comply with all development permits issued by
governmental authorities issued in connection with development of the Demised
Premises.

     SECTION 9.3 TENANT'S OBLIGATIONS.

     Notwithstanding that it may be usual and customary for Landlord to assume
responsibility and performance of any or all of the obligations set forth in
this Article IX, and notwithstanding any order, rule or regulation directed to
Landlord to perform 

                                       32
<PAGE>
 
(but subject to Landlord's obligations under Article II), Tenant hereby assumes
such obligations because, by nature of this Lease, the rents and income derived
from this Lease by Landlord are net rentals not to be diminished by any expense
incident to the ownership, occupancy, use, leasing or possession of the Demised
Premises or any portion thereof.

     SECTION 9.4 TENANT'S RIGHT TO CONTEST LAWS AND ORDINANCES.

     After prior written notice to Landlord, Tenant, at its sole cost and
expense and without cost or expense to Landlord, shall have the right to contest
the validity or application of any law or ordinance referred to in this Article
IX in the name of Tenant or Landlord, or both, by appropriate legal proceedings
diligently conducted but only if compliance with the terms of any such law or
ordinance pending the prosecution of any such proceeding may legally be delayed
without the incurrence of any lien, charge or liability of any kind against the
Demised Premises, or any portion thereof, and without subjecting Landlord or
Tenant to any liability, civil or criminal, for failure so to comply therewith
until the final determination of such proceeding; provided, however, if any
lien, charge or civil liability would be incurred by reason of any such delay
Tenant may nevertheless, on the prior written consent of Landlord, contest as
aforesaid and delay as aforesaid. Landlord will not unreasonably withhold such
consent provided that such delay would not subject Tenant or Landlord to
criminal liability and Tenant (a) furnishes Landlord security, reasonably
satisfactory to Landlord, against any loss or injury by reason of any such
contest or delay, (b) prosecutes the contest with due diligence and in good
faith, and (c) agrees to indemnify, defend and hold harmless Landlord and the
Demised Premises from any charge, liability or expense whatsoever related to
such contest. The security furnished to Landlord by Tenant shall be in the form
of a cash deposit or a certificate of deposit issued by a national bank or
federal savings and loan association, payable to Landlord. Said deposit shall be
held, administered and distributed in accordance with the provisions of Section
5.2 hereof relating to the contest of the amount or validity of any Imposition.

     If necessary or proper to permit Tenant so to contest the validity or
application of any such law or ordinance, Landlord shall, at Tenant's sole cost
and expense, including reasonable attorneys' fees incurred by Landlord, execute
and deliver any appropriate papers or other documents; provided, however,
Landlord shall not be required to execute any document or consent to any
proceeding which would result in the imposition of any cost, charge, expense or
penalty on Landlord or the Demised Premises.

     SECTION 9.5 COMPLIANCE WITH HAZARDOUS MATERIALS LAWS.

     Tenant shall, at all times and in all respects with respect to its
activities on the Demised Premises, and with respect to any other activities
which have an affect upon the Demised Premises, comply with all federal, state
and local laws, ordinances and 

                                       33
<PAGE>
 
regulations ("Hazardous Materials Laws") relating to the industrial hygiene,
environmental protection or the use, analysis, generation, manufacture, storage,
presence, disposal or transportation of any oil, petroleum products, flammable
explosives, asbestos, urea formaldehyde, polychlorinated biphenyls, radioactive
materials or waste, or other hazardous, toxic, contaminated or polluting
materials, substances or wastes, including without limitation any "hazardous
substances", "hazardous wastes", "hazardous materials" or "toxic substances"
under any such laws, ordinances or regulations (collectively, "Hazardous
Materials").

     Tenant shall at its own expense procure, maintain in effect and comply with
all conditions of any and all permits, licenses and other governmental and
regulatory approvals required for Tenant's use of the Demised Premises,
including, without limitation, discharge of (appropriately treated) materials or
waste into or through any sanitary sewer system serving the Demised Premises.
Notwithstanding the preceding sentence, the Landlord shall, at its expense,
procure any such permits required for the construction of the Improvements.
Except as discharged into the sanitary sewer in strict accordance and conformity
with all applicable Hazardous Materials Laws, Tenant shall cause any and all
Hazardous Materials to be removed from the Demised Premises and transported
solely by duly licensed haulers to duly licensed facilities for final disposal
of such Hazardous Materials and wastes. Tenant shall in all respects, handle,
treat, deal with and manage any and all Hazardous Materials in, on, under or
about the Demised Premises in complete conformity with all applicable Hazardous
Materials Laws and prudent industry practices regarding the management of such
Hazardous Materials. All reporting obligations to the extent imposed upon Tenant
by Hazardous Materials Laws are solely the responsibility of Tenant. Upon
expiration or earlier termination of this Lease, Tenant shall cause all
Hazardous Materials (to the extent such Hazardous Materials are generated,
stored, released or disposed of on the Demised Premises during the Term of this
Lease) to be removed from the Demised Premises (unless such removal is not
permitted by Hazardous Materials Laws) and transported for use, storage or
disposal in accordance and in compliance with all applicable Hazardous Materials
Law. Tenant shall not take any remedial action in response to the presence of
any Hazardous Materials in, on, about or under the Demised Premises or in any
Improvements situated on the Land, nor enter into any settlement agreement,
consent, decree or other compromise in respect to any claims relating to any way
connected with the Demised Premises or the Landlord's Improvements on the Land
without first notifying Landlord of Tenant's intention to do so and affording
Landlord thirty (30) days to appear, intervene or otherwise appropriately assert
and protect Landlord's interest with respect thereto. In addition, at Landlord's
request, at the expiration of the Term of this Lease, Tenant shall remove all
tanks or fixtures which were placed on the Demised Premises during the Term of
this Lease and which contain, have contained or are contaminated with, Hazardous
Materials.

                                       34
<PAGE>
 
     Tenant shall immediately notify Landlord in writing of (a) any enforcement,
clean-up, removal or other governmental or regulatory action instituted,
completed or threatened pursuant to any Hazardous Materials Laws; (b) any claim
made or threatened by any person against Landlord, or the Demised Premises,
relating to damage, contribution, cost recovery, compensation, loss or injury
resulting from or claimed to result from any Hazardous Materials; and (c) any
reports made to any environmental agency arising out of or in connection with
any Hazardous Materials in, on or about the Demised Premises or with respect to
any Hazardous Materials removed from the Demised Premises, including, any
complaints, notices, warnings, reports or asserted violations in connection
therewith. Tenant shall also provide to Landlord, as promptly as possible, and
in any event within five (5) business days after Tenant first receives or sends
the same, copies of all claims, reports, complaints, notices, warnings or
asserted violations relating in any way to the Demised Premises or Tenant's use
thereof. Upon written request of Landlord (to enable Landlord to defend itself
from any claim or charge related to any Hazardous Materials Law), Tenant shall
promptly deliver to Landlord lists of Hazardous Waste used by Tenant on the
Demised Premises reflecting the legal and proper disposal of all such Hazardous
Materials removed or to be removed from the Demised Premises. All such lists
shall list the Tenant or its agent as a responsible party and in no way shall
attribute responsibility for any such Hazardous Materials to Landlord.

     SECTION 9.6 HAZARDOUS MATERIAL REPRESENTATION BY LANDLORD.

     To Landlord's knowledge as of the date hereof and as of the Commencement
Date, Landlord is not aware of any Hazardous Materials which exist or are
located on or in the Demised Premises, except as may be disclosed in that
certain environmental site assessment prepared by Braun-Intertec, dated
September 22, 1998. Further, Landlord represents to Tenant that; (i) to the best
of its knowledge, Landlord has not caused the generation, storage or release of
Hazardous Materials upon the Demised Premises, except in accordance with
Hazardous Materials Laws, (ii) any Hazardous Materials located on the Demised
Premises during construction of the Improvements will, by the Commencement Date,
be removed therefrom in compliance with Hazardous Materials Laws; and (iii) the
Improvements will contain no asbestos or asbestos-containing materials.
Notwithstanding anything herein to the contrary, Landlord's sole responsibility
by reason of a violation of the provisions of this Section 9.6 shall be as
follows. Landlord shall bear the entire cost related to responding to any
directive, order, judgment or decree of any governmental, judicial or regulatory
body or agency ("Agency Directive") the purpose of which is to cause the Demised
Premises to be brought into compliance with Hazardous Materials Laws; provided
that such Agency Directive relates to the circumstances giving rise to a
violation by Landlord of the provisions of this Section 9.6. In the absence of
an Agency Directive, Landlord's sole responsibility with respect to a violation
of this Section 9.6 shall be to take such corrective action as is reasonably
required in Landlord's judgment to address and 

                                       35
<PAGE>
 
correct any health or safety issues which may be related to the circumstances
giving rise to the violation of this Section 9.6.

     SECTION 9.7 COST OF COMPLIANCE WITH HAZARDOUS MATERIALS LAWS.

     Provisions of Sections 9.5 and 9.6 notwithstanding, Tenant shall be
responsible only for that part of the cost of compliance with Hazardous
Materials Laws which relates to a breach by Tenant of the representations,
warranties and covenants contained in this Lease to be kept and performed by
Tenant, including but not limited to the covenants contained in Section 9.5.
Landlord shall be responsible only for that part of the cost of compliance with
Hazardous Materials Laws which relate to a breach by Landlord of the covenants
contained in Section 9.6 of this Lease.

     SECTION 9.8 DISCOVERY OF HAZARDOUS MATERIALS.

     In the event (a) Hazardous Materials are discovered upon the Demised
Premises, (b) Landlord has been given written notice of the discovery of such
Hazardous Materials, and (c) pursuant to the provisions of Section 9.7, neither
Landlord nor Tenant is obligated to pay the cost of compliance with Hazardous
Materials Laws, then and in that event Landlord may voluntarily but shall not be
obligated to agree with Tenant to take all action necessary to bring the Demised
Premises into compliance with Hazardous Materials Laws at Landlord's sole cost.
In the event Landlord fails to notify Tenant in writing within thirty (30) days
of the notice to Landlord of the discovery of such Hazardous Materials that
Landlord intends to voluntarily take such action as is necessary to bring the
Demised Premises into compliance with Hazardous Materials Laws, then Tenant as
its sole and exclusive right and remedy against Landlord therefor may bring the
Demised Premises into compliance with Hazardous Materials Laws at Tenant's sole
cost.

     SECTION 9.9 INDEMNIFICATION.

     Tenant shall indemnify, defend (with counsel reasonably acceptable to
Landlord), protect and hold harmless Landlord and each of Landlord's officers,
directors, partners, employees, agents, attorneys, successors and assigns from
and against any and all claims, liabilities, damages, costs, penalties,
forfeitures, losses or expenses (including attorneys' fees) for death or injury
to any person or damage to any property whatsoever (including water tables and
atmosphere) arising or resulting in whole or in part, directly or indirectly,
from the presence or discharge of Hazardous Materials, in, on, under, upon or
from the Demised Premises or the Improvements located thereon or from the
transportation or disposal of Hazardous Materials to or from the Demised
Premises (the standard herein being one of strict liability) unless Tenant
establishes: (i) that the same were caused by Landlord or that Landlord is
otherwise responsible therefore under the provisions of Section 9.6; or (ii)
that the discharge or release did not occur during the Term. Tenant's
obligations hereunder 

                                       36
<PAGE>
 
shall include, without limitation, and whether foreseeable or unforeseeable, all
costs of any required or necessary repairs, clean-up or detoxification or
decontamination of the Demised Premises or the Improvements, and the presence
and implementation of any closure, remedial action or other required plans in
connection therewith, and shall survive the expiration of or early termination
of the Term of this Lease. For purposes of the indemnity provided herein, any
acts or omissions of Tenant, or its employees, agents, customers, sub-lessees,
assignees, contractors or sub-contractors of Tenant (whether or not they are
negligent, intentional, willful or unlawful) shall be strictly attributable to
Tenant. For the purpose of the foregoing sentence, the term "contractors" does
not include Landlord.

     SECTION 9.10 ENVIRONMENTAL AUDITS.

     Upon reasonable request by Landlord during the Term of this Lease, prior to
the exercise of any renewal right and/or prior to vacating the Demised Premises,
Tenant shall undertake and submit to Landlord an environmental audit from an
environmental company reasonably acceptable to Landlord, which audit shall
evidence Tenant's compliance with this Article IX.

     SECTION 9.11 ACTS OR OMISSIONS REGARDING HAZARDOUS MATERIALS.

     For purposes of the covenants and agreements contained in Sections 9.5
through 9.10, inclusive, any acts or omissions of Tenant, its employees, agents,
customers, sublessees, assignees, contractors or sub-contractors shall be
strictly attributable to Tenant. For the purpose of the foregoing sentence, the
term "contractors" does not include Landlord. No third party may rely upon, or
claim third party beneficiary status with respect to the foregoing.

     SECTION 9.12 ADA REQUIREMENTS.

     In both the design and construction of Landlord Improvements and the
construction of the Tenant Improvements, Landlord shall be responsible for the
full compliance thereof with the accessibility requirements of Title III of the
applicable provisions of the Americans with Disabilities Act of 1990 (the "ADA")
as of the Commencement Date. Nevertheless, Landlord shall not have
responsibility for code compliance or other ADA-related matters relating to the
following: (i) any work of Tenant or its separate contractors, or by
installations which are not part of Landlord's Improvements, (ii) any work
included within the Landlord's Improvements, to the extent that such work is
other than normal and customary construction for a typical user similar to
Tenant, (iii) any matters arising by reason of a change in the ADA or other laws
or building codes applicable to the Demised Premises following the Commencement
Date, (iv) any alterations or improvements, whether or not included in the
Landlord's Improvements, which are required in order to comply with ADA or
similar laws or building codes to the extent caused by or contributed to by
reason of the 

                                       37
<PAGE>
 
fact that Tenant may employ more than an average number of persons with a mental
or physical disability; or (v) the design of the Tenant Improvements. All
compliance with ADA as it relates to the Tenant Improvements shall be Tenant's
responsibility.

     SECTION 9.13 SURVIVAL.

     The respective rights and obligations of Landlord and Tenant under this
Article IX shall survive the expiration or earlier termination of this Lease.


                                    ARTICLE X
                        MECHANIC'S LIENS AND OTHER LIENS

     SECTION 10.1 FREEDOM FROM LIENS.

     Tenant shall not suffer or permit any mechanic's lien or other lien to be
filed against the Demised Premises, or any portion thereof, by reason of work,
labor, skill, services, equipment or materials supplied or claimed to have been
supplied to the Demised Premises at the request of Tenant, or anyone holding the
Demised Premises, or any portion thereof, through or under Tenant. If any such
mechanic's lien or other lien shall at any time be filed against the Demised
Premises , or any portion thereof, Tenant shall cause the same to be discharged
of record within thirty (30) days after the date of filing the same. If Tenant
shall fail to discharge such mechanic's lien or liens or other lien within such
period, then, in addition to any other right or remedy of Landlord, after five
(5) days prior written notice to Tenant, Landlord may, but shall not be
obligated to, discharge the same by paying to the claimant the amount claimed to
be due or by procuring the discharge of such lien as to the Demised Premises by
deposit in the court having jurisdiction of such lien, the foreclosure thereof
or other proceedings with respect thereto, of a cash sum sufficient to secure
the discharge of the same, or by the deposit of a bond or other security with
such court sufficient in form, content and amount to procure the discharge of
such lien, or in such other manner as is now or may in the future be provided by
present or future law for the discharge of such lien as a lien against the
Demised Premises. Any amount paid by Landlord, or the value of any deposit so
made by Landlord, together with all costs, fees and expenses in connection
therewith (including reasonable attorneys' fees of Landlord), together with
interest thereon at the Maximum Rate of Interest set forth in Section 3.4
hereof, shall be repaid by Tenant to Landlord on demand by Landlord and if
unpaid may be treated as Additional Rent. Tenant shall indemnify, defend and
hold harmless Landlord and the Demised Premises, and any portion thereof, from
all losses, costs, damages, expenses, liabilities, suits, penalties, claims,
demands and obligations, including, without limitation, reasonable attorneys'
fees resulting from the assertion, filing, foreclosure or other legal
proceedings with respect to any such mechanic's lien or other lien.

                                       38
<PAGE>
 
     All materialmen, contractors (other than Landlord), artisans, mechanics,
laborers and any other person now or hereafter furnishing any labor, services,
materials, supplies or equipment to Tenant with respect to the Demised Premises,
or any portion thereof, are hereby charged with notice that they must look
exclusively to Tenant to obtain payment for the same. Notice is hereby given
that Landlord shall not be liable for any labor, services, materials, supplies,
skill, machinery, fixtures or equipment furnished or to be furnished to Tenant
upon credit, and that no mechanic's lien or other lien for any such labor,
services, materials, supplies, machinery, fixtures or equipment shall attach to
or affect the state or interest of Landlord in and to the Demised Premises, or
any portion thereof.

     SECTION 10.2 LANDLORD'S INDEMNIFICATION.

     The provisions of Section 10.1 above shall not apply to any mechanic's lien
or other lien for labor, services, materials, supplies, machinery, fixtures or
equipment furnished to the Demised Premises in the performance of Landlord's
obligations to construct the Improvements required by the provisions of Article
II hereof, and (notwithstanding the disclaimer in Section 8.3), Landlord does
hereby agree to indemnify, defend and hold harmless Tenant and the Demised
Premises, and any portion thereof, from all losses, costs, damages, expenses,
liabilities and obligations, including, without limitation, reasonable
attorneys' fees resulting from the assertion, filing, foreclosure or other legal
proceedings with respect to any such mechanic's lien or other lien.

     SECTION 10.3 REMOVAL OF LIENS.

     Except as otherwise provided for in this Article X, Tenant shall not
create, permit or suffer, and shall promptly discharge and satisfy of record,
any other lien, encumbrance, charge, security interest or other right or
interest which shall be or become a lien, encumbrance, charge or security
interest upon the Demised Premises, or any portion thereof, or the income
therefrom, or on the interest of Landlord or Tenant in the Demised Premises, or
any portion thereof, save and except for those liens, encumbrances, charges,
security interests or other rights or interests consented to, in writing, by
Landlord, or those mortgages, assignments of rents, assignments of leases and
other mortgage documentation placed thereon by Landlord in financing or
refinancing the Demised Premises.


                                   ARTICLE XI
                                INTENT OF PARTIES

     SECTION 11.1 NET LEASE.

                                       39
<PAGE>
 
     Landlord and Tenant do each state and represent that it is the intention of
each of them that this Lease be interpreted and construed as an absolute net
lease and all Basic Rent and Additional Rent shall be paid by Tenant to Landlord
without abatement, deduction, diminution, deferment, suspension, reduction or
setoff, and the obligations of Tenant shall not be affected by reason of damage
to or destruction of the Demised Premises from whatever cause (except as
provided in Article XIII), nor shall the obligations of Tenant be affected by
reason of any condemnation, eminent domain or like proceedings (except as
provided in Article XIV hereof); nor shall the obligations of Tenant be affected
by reason of any other cause whether similar or dissimilar to the foregoing or
by any laws or customs to the contrary. It is the further express intent of
Landlord and Tenant that: (a) the obligations of Landlord and Tenant hereunder
shall be separate and independent covenants and agreements and that the Basic
Rent and Additional Rent, and all other charges and sums payable by Tenant
hereunder, shall commence at the times provided herein and shall continue to be
payable in all events unless the obligations to pay the same shall be terminated
pursuant to an express provision in this Lease; (b) except as otherwise set
forth in this Lease, all costs or expenses of whatsoever character or kind,
general or special, ordinary or extraordinary, foreseen or unforeseen, and of
every kind and nature whatsoever that may be necessary or required in and about
the Demised Premises, or any portion thereof, and Tenant's possession or
authorized use thereof during the Term of this Lease, shall be paid by Tenant
and all provisions of this Lease are to be interpreted and construed in light of
the intention expressed in this Section 11.1; (c) the Basic Rent specified in
Article III shall be absolutely net to Landlord so that Landlord shall be paid
the entire Basic Rent specified in Article III in each year during the Term of
this Lease (unless extended or renewed at a different Basic Rent); (d) except as
otherwise set forth in this Lease, all Impositions, insurance premiums, utility
expense, repair and maintenance expense, and all other costs, fees, interest,
charges, expenses, reimbursements and obligations of every kind and nature
whatsoever relating to the Demised Premises, or any portion thereof, which may
arise or become due during the Term of this Lease, or any extension or renewal
thereof, shall be paid or discharged by Tenant as Additional Rent; and (e)
Tenant hereby agrees to indemnify, defend and save Landlord harmless from and
against such costs, fees, charges, expenses, reimbursements and obligations, any
interest thereon. Nothing in the foregoing Section 11.1 shall diminish Tenant's
right to assert a claim against Landlord under Section 2.8 hereof.

     SECTION 11.2 ENTRY BY LANDLORD.

     If Tenant shall at any time fail to pay any Imposition in accordance with
the provisions of Article V, or to take out, pay for, maintain and deliver any
of the insurance policies or certificates of insurance provided for in Article
VI, or shall fail to make any other payment or perform any other act on its part
to be made or performed, then Landlord, after prior written notice to Tenant as
provided in Section 12.1 (or with such notice as is reasonable in case of
emergency), and without waiving or releasing 

                                       40
<PAGE>
 
Tenant from any obligation of Tenant contained in this Lease, may, but shall be
under no obligation to do so, (a) pay any Imposition payable by Tenant pursuant
to the provisions of Article V; (b) take out, pay for and maintain any of the
insurance policies provided for in this Lease; or (c) make any other payment or
perform any other act on Tenant's part to be paid or performed as in this Lease
provided, and Landlord may, following such notice as is reasonable in the
circumstances, enter upon the Demised Premises for any such purpose and take all
such action therein or thereon as may be necessary therefor. Nothing herein
contained shall be deemed as a waiver or release of Tenant from any obligation
of Tenant contained in this Lease. In exercising such right of entry, Landlord
will use reasonable commercial efforts to assure that its personnel do not
observe or disclose confidential information of Tenant located at the Demised
Premises so long as Tenant has used reasonable commercial efforts to protect
such information from observation.

     SECTION 11.3 INTEREST ON UNPAID AMOUNTS.

     If Tenant shall fail to perform any act required of it, Landlord may
perform the same, but shall not be required to do so, in such manner and to such
extent as Landlord may deem necessary or desirable, and in exercising any such
right to employ counsel and to pay necessary and incidental costs and expenses,
including reasonable attorneys' fees. All sums so paid by Landlord and all
necessary and incidental costs and expenses, including reasonable attorneys'
fees, in connection with the performance of any such act by Landlord, together
with interest thereon at the Maximum Rate of Interest provided in Section 3.4
hereof from the date of making such expenditure by Landlord, shall be deemed
Additional Rent hereunder and, except as is otherwise expressly provided herein,
shall be payable to Landlord on demand or, at the option of Landlord, may be
added to any monthly rental then due or thereafter becoming due under this
Lease, and Tenant covenants to pay any such sum or sums, with interest as
aforesaid, and Landlord shall have, in addition to any other right or remedy of
Landlord, the same rights and remedies in the event of nonpayment thereof by
Tenant as in the case of default by Tenant in the payment of monthly Basic Rent.
Landlord shall not be limited in the proof of any damages which Landlord may
claim against Tenant arising out of or by reason of Tenant's failure to provide
and keep in force insurance as aforesaid, to the amount of the insurance premium
or premiums not paid or not incurred by Tenant, and which would have been
payable upon such insurance, but Landlord shall also be entitled to recover as
damages for such breach the uninsured amount of any loss (to the extent of any
deficiency between the dollar limits of insurance required by the provisions of
this Lease and the dollar limits of the insurance actually carried by Tenant),
damages, costs and expenses of suit, including reasonable attorneys' fees,
suffered or incurred by reason of damage to or destruction of the Demised
Premises, or any portion thereof or other damage or loss which Tenant is
required to insure against hereunder, occurring during any period when Tenant
shall have failed or neglected to provide insurance as aforesaid.

                                       41
<PAGE>
 
                                   ARTICLE XII
                               DEFAULTS OF TENANT

     SECTION 12.1 EVENT OF DEFAULT.

     Any one or more of the following events (in this Article sometimes called
"Events of Default") shall be deemed an Event of Default by Tenant under this
Lease:

     (i) If default shall be made by Tenant, by operation of law or otherwise,
     under the provisions of Article XV hereof relating to assignment, sublease,
     mortgage or other transfer of Tenant's interest in this Lease or in the
     Demised Premises or in the income arising therefrom;

     (ii) If default shall be made in the due and punctual payment of any Basic
     Rent or Additional Rent payable under this Lease or in the payment of any
     obligation to be paid by Tenant, when and as the same shall become due and
     payable, and said default is not cured within ten (10) days of written
     notice from Landlord. Notwithstanding the ten (10) day cure period in the
     immediately preceding sentence, Tenant acknowledges and agrees that Basic
     Rent and Additional Rent is due and payable, without delay, on the various
     days specified elsewhere in this Lease and that the Maximum Rate of
     Interest and any late payment fees specified in Section 3.4 herein shall
     apply from the date Basic Rent and Additional Rent is first due.

     (iii) If default shall be made by Tenant in keeping, observing or
     performing any of the terms contained in this Lease, other than those
     referred to in Subsections (i), (ii) and (v) of this Section 12.1, which
     does not expose Landlord to criminal liability, and such default shall
     continue for a period of thirty (30) days after written notice thereof
     given by Landlord to Tenant. In the case of such a default or contingency
     (other than one which may expose Landlord to criminal liability) which
     cannot with due diligence and in good faith be cured within thirty (30)
     days, if Tenant fails to proceed promptly and with due diligence and in
     good faith to cure the same or if Tenant fails to thereafter prosecute the
     curing of such default with due diligence and in good faith, or if such
     default is not cured within sixty (60) days after written notice thereof
     given by Landlord to Tenant, subject to matters of Excused Delay (but not
     including any delay caused or contributed to by act or neglect of Tenant or
     those acting for or under Tenant). Notwithstanding anything contained
     herein to the contrary, in the event Tenant fails to take out, pay for,
     maintain or deliver any of the insurance policies provided for in Article
     VI herein, Landlord need not give Tenant written notice or any period to
     cure such default prior to taking any actions authorized pursuant to
     Section 11.2 of this Lease; and

                                       42
<PAGE>
 
     (iv) If default shall be made by Tenant in keeping, observing or performing
     any of the terms contained in this Lease, other than those referred to in
     Subsections (i), (ii), (iii) and (v) of this Section 12.1, and which
     reasonably exposes Landlord to criminal liability, and such default shall
     continue for five (5) days after written notice thereof given by Landlord
     to Tenant, and Tenant fails within said five (5) days to cure the same, it
     being intended that in connection with a default which reasonably exposes
     Landlord to criminal liability that Tenant shall proceed immediately to
     cure or correct such condition.

     (v) Tenant makes a general assignment or general arrangement for the
     benefit of creditors; (b) a petition for adjudication of bankruptcy or for
     reorganization or rearrangement is filed by Tenant or is filed against
     Tenant and with respect to a petition filed against Tenant if such petition
     is not dismissed within seventy (75) days; (c) a trustee or receiver is
     appointed to take possession of substantially all of Tenant's assets
     located at the Demised Premises or of Tenant's interest in this Lease and
     possession is not restored to Tenant within forty-five (45) days; or (d)
     substantially all of Tenant's assets located at the Demised Premises or of
     Tenant's interest in this Lease is subjected to attachment, execution or
     other judicial seizure not discharged within forty-five (45) days. If a
     court of competent jurisdiction determines that any of the acts described
     in this Section 12.1(v) does not constitute an Event of Default, and the
     court appoints a trustee to take possession of the Demised Premises (or if
     Tenant remains a debtor in possession of the Demised Premises) and such
     trustee or Tenant transfers Tenant's interest hereunder, then Landlord is
     entitled to receive, as Additional Rent, any excess of the Rent (or any
     other consideration) paid in connection with the transfer over the Rent
     otherwise payable by Tenant under this Lease.

Upon the occurrence of any Event of Default, Landlord shall have the option to
pursue any one or more of the remedies set forth in this Article XII without any
notice or demand whatsoever, other than the notices specifically described above
in this Section 12.1. The notices set forth in this Section are intended to
satisfy any and all notice requirements imposed by law on Landlord and are not
in addition to any such requirement.

     SECTION 12.2 REMAIN OUT OF POSSESSION.

     Landlord shall have the option to remain out of possession of the Demised
Premises following an Event of Default and treat the Lease Term as subsisting.
Landlord's remedies to recover monetary damages are defined hereinafter.

     SECTION 12.3 REPOSSESSION FOLLOWING DEFAULT.

                                       43
<PAGE>
 
     Landlord shall have the option to enter upon and take possession of the
Demised Premises, with or without terminating this Lease, and expel or remove
Tenant and any other person who may be occupying the Demised Premises or any
part thereof, without being liable for prosecution or any claim for damages
therefor. Landlord shall have the right to change the locks on any door of the
Demised Premises without notifying Tenant of the name, address or telephone
number of an individual or company from whom a new key may be obtained, nor
shall Landlord have any obligation to provide a new key to Tenant. Landlord's
remedies to recover monetary damages are defined hereinafter.

     SECTION 12.3A RIGHT TO RE-ENTER.

     Landlord shall have the right, without notice (other than as required
herein), to repossess and re-enter the Demised Premises with or without
terminating this Lease. Landlord's remedies to recover monetary damages are
defined hereinafter.

     No repossession under Section 12.3 or re-entry of the Demised Premises by
Landlord shall be construed as an election on its part to terminate this Lease,
unless a written notice of termination be given to Tenant pursuant to Section
12.3B below. Notwithstanding any such repossession or re-entry, Landlord may at
any time thereafter elect to terminate this Lease for a previous default.

     SECTION 12.3B TERMINATION OF LEASE.

     Landlord may give written notice to Tenant stating that this Lease and the
terms hereof shall expire and terminate on the date specified in such notice,
and upon the date specified in such notice this Lease and the terms hereof, and
all rights of Tenant under this Lease, including all rights of renewal whether
exercised or not, shall expire and terminate.

     SECTION 12.4 PERFORMANCE OF TENANT OBLIGATIONS.

     Landlord shall have the right at all times to enter upon the Demised
Premises as provided for in Section 11.2 herein, without being liable for
prosecution or any claim for damages therefor, and do whatever Tenant is
obligated to do under the terms of this Lease; and Tenant agrees to reimburse
Landlord on demand for any expenses which Landlord may incur in thus effecting
compliance with Tenant's obligations under this Lease, and Tenant further agrees
that Landlord shall not be liable for any damages resulting to the Tenant from
such action (other than with respect to Landlord's intentional or grossly
negligent act).

     SECTION 12.5 SURRENDER OF DEMISED PREMISES.

                                       44
<PAGE>
 
     Upon any expiration or termination of this Lease, or repossession or
re-entry of the Demised Premises, Tenant shall quit and peaceably surrender the
Demised Premises and all portions thereof to Landlord. Landlord, upon or at any
time after any such expiration, termination, repossession or re-entry may
without further notice, enter upon and reenter the Demised Premises, and all
portions thereof, and possess and repossess itself thereof, by force, as
provided by Court Order (without being liable for prosecution or any claim for
damages therefor), summary proceeding, ejectment or otherwise, and may
dispossess Tenant and remove Tenant and all other persons and property from the
Demised Premises, and all portions thereof, and may have, hold and enjoy the
Demised Premises and the right to receive all rental and other income of and
from the same.

     SECTION 12.6 RELETTING BY LANDLORD.

     At any time or from time to time after any such expiration, termination,
repossession or re-entry, Landlord may relet the Demised Premises, or any
portion thereof, in the name of Landlord or otherwise, for such term or terms
(which may be greater or less than the period which would otherwise have
constituted the balance of the Term of this Lease) and on such conditions (which
may include concessions or free rent) as Landlord, in its uncontrolled
discretion, may determine and may collect and receive the rents therefor.
Landlord shall in no way be responsible or liable for any failure to relet the
Demised Premises, or any part thereof, or for any failure to collect any rent
due upon any such relenting.

     SECTION 12.7 SURVIVAL OF TENANT'S OBLIGATIONS.

     No repossession or re-entry of the Demised Premises shall relieve Tenant of
its liabilities and obligations under this Lease (as if the Demised Premises had
not been so repossessed or re-entered), and such liabilities and obligations
shall survive any such repossession or re-entry. In the event of any expiration
or termination, whether or not the Demised Premises or any portion thereof shall
have been relet, Tenant shall pay to Landlord a sum equal to the Basic Rent, the
Additional Rent and any other charges required to be paid by Tenant, up to the
time of such expiration or termination, as provided for in Section 12.7A herein.

     SECTION 12.7A RENT DURING REPOSSESSION AND RE-LETTING.

     In the event of any repossession or re-letting of the Demised Premises
without expiration or termination of this Lease, Tenant shall pay the following
amounts to Landlord until the expiration or termination of this Lease:

     (i) The Basic Rent and Additional Rent payable for the unexpired portion of
     the Term, less

                                       45
<PAGE>
 
     (ii) The net proceeds of any reletting effected pursuant to the provisions
     of Section 12.6 hereof after deducting all of Landlord's expenses in
     connection with such reletting, including without limitation, all
     repossession costs, brokerage commissions, legal expenses, reasonable
     attorney's fees, alteration costs, and expenses of preparation of the
     Demised Premises, or any portion thereof, for such reletting; provided that
     such expenses are generally consistent with circumstances then prevailing
     in the greater Minneapolis/St. Paul metropolitan area market place for
     similar transactions. Any such brokerage commissions, alteration costs or
     expenses of preparation of the Demised Premises actually recovered from a
     subsequent or replacement tenant shall not be recoverable from Tenant.

     Tenant shall pay the amounts determined in accordance with the terms of
this Section 12.7A, (hereinafter called the "Deficiency"), to Landlord in
monthly installments on the days on which the Basic Rent is payable under this
Lease, and Landlord shall be entitled to recover from Tenant each monthly
installment of the Deficiency as the same shall arise.

     SECTION 12.8 EXPIRATION AND TERMINATION DAMAGES.

     In the event of any expiration or termination of this Lease, whether or not
Landlord shall have collected any monthly Deficiency as set forth in Section
12.7A, Landlord shall be entitled to recover from Tenant, and Tenant shall pay
to Landlord, on demand, as and for liquidated and agreed damages for Tenant's
default, and for the loss of the bargain and not as a penalty, an amount equal
to the difference between the then present worth of the aggregate of the Basic
Rent and Additional Rent and any other charges to be paid by Tenant hereunder
for the unexpired portion of the Term (assuming this Lease had not been so
terminated), and the then present worth of the then aggregate fair and
reasonable fair market rent of the Demised Premises for the same period. In the
computation of present worth, a discount at the rate of nine percent (9%) per
annum shall be employed. Landlord and Tenant agree that Landlord's actual
damages would be difficult or impossible to ascertain, and that the amount set
forth herein represents a reasonable and fair estimate of Landlord's actual
damages. If the Demised Premises, or any portion thereof, be relet by Landlord
for the unexpired Term, or any part thereof, before presentation of proof of
such damages to any court, commission or tribunal, the amount of rent reserved
upon such reletting shall, prima facie, be the fair and reasonable fair market
rent for the part or the whole of the Demised Premises so relet during the term
of the reletting. Nothing contained in this Section 12.8 or elsewhere in Article
12 shall limit or prejudice the right of Landlord to prove and obtain, as
damages by reason of such expiration or termination, an amount equal to the
maximum allowed by any statute or rule of law in effect at the time when, and
governing the proceedings in which, such damages are to be proved, whether or
not such amount be greater, equal to or less than the amount of the difference
referred to above.

                                       46
<PAGE>
 
     SECTION 12.9 NO WAIVER.

     No failure by Landlord or by Tenant to insist upon the performance of any
of the terms of this Lease or to exercise any right or remedy consequent upon a
breach thereof, and no acceptance by Landlord of full or partial rent from
Tenant or any third party during the continuance of any such breach, shall
constitute a waiver of any such breach or of any of the terms of this Lease.
None of the terms of this Lease to be kept, observed or performed by Landlord or
by Tenant, and no breach thereof, shall be waived, altered or modified except by
a written instrument executed by Landlord and/or by Tenant, as the case may be.
No waiver of any breach shall affect or alter this Lease, and each of the terms
of this Lease shall continue in full force and effect with respect to any other
then existing or subsequent breach of this Lease. No waiver of any default of
Tenant herein shall be implied from any omission by Landlord to take any action
on account of such default. No express waiver shall affect any default other
than the default specified in the express waiver and that only for the time and
to the extent therein stated. One or more waivers by Landlord shall not be
construed as a waiver of a subsequent breach of the same covenant, term or
condition.

     SECTION 12.10 CUMULATIVE REMEDIES.

     In the event of any breach or threatened breach by Tenant of any of the
terms contained in this Lease, Landlord shall be entitled to enjoin such breach
or threatened breach and shall have the right to invoke any other right or
remedy allowed at law, in equity, by statute or otherwise, as though entry,
reentry, summary proceedings and other remedies were not provided for in this
Lease. Each remedy or right of Landlord provided for in this Lease shall be
cumulative and shall be in addition to every other right or remedy provided for
in this Lease, or now or hereafter existing at law, in equity, by statute or
otherwise. The exercise or the beginning of the exercise by Landlord of any one
or more of such rights or remedies shall not preclude the simultaneous or later
exercise by Landlord of any or all other rights or remedies.

     Tenant shall reimburse Landlord, upon demand, for any reasonable costs or
expenses incurred by Landlord in connection with any breach or default of Tenant
under this Lease, whether or not suit is commenced or judgment entered. Such
costs shall include reasonable legal fees and costs incurred for the negotiation
of a settlement, enforcement of rights or other action taken by Landlord on
account of Tenant's default. Tenant shall also indemnify, protect, defend and
hold harmless Landlord from all costs, expenses, demands and liability
(including, without limitations, attorneys' fees and costs, including attorneys'
fees as a result of the enforcement of this indemnity) incurred by Landlord if
Landlord becomes or is made a party to any claim or action (a) instituted by
Tenant, or by any third party against Tenant, or by or against any person
holding any interest under or using the Demised Premises by license of or
agreement with Tenant; (b) for foreclosure of any lien for labor or material
furnished to or for Tenant or such other person other than with 

                                       47
<PAGE>
 
respect to the Improvements; (c) otherwise arising out of or resulting from any
act or transaction of Tenant or such other person; or (d) necessary to protect
Landlord's interest under this Lease in a bankruptcy proceeding, or other
proceeding under Title 11 of the United States Code, as amended. Tenant shall
defend Landlord against any such claim or action at Tenant's expense with
counsel reasonably acceptable to Landlord or, at Landlord's election, Tenant
shall reimburse Landlord for any legal fees or costs incurred by Landlord in any
such claim or action.

     SECTION 12.11 WAIVER BY TENANT.

     Tenant hereby expressly waives, so far as permitted by law, any and all
right of redemption or reentry or repossession or to revive the validity and
existence of this Lease in the event that Tenant shall be dispossessed by a
judgment or by order of any court having jurisdiction over the Demised Premises
or the interpretation of this Lease or in case of entry, reentry or repossession
by Landlord or in case of any expiration or termination of this Lease.


                                  ARTICLE XIII
                           DESTRUCTION AND RESTORATION

     SECTION 13.1 TENANTABLE WITHIN 180 DAYS.

     If fire or other casualty renders the whole or any material part of the
Demised Premises untenantable, (or deprives the Demised Premises of access to a
public road) and Landlord reasonably expects (in Landlord's reasonable
discretion) to make the Demised Premises tenantable within 180 days after the
date of the casualty, then Landlord shall give written notice to Tenant that
Landlord will repair and restore the Building and the Demised Premises to as
near their condition prior to the casualty as is reasonably possible within the
one hundred eighty (180) day period (subject to delays caused by Excused Delay);
provided, however, that Landlord will have no such obligation with respect to
any casualty loss occurring during the latest to occur of (i) the last twelve
(12) months of the Initial Term; or (ii) the last twelve (12) months of any
Renewal Term which has been irrevocably exercised. as it may have been extended.
Landlord will mail the notice within thirty (30) days after the date of the
casualty. In such case, this Lease remains in full force and effect, but Rent
for the period during which the Demised Premises are untenantable abates prorata
(based upon the rentable square footage of the untenantable portion of the
Demised Premises as compared with the total rentable square footage of the
Demised Premises). If Landlord is required to repair the Demised Premises,
Landlord will undertake and prosecute the repair with commercially reasonable
diligence and speed.

                                       48
<PAGE>
 
     SECTION 13.2 NOT TENANTABLE WITHIN 270 DAYS.

     If fire or other casualty renders the whole or any material part of the
Demised Premises untenantable and Landlord notifies Tenant that Landlord does
not reasonably expect (in Landlord's reasonable discretion) to make the Demised
Premises tenantable within two hundred seventy (270) days after the date of the
casualty, then either party, by notifying the other within thirty (30) days
after Tenant's receipt of the Landlord's notice, may terminate this Lease
effective on a date within thirty (30) days after the date of the notice.

     If fire or other casualty renders the whole or any material part of the
Demised Premises untenantable and Landlord notifies Tenant that Landlord
reasonably expects (in Landlord's reasonable discretion) to make the Demised
Premises tenantable in more than one hundred eighty (180) but less than two
hundred seventy (270) days after the date of the casualty, and if (in Landlord's
reasonable judgment) there will be at least five (5) years of Term remaining
upon Substantial Completion of the repair of the casualty, then Landlord will
proceed to make such repairs. If, however, (in Landlord's reasonable judgment)
there will not be at least five (5) years of Term remaining upon Substantial
Completion of the repair of the casualty, then either party, by notifying the
other within thirty (30) days after Tenant's receipt of the notice of that fact
from Landlord, may terminate this Lease effective on a date within thirty (30)
days after the date of the notice.

     SECTION 13.3 DEMISED PREMISES SUBSTANTIALLY DAMAGED.

     If the Demised Premises are damaged or destroyed by fire or other casualty
and the damage reduces the Market Rent (as defined in Article XXII) of the
Demised Premises by more than fifty percent (50%) (as Landlord reasonably
determines Market Rent before and after the casualty), regardless of whether
Landlord would otherwise be required to repair the casualty as provided for in
Section 13.1 or 13.2 herein, then Landlord may, at Landlord's option, by
notifying Tenant within thirty (30) days after the casualty, terminate this
Lease effective on a date within thirty (30) days after the date of the notice.

                                       49
<PAGE>
 
     SECTION 13.4 INSUFFICIENT PROCEEDS.

     Notwithstanding any contrary language contained in this Article 13, if fire
or other casualty renders any part of the Demised Premises untenantable and
Landlord does not receive sufficient insurance proceeds (including the amount of
any policy deductible, which deductible amounts shall in all events be promptly
paid to the Landlord by the Tenant ) to make the repair, then Landlord may, at
Landlord's option, by notifying Tenant within sixty (60) days after the
casualty, terminate this Lease effective on a date within sixty (60) days after
the date of notice.

     SECTION 13.5 LANDLORD'S REPAIR OBLIGATIONS.

     If the Landlord is obligated, by the foregoing provisions of Article XIII,
to restore the Demised Premises following a casualty loss, then Landlord will
repair and restore the Demised Premises to as near their condition prior to the
fire or other casualty as is reasonably possible with all commercially
reasonable diligence and speed (subject to delays caused by Excused Delay) and
Rent for the period during which the Demised Premises are untenantable will
abate prorata (based upon the tenantable portion of the Demised Premises
compared to the total rentable square footage of the Demised Premises). In no
event is Landlord obligated to repair or restore any Alterations, Tenant
Improvements, special equipment or improvements installed by Tenant.

     SECTION 13.6 RENT APPORTIONMENT.

     If either Landlord or Tenant terminates this Lease under this Article 13,
Landlord will apportion Rent on a per diem basis and Tenant will pay the Rent to
(a) the date of the fire or other casualty if the event renders the Demised
Premises completely untenantable or (b) if the event does not render the Demised
Premises completely untenantable, the date of such termination (provided that if
a portion of the Demised Premises is rendered untenantable, but the remaining
portion is tenantable, Tenant's obligation to pay Rent abates prorata [based
upon the rentable square footage of the untenantable portion of the Demised
Premises compared with the rentable square footage of the Demised Premises as a
whole] from the date of the casualty and Tenant will pay the unabated portion of
the Rent to the date of termination).


                                   ARTICLE XIV
                                  CONDEMNATION

     SECTION 14.1 CONDEMNATION OF ENTIRE DEMISED PREMISES.

                                       50
<PAGE>
 
     If, during the Term of this Lease, the entire Demised Premises shall be
taken as the result of the exercise of the power of eminent domain (hereinafter
referred to as the "Proceedings"), this Lease and all right, title and interest
of Tenant hereunder shall cease and come to an end on the date of vesting of
title pursuant to such Proceedings and Landlord shall be entitled to and shall
receive the total award made in such Proceedings, Tenant hereby assigning any
interest in such award, damages, consequential damages and compensation to
Landlord and Tenant hereby waiving any right Tenant has now or may have under
present or future law to receive any separate award of damages for its interest
in the Demised Premises, or any portion thereof, or its interest in this Lease.
Reference is made to Section 23.1 for provisions with respect to allocating such
award following an Expansion Amendment.

     In any taking of the Demised Premises, or any portion thereof, whether or
not this Lease is terminated as in this Article provided, Tenant shall not be
entitled to any portion of the award for the taking of the Demised Premises or
damage to the Improvements, (except for any separate award to Tenant for
relocation expenses, takings of personal property not part of the Improvements,
takings of Tenant's furniture, fixtures or equipment, and except as otherwise
provided for in Section 14.3 with respect to the restoration of the
Improvements), or for the estate or interest of Tenant therein, all such award,
damages, consequential damages and compensation being hereby assigned to
Landlord. Tenant hereby waives any right it now has or may have under present or
future law to receive any separate award of damages for its interest in the
Demised Premises, or any portion thereof, or its interest in this Lease, except
that Tenant shall have, nevertheless, the limited right to prove in the
Proceedings and to receive any award which may be made for damages to or
condemnation of Tenant's movable trade fixtures and equipment, and for Tenant's
relocation costs in connection therewith.

     SECTION 14.2 PARTIAL CONDEMNATION/TERMINATION OF LEASE.

     If, during the Initial Term of this Lease, or any extension or renewal
thereof, less than the entire Demised Premises, but more than twenty-five
percent (25%) of the floor area of the Building, or more than thirty percent
(30%) of the land area of the Demised Premises, shall be taken in any such
Proceedings, this Lease shall, upon vesting of title in the Proceedings,
terminate as to the portion of the Demised Premises so taken, and Tenant may, at
its option, terminate this Lease as to the remainder of the Demised Premises.
Tenant shall not have the right to terminate this Lease pursuant to the
preceding sentence unless (a) the business of Tenant conducted in the portion of
the Demised Premises taken cannot reasonably be carried on with substantially
the same utility and efficiency in the remainder of the Demised Premises (or any
substitute space securable by Tenant pursuant to clause [b] hereof) and (b)
Tenant cannot construct or secure substantially similar space to the space so
taken, on the Demised Premises. Such termination as to the remainder of the
Demised Premises shall be effected by notice in writing given not more than
sixty (60) days after the date of vesting of title in 

                                       51
<PAGE>
 
such Proceedings, and shall specify a date not more than sixty (60) days after
the giving of such notice as the date for such termination. Upon the date
specified in such notice, the Term of this Lease, and all right, title and
interest of Tenant hereunder, shall cease and come to an end. If this Lease is
terminated as in this Section 14.2 provided, Landlord shall be entitled to and
shall receive the total award made in such Proceedings, Tenant hereby assigning
any interest in such award, damages, consequential damages and compensation to
Landlord, and Tenant hereby waiving any right Tenant has now or may have under
present or future law to receive any separate award of damages for its interest
in the Demised Premises, or any portion thereof, or its interest in this Lease
except as otherwise provided in Section 14. 1. The right of Tenant to terminate
this Lease, as in this Section 14.2 provided, shall be exercisable only upon
condition that Tenant is not then in default in the performance of any of the
terms, covenants or conditions of this Lease on its part to be performed, and
such termination upon Tenant's part shall become effective only upon compliance
by Tenant with all such terms, covenants and conditions to the date of such
termination. In the event that Tenant elects not to terminate this Lease as to
the remainder of the Demised Premises, the rights and obligations of Landlord
and Tenant shall be governed by the provisions of Section 14.3 hereof.

     SECTION 14.3 PARTIAL CONDEMNATION/CONTINUATION OF LEASE.

     If twenty-five percent (25%), or less, of the floor area of the Building,
or thirty percent (30%), or less, of the land area of the Demised Premises,
shall be taken in such Proceedings, or if more than twenty-five percent (25%) of
the floor area of the Building or more than thirty percent (30%) of the land
area of the Demised Premises is taken (but less than the entire Demised
Premises), and this Lease is not terminated as in Section 14.2 hereof provided,
this Lease shall, upon vesting of title in the Proceedings, terminate as to the
parts so taken, and Tenant shall have no claim or interest in the award,
damages, consequential damages and compensation, or any part thereof except as
otherwise provided in Section 14.1. Landlord shall be entitled to and shall
receive the total award made in such Proceedings, Tenant hereby assigning any
interest in such award, damages, consequential damages and compensation to
Landlord, and Tenant hereby waiving any right Tenant has now or may have under
present or future law to receive any separate award of damages for its interest
in the Demised Premises, or any portion thereof, or its interest in this Lease
except as otherwise provided in Section 14.1. The net amount of the award (after
deduction of all costs and expenses, including attorneys' fees), shall be paid
to Landlord. Landlord shall, in such case, restore that portion of the
Improvements on the Demised Premises not so taken to a complete architectural
and mechanical unit for the use and occupancy of Tenant as in this Lease
provided. In the event that the net amount of the award (after deduction of all
costs and expenses, including attorneys' fees) that may be received by Landlord
in any such Proceedings for physical damage to the Improvements as a result of
such taking is insufficient to pay all costs of such restoration work, Tenant
shall deposit with Landlord such additional sum as may be required upon the
written request of Landlord.

                                       52
<PAGE>
 
     SECTION 14.4 CONTINUANCE OF OBLIGATIONS.

     In the event of any termination of this Lease, or any part thereof, as a
result of any such Proceedings, Tenant shall pay to Landlord all Basic Rent and
all Additional Rent and other charges payable hereunder with respect to that
portion of the Demised Premises so taken in such Proceedings with respect to
which this Lease shall have terminated justly apportioned to the date of such
termination. From and after the date of vesting of title in such Proceedings,
Tenant shall continue to pay the Basic Rent and Additional Rent and other
charges payable hereunder, as in this Lease provided, to be paid by Tenant,
subject to an abatement of a just and proportionate part of the Basic Rent
according to the extent and nature of such taking as provided for in Sections
14.3 and 14.5 hereof in respect to the Demised Premises remaining after such
taking.

     SECTION 14.5 ADJUSTMENT OF RENT.

     In the event of a partial taking of the Demised Premises under Section 14.3
hereof, or a partial taking of the Demised Premises under Section 14.2 hereof,
followed by Tenant's election not to terminate this Lease, the fixed Basic Rent
payable hereunder during the period from and after the date of vesting of title
in such Proceedings to the termination of this Lease shall be reduced to a sum
equal to the product of the Basic Rent provided for herein multiplied by a
fraction, the numerator of which is the value (as measured by "Market Rent") of
the Demised Premises after such taking and after the same has been restored to a
complete architectural unit, and the denominator of which is the value (as
measured by "Market Rent") of the Demised Premises prior to such taking.


                                   ARTICLE XV
                            ASSIGNMENT AND SUBLETTING

     SECTION 15.1 RESTRICTION ON TRANSFER.

     Otherwise as set forth in this Article XV, Tenant shall not sublet the
Demised Premises, or any portion thereof, nor assign, mortgage, pledge, transfer
or otherwise encumber or dispose of this Lease, or any interest therein, or in
any manner assign, mortgage, pledge, transfer or otherwise encumber or dispose
of its interest or estate in the Demised Premises, or any portion thereof, by
operation of law or otherwise, without obtaining Landlord's prior written
consent in each and every instance, which consent may be withheld in Landlord's
sole, unfettered discretion.

     SECTION 15.2 SUBLEASE REQUIREMENTS.

                                       53
<PAGE>
 
     However, Tenant may sublet up to a cumulative total of fifty percent (50%)
of the Demised Premises, by first obtaining Landlord's prior written consent,
which consent shall not be withheld or delayed provided that the following
conditions are complied with:

     (i) At the time of any subletting, and at the time when Tenant requests
Landlord's written consent thereto, this Lease must be in full force and effect,
without any uncured breach or Event of Default thereunder on the part of Tenant.

     (ii) Any such sublessee shall assume, by written, recordable instrument,
the due performance of all of Tenant's obligations under this Lease with respect
to the sublet Demised Premises, including any accrued obligations at the time of
the effective date of the sublease, and such assumption agreement shall state
that the same is made by the sublessee for the express benefit of Landlord as a
third party beneficiary thereof so that Landlord may proceed directly against
the sublessee in the event a breach of the assumption agreement.

     (iii) Such subletting shall be subject to all the provisions, terms,
covenants and conditions of this Lease, and Tenant shall continue to be and
remain liable under the Lease.

     (iv) Tenant agrees to pay on behalf of Landlord any and all reasonable
costs of Landlord, including attorneys' fees paid or payable to outside counsel,
occasioned by a review of any such sublease, not to exceed One Thousand Dollars
($1,000.00) per sublease.

     (v) Such sublessee must be of a business character which Landlord
reasonably finds to be consistent with the character of other tenants in the
Bass Creek Business Park on the date of this Lease.

     (vi) No such sublessee shall have any rights under Article XXIII hereof. A
purchaser of substantially all of the assets of the Tenant shall have all of the
rights of Tenant under Article XXIII.

     SECTION 15.3 SUBLESSEE MAINTENANCE REQUIREMENTS.

     In the event that Tenant proposes to sublease a cumulative total of more
than fifty percent (50%) of the Demised Premises, then, in addition to
satisfying the requirements in Section 15.2:

     (i) the Tenant shall submit a "Maintenance and Repair Report" (as herein
     defined) to Landlord within thirty (30) days of each annual anniversary of
     such sublease. A "Maintenance and Repair Report" is a report prepared by an
     engineering firm selected by Landlord, and reasonably acceptable to Tenant,

                                       54
<PAGE>
 
     which reports on whether the Demised Premises are being maintained and
     repaired in a manner consistent with the requirements of this Lease. The
     Maintenance and Repair Report will be paid for by Tenant. If the
     Maintenance and Repair Report discloses deficiencies with respect to such
     maintenance or repair (the "Deficiencies"), Tenant shall, within thirty
     (30) days, correct such Deficiencies, at its cost. Any such Deficiencies
     not corrected, to the satisfaction of the engineer preparing the
     Maintenance and Repair Report, may, following an additional five (5) days
     notice be corrected by Landlord and all costs incurred by Landlord with
     respect thereto, together with interest at the Maximum Rate of Interest,
     will be immediately paid by Tenant and will constitute Additional Rent due
     hereunder; and

     (ii) Tenant's right to expand the Demised Premises (as set forth in Article
     XXIII), Tenant's right to extend the Term (as set forth in Article XXII)
     and Tenant's rights under the Agreement Regarding Excess Land of even date
     herewith between the Landlord and the Tenant shall terminate.

     SECTION 15.4 RESTRICTION FROM FURTHER ASSIGNMENT.

     Notwithstanding any consent by Landlord to any sublease of the Demised
Premises, or any portion thereof, no sublessee shall assign its sublease nor
further sublease the Demised Premises, or any portion thereof, without
Landlord's prior written consent in each and every instance which consent may be
withheld in Landlord's sole discretion. No such subleasing shall relieve Tenant
from any of its obligations hereunder.

     SECTION 15.5 TENANT'S FAILURE TO COMPLY.

     Tenant's failure to comply with all of the provisions of this Article XV
shall (whether or not Landlord's consent is required under this Article), at
Landlord's option, render any purported assignment or subletting null and void
and of no force and effect.

     SECTION 15.6 ACQUISITION OF TENANT.

     Notwithstanding the foregoing provisions of this Article XV, in the event
that substantially all of the Tenant's assets are acquired by a third party, and
provided there is no Event of Default hereunder, this Lease may be assigned to
that third party, provided that said thirty party assumes all of the obligations
of the Tenant hereunder and further provided that Tenant will not be released of
its obligations hereunder by reason of such assignment. The documentation
pursuant to which that third party assumes the Tenant's obligations hereunder
shall be reasonably acceptable to Landlord and shall provide for enforcement, by
Landlord, of the obligations of that third party.

                                       55
<PAGE>
 
                                   ARTICLE XVI
                         SUBORDINATION, NONDISTURBANCE,
                       NOTICE TO MORTGAGEE AND ATTORNMENT

     SECTION 16.1 SUBORDINATION BY TENANT.

     This Lease and all rights of Tenant therein, and all interest or estate of
Tenant in the Demised Premises, or any portion thereof, including all expansion
and renewal rights, shall be subject and subordinate to the lien of any
mortgage, deed of trust, security instrument or other document of like nature
("Mortgage"), which at any time may be placed upon the Demised Premises, or any
portion thereof, by Landlord, and to any replacements, renewals, amendments,
modifications, extensions or refinancing thereof, and to each and every advance
made under any Mortgage. Tenant agrees at any time hereafter, and from time to
time on demand of Landlord, in connection with a sale or refinancing of the
Demised Premises or at the request of the holder or proposed holder of the
Mortgage to execute and deliver to Landlord any instruments, releases or other
documents that may be reasonably required for the purpose of subjecting and
subordinating this Lease and said rights of Tenant to the lien of any such
Mortgage, which such documents are to be reasonably acceptable to the Landlord,
the Tenant and the holder of the Mortgage. It is agreed, nevertheless, that so
long as Tenant is not in default in the payment of Basic Rent and Additional
Rent and the performance and observance of all covenants, conditions,
provisions, terms and agreements to be performed and observed by Tenant under
this Lease, that such subordination agreement or other instrument, release or
document shall contain non-disturbance provisions pursuant to which the holder
of the Mortgage agrees not to interfere with, hinder or molest Tenant's right to
quiet enjoyment under this Lease, nor the right of Tenant to continue to occupy
the Demised Premises, and all portions thereof, and to conduct its business
thereon in accordance with the covenants, conditions, provisions, terms and
agreements of this Lease. The lien of any such Mortgage shall not cover Tenant's
trade fixtures or other personal property located in or on the Demised Premises.

     Tenant agrees to give any holder of any Mortgage, by registered or
certified mail, a copy of any notice or claim of default served upon Landlord by
Tenant, provided that prior to such notice, Tenant has been notified in writing,
by way of service on Tenant of a copy of an assignment of Landlord's interests
in leases, or otherwise, of the address of such Mortgage holder.

     SECTION 16.2 LANDLORD'S DEFAULT.

     In the event of any act or omission of Landlord constituting a default by
Landlord, Tenant shall not exercise any remedy until Tenant has given Landlord
and the holder of any Mortgage (as provided for in Section 16.1) prior written
notice of such act or omission and until a thirty (30)-day period of time to
allow Landlord or the 

                                       56
<PAGE>
 
mortgagee to remedy such act or omission shall have elapsed following the giving
of such notice; provided, however, if such act or omission cannot, with due
diligence and in good faith, be remedied within such thirty (30)-day period, the
Landlord and/or mortgagee shall be allowed such further period of time as may be
reasonably necessary provided that it shall have commenced remedying the same
with due diligence and in good faith within said thirty (30)-day period. In the
event Landlord's act or omission which constitutes a Landlord's default
hereunder results in an immediate threat of bodily harm to Tenant's employees,
agents or invitees, or damage to Tenant's property Tenant may proceed to cure
the default without prior notice to Landlord provided, however, in that event
Tenant shall give written notice to Landlord as soon as possible after
commencement of such cure. Landlord will reimburse Tenant for any reasonable
out-of-pocket expenses incurred by Tenant in effecting such cure, provided that
Tenant has given Landlord at least fifteen (15) additional days' notice of its
intention to expend such sums. Nothing herein contained shall be construed or
interpreted as requiring any mortgagee to remedy such act or omission.

     SECTION 16.3 ATTORNMENT.

     If any mortgagee shall succeed to the rights of Landlord under this Lease
or to ownership of the Demised Premises, whether through possession or
foreclosure or the delivery of a deed to the Demised Premises, then, upon the
written request of such mortgagee so succeeding to Landlord's rights hereunder,
Tenant shall attorn to and recognize such mortgagee as Tenant's landlord under
this Lease, and shall promptly execute and deliver any instrument that such
mortgagee may reasonably request to evidence such attornment (whether before or
after making of the mortgage). In the event of any other transfer of Landlord's
interest hereunder, upon the written request of the transferee and Landlord,
Tenant shall attorn to and recognize such transferee as Tenant's landlord under
this Lease and shall promptly execute and deliver any instrument that such
transferee and Landlord may reasonably request to evidence such attornment.
Reference is made to Section 20.6 for the provisions regarding Landlord's
liability following such transfer of Landlord's interest.

     It is further agreed that (a) if any Mortgage shall be foreclosed, (i) the
holder of the Mortgage, ground lessor (or their respective grantees) or
purchaser at any foreclosure sale (or grantee in a deed in lieu of foreclosure),
as the case may be, shall not be (x) liable for any act or omission of any prior
landlord (including Landlord), (y) subject to any offsets or counterclaims which
Tenant may have against a prior landlord (including Landlord), or (z) bound by
any prepayment of Basic Rent or Additional Rent which Tenant may have made in
excess of the amounts then due for the next succeeding month, (ii) the liability
of the mortgagee or trustee hereunder or purchaser at such foreclosure sale or
the liability of a subsequent owner designated as Landlord under this Lease
shall exist only so long as such trustee, mortgagee, purchaser or owner of the
Demised Premises and such liability shall not continue or survive after further
transfer of ownership.

                                       57
<PAGE>
 
                                  ARTICLE XVII
                                      SIGNS

     SECTION 17.1 TENANT'S SIGNS.

     Tenant may erect signs on the exterior or interior of the Building or on
the landscaped area adjacent thereto, provided that such sign or signs (a) do
not cause any structural damage or other damage to the Building; (b) do not
violate applicable governmental laws, ordinances, rules or regulations; (c) do
not violate any existing covenants, conditions or restrictions affecting the
Demised Premises; (d) are compatible with the architecture of the Building and
the landscaped area adjacent thereto; and (e) are approved by Landlord in its
reasonable discretion. Tenant shall not be permitted to install signage on the
roof of the Building.

                                  ARTICLE XVIII
                                REPORTS BY TENANT

     SECTION 18.1 ANNUAL STATEMENTS.

     Upon request by Landlord at any time after one hundred thirty-five (135)
days after the end of the applicable fiscal year of Tenant, Tenant shall deliver
to Landlord (within fifteen (15) days after receipt of written request) a copy
of its most recently published, audited financial statement (including, but not
limited to, an audited balance sheet, if available, and an income statement),
including the certification of its auditor, and similar financial statement of
any guarantor of Tenant's obligations under this Lease.

                                   ARTICLE XIX
                             CHANGES AND ALTERATIONS

     SECTION 19.1 TENANT'S CHANGES AND ALTERATIONS.

     Subject to the Landlord's prior written consent, which consent shall not be
unreasonably withheld or delayed, Tenant shall have the right at any time, and
from time to time during the Term of this Lease, to make such changes and
alterations, structural or otherwise, to the Building, improvements and fixtures
hereafter erected on the Demised Premises as Tenant shall deem necessary or
desirable in connection with the requirements of its business, which such
changes and alterations (other than changes or alterations of Tenant's movable
trade fixtures and equipment) shall be made in all cases subject to the
following conditions, which Tenant covenants to observe and perform:

                                       58
<PAGE>
 
     (a)  Permits. No change or alteration shall be undertaken until Tenant
          shall have procured and paid for, so far as the same may be required
          from time to time, all municipal, state and federal permits and
          authorizations of the various governmental bodies and departments
          having jurisdiction thereof, and Landlord agrees to join in the
          application for such permits or authorizations whenever such action is
          necessary, all at Tenant's sole cost and expense, provided such
          applications do not cause Landlord to become liable for any cost, fees
          or expenses.

     (b)  Compliance with Plans and Specifications. Before commencement of any
          change, alteration, restoration or construction (hereinafter sometimes
          referred to as "Alterations") which will cause Two Hundred Fifty
          Thousand ($250,000.00) Dollars or more to be spent on Alterations
          during any twelve (12) month period, or which in Landlord's reasonable
          judgment would materially alter the mechanical, structural,
          electrical, plumbing, or fire/life safety systems of the Improvements,
          separately referred to as a "Structural Alteration" shall (i) furnish
          Landlord with detailed plans and specifications of the proposed
          Structural Alteration or Alteration; (ii) obtain Landlord's prior
          written consent, which consent shall not be unreasonably withheld (but
          such consent may be withheld if the Alteration or Structural
          Alteration would, in the reasonable judgment of Landlord, impair the
          value or usefulness of the Land or Improvements, or any substantial
          part thereof to Landlord); (iii) obtain Landlord's prior written
          approval of a licensed architect or licensed professional engineer
          selected and paid for by Tenant, who shall supervise any such work
          (hereinafter referred to as "Alterations Architect or Engineer"); (iv)
          obtain Landlord's prior written approval of detailed plans and
          specifications prepared and approved in writing by said Alterations
          Architect or Engineer, and of each amendment and change thereto; and
          (v) furnish to Landlord a surety company performance bond issued by a
          surety company licensed to do business in the state in which the
          Demised Premises are located and reasonably acceptable to Landlord in
          an amount equal to the estimated cost of such work guaranteeing the
          completion thereof within a reasonable time thereafter (1) free and
          clear of all mechanic's liens or other liens, encumbrances, security
          interests and charges, and (2) in accordance with the plans and
          specifications approved by Landlord. All Structural Alterations shall
          be performed by Landlord at the cost of Tenant.

     (c)  Value Maintained. Any change or alteration shall, when completed, be
          of such character as not to reduce the value or utility of the Demised
          Premises or the Building below its value or utility to Landlord
          immediately before such change or alteration, nor shall such change or

                                       59
<PAGE>
 
          alteration reduce or enlarge the area or cubic content of the
          Building, nor change the character of the Demised Premises or the
          Building as to use without Landlord's express written consent.

     (d)  Compliance with Laws. All work done in connection with any change or
          alteration shall be done promptly and in a good and workmanlike manner
          and in compliance with all building and zoning laws of the place in
          which the Demised Premises are situated, and with all laws,
          ordinances, orders, rules, regulations and requirements of all
          federal, state and municipal governments and appropriate departments,
          commissions, boards and officers thereof, and in accordance with the
          orders, rules and regulations of the Board of Fire Underwriters where
          the Demised Premises are located, or any other body exercising similar
          functions, and in accordance and not in violation of all easements,
          restrictions, reservations and other encumbrances now or hereafter
          recorded against the Land. The cost of any such change or alteration
          shall be paid in cash so that the Demised Premises and all portions
          thereof shall at all times be free of liens for labor and materials
          supplied to the Demised Premises, or any portion thereof. The Work
          shall be prosecuted with reasonable dispatch, delays due to strikes,
          lockouts, acts of God, inability to obtain labor or materials,
          governmental restrictions or similar causes beyond the control of
          Tenant excepted. Tenant shall obtain and maintain, at its sole cost
          and expense, during the performance of the Work, workers' compensation
          insurance covering all persons employed in connection with the Work
          and with respect to which death or injury claims could be asserted
          against Landlord or Tenant or against the Demised Premises or any
          interest therein, together with comprehensive general liability
          insurance for the mutual benefit of Landlord and Tenant with limits of
          not less than One Million Dollars ($1,000,000.00) in the event of
          injury to one person, Three Million Dollars ($3,000,000.00) in respect
          to any one accident or occurrence, and Five Hundred Thousand Dollars
          ($500,000.00) for property damage, and the fire insurance with
          "extended coverage" endorsement required by Section 6.1 hereof shall
          be supplemented with "builder's risk" insurance on a completed value
          form or other comparable coverage on the Work. All such insurance
          shall be in a company or companies authorized to do business in the
          state in which the Demised Premises are located and reasonably
          satisfactory to Landlord, and all such policies of insurance or
          certificates of insurance shall be delivered to Landlord endorsed
          "Premium Paid" by the company or agency issuing the same, or with
          other evidence of payment of the premium satisfactory to Landlord.

                                       60
<PAGE>
 
     (e)  Property of Landlord. All improvements and alterations (other than
          Tenant's movable trade fixtures and equipment) made or installed by
          Tenant shall immediately, upon completion or installation thereof,
          become the property of Landlord without payment therefor by Landlord,
          and shall be surrendered to Landlord on the expiration of the Term of
          this Lease, subject to Section 19.1(g) herein.

     (f)  Location of Improvements. No change, alteration, restoration or new
          construction shall be in or connect the Improvements with any
          property, building or other improvement located outside the boundaries
          of the Land, nor shall the same obstruct or interfere with any
          existing easement.

     (g)  Removal of Improvements. As a condition to granting approval for any
          Alterations, Landlord may require Tenant to agree that Landlord, by
          written notice to Tenant, given at or prior to the time of granting
          such approval, may require Tenant to remove any improvements,
          additions or installations installed by Tenant in the Demised Premises
          at Tenant's sole cost and expense, and repair and restore any damage
          caused by the installation and removal of such improvements,
          additions, or installations; provided, however, the only improvements,
          additions or installations which Tenant shall remove shall be those
          specified in such notice. All improvements, additions or installations
          installed by Tenant which did not require Landlord's prior approval
          shall be removed by Tenant as provided in this Section 19.1(g), unless
          Tenant has obtained a written waiver of such condition from Landlord.

     (h)  Written Notification Required. Tenant shall notify Landlord in writing
          thirty (30) days prior to commencing any alterations, additions or
          improvements to the Demised Premises which have been approved by
          Landlord so that Landlord shall have the right to record and post
          notices of non-responsibility on the Demised Premises.


                                   ARTICLE XX
                            MISCELLANEOUS PROVISIONS

     SECTION 20.1 ENTRY BY LANDLORD.

     Tenant agrees to permit Landlord and authorized representatives of Landlord
to enter upon the Demised Premises at all reasonable times during ordinary
business hours for the purpose of inspecting the same and making any necessary
repairs to comply with any laws, ordinances, rules, regulations or requirements
of any public body, or the Board of Fire Underwriters, or any similar body,
provided Tenant shall first have 

                                       61
<PAGE>
 
been given notice of Landlord's intention to do so and shall have failed to
complete said repairs within thirty (30) days following such notice. Nothing
herein contained shall imply any duty upon the part of Landlord to do any such
work which, under any provision of this Lease, Tenant may be required to perform
and the performance thereof by Landlord shall not constitute a waiver of
Tenant's default in failing to perform the same. Landlord may, during the
progress of any work, keep and store upon the Demised Premises all necessary
materials, tools and equipment. Landlord shall not in any event be liable for
inconvenience, annoyance, disturbance, loss of business or other commercially
unreasonable damage to Tenant by reason of making repairs or the performance of
any work in or about the Demised Premises, or on account of bringing material,
supplies and equipment into, upon or through the Demised Premises during the
course thereof, and the obligations of Tenant under this Lease shall not be
thereby affected in any manner whatsoever. In effecting such repairs, the
Landlord will not unreasonably interfere with the Tenant's use of the Demised
Premises.

     SECTION 20.2 EXHIBITION OF DEMISED PREMISES.

     Landlord is hereby given the right during usual business hours at any time
during the final eighteen (18) months of the Term of this Lease (as it may have
been extended) to enter upon the Demised Premises and to exhibit the same for
the purpose of mortgaging, leasing or selling the same. During the final year of
the Term, Landlord shall be entitled to display on the Demised Premises, in such
manner as to not unreasonably interfere with Tenant's business, signs indicating
that the Demised Premises are for rent or sale and suitably identifying Landlord
or its agent. Tenant agrees that such signs may remain unmolested upon the
Demised Premises.

     SECTION 20.3 INDEMNIFICATION BY TENANT.

     The occurrence of any event for which Tenant is required to indemnify
Landlord under the terms of this Lease shall be referred to in this Section 20.3
as an "Indemnity Event". Landlord agrees that, within sixty (60) days of the
date that Landlord discovers the existence of an Indemnity Event, Landlord shall
make a commercially reasonable effort to notify Tenant of the Indemnity Event.
Landlord's failure to so notify Tenant, however, will not impair Landlord's
right to assert a claim against Tenant for an Indemnity Event. In the event any
action or proceeding be brought against Landlord by reason of any Indemnity
Event, Tenant shall, at its sole cost and expense, defend such proceeding by
counsel reasonably satisfactory to Landlord. Tenant shall make no settlement of
such an action without Landlord's consent and Tenant shall cooperate with
Landlord's reasonable efforts to participate in defense strategy relative to
such an action.

     To the fullest extent allowed by law, Tenant shall at all times indemnify,
defend and hold harmless Landlord and Landlord's shareholders, employees and
managing 

                                       62
<PAGE>
 
agent against and from any and all claims, costs, liabilities, actions and
damages (including, without limitation, attorneys' fees and costs) by or on
behalf of any person or persons, firm or firms, corporation or corporations,
arising from the conduct or management, or from any work or things whatsoever
done in or about the Demised Premises (other than the construction of the
Landlord's Improvements and the Tenant Improvements), and will further
indemnify, defend and hold harmless Landlord against and from any and all claims
arising during the Term of this Lease, from any condition of the Demised
Premises or any street, curb or sidewalk adjoining the Demised Premises, or of
any passageways or space therein or appurtenant thereto, or arising from any
breach or default on the part of Tenant in the performance of any covenant or
agreement on the part of Tenant to be performed, pursuant to the terms of this
Lease, or arising from any act or negligence of Tenant, its agents, servants,
employees or licensees, or arising from any accident, injury or damage
whatsoever caused to any person, firm or corporation occurring during the Term
of this Lease, in or about the Demised Premises, or upon the sidewalk and the
land adjacent thereto, and from and against all costs, attorneys' fees, expenses
and liabilities incurred in or about any such claim or action or proceeding
brought thereon; and in case any action or proceeding be brought against
Landlord by reason of any such claim, Tenant, upon notice from Landlord,
covenants to defend such action or proceeding by counsel reasonably satisfactory
to Landlord. Tenant's obligations under this Section 20.3 shall be insured by
contractual liability endorsement on Tenant's policies of insurance required
under the provisions of Section 6.2 hereof.

     SECTION 20.4 NOTICES.

     All notices, demands and requests which may be or are required to be given,
demanded or requested by either party to the other shall be in writing. All
notices, demands and requests shall be sent by United States registered or
certified mail, postage prepaid or by an independent overnight courier service,
addressed as follows:

                  To Tenant:              Computer Network
                                            Technology Corporation
                                          605 North Highway 169
                                          Suite 800
                                          Minneapolis, MN 55441
                                          Attn: Greg Barnum,
                                          Chief Financial Officer

                                          Until January 1, 1999
                                          ---------------------
                  To Landlord:            Opus Northwest, L.L.C.
                                          700 Opus Center
                                          9900 Bren Road East
                                          Minnetonka, MN 55343

                                       63
<PAGE>
 
                  With a Copy to:         Opus U.S. Corporation
                                          9900 Bren Road East
                                          800 Opus Center
                                          Minnetonka, MN 55343
                                          Attn:  Legal Department

                                          After January 1, 1999
                                          ---------------------
                  To Landlord:            Opus Northwest, L.L.C.
                                          10350 Bren Road West
                                          Minnetonka, MN 55343

                  With a Copy to:         Opus U.S. Corporation
                                          10350 Bren Road West
                                          Minnetonka, MN 55343
                                          Attn:  Legal Department


or at such other place as either party may from time to time designate by
written notice to the other. Notices, demands and requests which are served upon
Landlord by Tenant, or upon Tenant by Landlord, in the manner aforesaid, shall
be deemed to be sufficiently served or given for all purposes hereunder on the
date which is two (2) days after the time such notice, demand or request shall
be mailed or on the date on which such notice, demand or request is delivered to
a courier.

     SECTION 20.5 QUIET ENJOYMENT.

     Landlord covenants and agrees that Tenant, upon paying the Basic Rent and
Additional Rent, and upon observing and keeping the covenants, agreements and
conditions of this Lease on its part to be kept, observed and performed, shall
lawfully and quietly hold, occupy and enjoy the Demised Premises (subject to the
provisions of this Lease) during the Term of this Lease without hindrance or
molestation by Landlord or by any person or persons claiming under Landlord.

     SECTION 20.6 LANDLORD'S CONTINUING OBLIGATIONS.

     The term "Landlord", as used in this Lease so far as covenants or
obligations on the part of Landlord are concerned, shall be limited to mean and
include only the owner or owners at the time in question of the fee of the
Demised Premises, and in the event of any transfers or conveyance, the then
grantor shall be automatically freed and relieved from and after the date of
such transfer or conveyance of all liability as respects the performance of any
covenants or obligations on the part of Landlord contained in this Lease
thereafter to be performed, provided: (i) that any funds in the hands of such
landlord or the then grantor at the time of such transfer, in which Tenant has
an interest, shall be turned over to the grantee; (ii) any amount then
unconditionally due and payable to Tenant by Landlord or the then grantor under
any provision of this 

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Lease shall be paid to Tenant; and (iii) the Landlord named herein will not be
relieved of liability for any past or future breach of (a) the one (1) year
guaranty specified in Section 2.8 herein, (b) any responsibility of Landlord for
the cost of compliance with Hazardous Materials Laws specified in Sections 9.6
and 9.7 herein, and (c) responsibility for compliance with the ADA as specified
in Section 9.12 herein. Furthermore, the obligations set forth in the foregoing
subsection (iii), all of which are personal to the Landlord named herein, shall
not be binding on Landlord's successors and assigns. The covenants and
obligations contained in this Lease on the part of Landlord shall, subject to
the aforesaid, be binding on Landlord's successors and assigns, during and in
respect of their respective successive periods of ownership. Nothing herein
contained shall be construed as releasing Landlord from any obligation to
complete the cure of any breach by Landlord during the period of its ownership
of the Demised Premises.

     SECTION 20.7 ESTOPPEL.

     Landlord and Tenant shall, each without charge at any time and from time to
time, within fifteen (15) days after written request by the other party, certify
by written instrument, duly executed, acknowledged and delivered to any
mortgagee, assignee of a mortgagee, proposed mortgagee, or to any purchaser or
proposed purchaser, or to any other person dealing with Landlord, Tenant or the
Demised Premises:

     (a)  That this Lease (and all guaranties, if any) is unmodified and in full
          force and effect (or, if there have been modifications, that the same
          is in full force and effect, as modified, and stating the
          modifications);

     (b)  The dates to which the Basic Rent or Additional Rent have been paid in
          advance;

     (c)  Whether or not there are then existing any breaches or defaults by
          such party or the other party known by such party under any of the
          covenants, conditions, provisions, terms or agreements of this Lease,
          and specifying such breach or default, if any, or any setoffs or
          defenses against the enforcement of any covenant, condition,
          provision, term or agreement of this Lease (or of any guaranties, if
          any) upon the part of Landlord or Tenant (or any guarantor, if any),
          as the case may be, to be performed or complied with (and, if so,
          specifying the same and the steps being taken to remedy the same);

     (d)  Such other statements or certificates as Landlord or any mortgagee may
          reasonably request.

     It is the intention of the parties hereto that any statement delivered
pursuant to this Section 20.7 may be relied upon by any of such parties dealing
with Landlord, 

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<PAGE>
 
Tenant or the Demised Premises. If Tenant does not deliver such statement to
Landlord within such fifteen (15) day period, Landlord, and any prospective
purchaser or encumbrancer of the Demised Premises or the Building, may
conclusively presume and rely upon the following facts: (i) that the terms and
provisions of this Lease have not been changed except as otherwise represented
by Landlord; (ii) that this Lease has not been canceled or terminated and is in
full force and effect, except as otherwise represented by Landlord; (iii) that
the current amounts of the Basic Rent is as represented by Landlord; (iv) that
there have been no subleases or assignments of the Lease; (v) that not more than
one month's Basic Rent or other charges have been paid in advance; and (vi) that
Landlord is not in default under the Lease. In such event, Tenant shall be
estopped from denying the truth of such facts.

     SECTION 20.8 DELIVERY OF CORPORATE DOCUMENTS.

     In the event that Tenant is a corporation, Tenant shall, without charge to
Landlord, at any time and from time to time within ten (10) days after written
request by Landlord, deliver to Landlord, in connection with any proposed sale
or mortgage of the Demised Premises, the following instruments and documents: a
certification that this Lease has been duly authorized by all necessary
corporate action and is a valid and binding agreement enforceable in accordance
with its terms.

                  SECTION 20.9 MEMORANDUM OF LEASE.

     Upon not less than fifteen (15) days prior written request by either party,
the parties hereto agree to execute and deliver to each other a Memorandum of
Lease, in recordable form, setting forth the date of this Lease, the parties to
this Lease, the Term of this Lease, the legal description of the Demised
Premises, and such other matters reasonably requested by Landlord to be stated
therein.

     SECTION 20.10 SEVERABILITY.

     If any covenant, condition, provision, term or agreement of this Lease
shall, to any extent, be held invalid or unenforceable, the remaining covenants,
conditions, provisions, terms and agreements of this Lease shall not be affected
thereby, but each covenant, condition, provision, term or agreement of this
Lease shall be valid and in force to the fullest extent permitted by law.

     SECTION 20.11 SUCCESSORS AND ASSIGNS.

     The covenants and agreements herein contained shall bind and inure to the
benefit of Landlord and its successors and assigns and Tenant and its permitted
successors and assigns. Reference is made to Section 20.31 regarding provisions
controlling Landlord's right to assign its interest herein.

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<PAGE>
 
     SECTION 20.12 CAPTIONS.

     The caption of each article of this Lease is for convenience and reference
only, and in no way defines, limits or describes the scope or intent of such
article or of this Lease.

     SECTION 20.13 RELATIONSHIP OF PARTIES.

     This Lease does not create the relationship of principal and agent, or of
partnership, joint venture, or of any association or relationship between
Landlord and Tenant, the sole relationship between Landlord and Tenant being
that of landlord and tenant, which relationship includes certain provisions in
the Agreement Regarding Excess Land of even date herewith and certain provisions
regarding the expansion of the Demised Premises in Article XXIII.

     SECTION 20.14 ENTIRE AGREEMENT.

     All preliminary and contemporaneous negotiations are merged into and
incorporated in this Lease. This Lease, together with the Exhibits attached
hereto, contains the entire agreement between the parties and shall not be
modified or amended in any manner except by an instrument in writing executed by
the parties hereto.

     SECTION 20.15 NO MERGER.

     There shall be no merger of this Lease or the leasehold estate created by
this Lease with any other estate or interest in the Demised Premises by reason
of the fact that the same person, firm, corporation or other entity may acquire,
hold or own directly or indirectly, (a) this Lease or the leasehold interest
created by this Lease or any interest therein, and (b) any such other estate or
interest in the Demised Premises, or any portion thereof. No such merger shall
occur unless and until all persons, firm, corporations or other entities having
an interest (including a security interest) in (1) this Lease or the leasehold
estate created thereby, and (2) any such other estate or interest in the Demised
Premises, or any portion thereof, shall join in a written instrument expressly
effecting such merger and shall duly record the same.

     SECTION 20.16 POSSESSION AND USE.

     Tenant acknowledges that the Demised Premises are the property of Landlord
and that Tenant has only the right to possession and use thereof upon the
covenants, conditions, provisions, terms and agreements set forth in this Lease.

     SECTION 20.17 NO SURRENDER DURING LEASE TERM.

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<PAGE>
 
     No surrender to Landlord of this Lease or of the Demised Premises, or any
portion thereof, or any interest therein, prior to the expiration of the Term of
this Lease shall be valid or effective unless agreed to and accepted in writing
by Landlord and consented to in writing by all contract vendors and mortgagees,
and no act or omission by Landlord or any representative or agent of Landlord,
other than such a written acceptance by Landlord consented to by all contract
vendors and the mortgagees, as aforesaid, shall constitute an acceptance of any
such surrender.

     SECTION 20.18 SURRENDER OF DEMISED PREMISES.

     At the expiration of the Term of this Lease, Tenant shall surrender the
Demised Premises in the same condition as the same were in upon delivery of
possession thereto at the Commencement Date of the Term of this Lease,
reasonable wear and tear and (subject to the provisions of Article XIII) damages
on account of casualty loss excepted, and shall surrender all keys to the
Demised Premises to Landlord at the place then fixed for the payment of Basic
Rent and shall inform Landlord of all combinations on locks, safes and vaults,
if any. Tenant shall at such time remove all of its property therefrom and all
alterations and improvements placed thereon by Tenant, subject to Section
19.1(g). Tenant shall not remove the Tenant Improvements or any cabling
installed by Tenant. Tenant shall repair any damage to the Demised Premises
caused by such removal, and any and all such property not so removed shall, at
Landlord's option, become the exclusive property of Landlord or be disposed of
by Landlord, at Tenant's cost and expense, without further notice to or demand
upon Tenant. If the Demised Premises be not surrendered as above set forth,
Tenant shall indemnify, defend and hold harmless Landlord against loss or
liability resulting from the delay by Tenant in so surrendering the Demised
Premises, including, without limitation any claim made by any succeeding
occupant founded on such delay. Tenant's obligation to observe or perform this
covenant shall survive the expiration or other termination of this Lease.

     All property of Tenant not removed within ten (10) days after demand by
Landlord, which notice cannot be given until after the last day of the Term of
this Lease shall be deemed abandoned. Tenant hereby appoints Landlord its agent
to remove all property of Tenant from the Demised Premises upon termination of
this Lease and to cause its transportation and storage for Tenant's benefit, all
at the sole cost and risk of Tenant and Landlord shall not be liable for damage,
theft, misappropriation or loss thereof and Landlord shall not be liable in any
manner in respect thereto. Tenant shall pay all costs and expenses of such
removal, transportation and storage. Tenant shall reimburse Landlord upon demand
for any expenses incurred by Landlord with respect to removal or storage of
abandoned property and with respect to restoring said Demised Premises to good
order, condition and repair.

     SECTION 20.19 HOLDING OVER.

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<PAGE>
 
     In the event Tenant remains in possession of the Demised Premises after
expiration of this Lease, and without the execution of a new lease, it shall be
deemed to be occupying the Demised Premises as a tenant from month to month,
subject to all the provisions, conditions and obligations of this Lease insofar
as the same can be applicable to a month-to-month tenancy, except that the Basic
Rent shall be escalated to one hundred fifty percent (150%) of the then current
Basic Rent for the Demised Premises.

     SECTION 20.20 LANDLORD APPROVALS.

     Any approval by Landlord or Landlord's architects and/or engineers of any
of Tenant's drawings, plans and specifications which are prepared in connection
with any construction of improvements respecting the Demised Premises shall not
in any way be construed or operate to bind Landlord or to constitute a
representation or warranty of Landlord as to the adequacy or sufficiency of such
drawings, plans and specifications, or the improvements to which they relate,
for any reason, purpose or condition, but such approval shall merely be the
consent of Landlord, as may be required hereunder, in connection with Tenant's
construction of improvements relating to the Demised Premises in accordance with
such drawings, plans and specifications.

     SECTION 20.21 SURVIVAL.

     All obligations (together with interest or money obligations at the Maximum
Rate of Interest) accruing prior to expiration of the Term of this Lease shall
survive the expiration or other termination of this Lease.

     SECTION 20.22 ATTORNEYS' FEES.

     In the event of any litigation or judicial action in connection with this
Lease or the enforcement thereof, the prevailing party in any such litigation or
judicial action shall be entitled to recover all costs and expenses of any such
judicial action or litigation (including, but not limited to, reasonable
attorneys' fees and paralegals' fees) from the other party.

     SECTION 20.23 LANDLORD'S LIMITED LIABILITY.

     Tenant agrees to look solely to Landlord's interest in the Demised Premises
for recovery of any judgment from Landlord, it being agreed that Landlord (and
if Landlord is a partnership, its partners, whether general or limited, and if
Landlord is a corporation, its directors, officers or shareholders) shall never
be personally liable for any personal judgment or deficiency decree or judgment
against it.

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<PAGE>
 
     SECTION 20.24 BROKER.

     Tenant represents that Tenant has dealt with Braman, Braman & Rekstad Inc.
(being Tenant's consultant) as brokers, in connection with the transaction of
which this Lease is a part and that no other consultant or broker has negotiated
or participated in negotiations of that transaction or this Lease or submitted
or showed the Demised Premises or is entitled to any commission in connection
therewith. Landlord has dealt with no broker other than Tenant's Consultant and
will indemnify and hold Tenant harmless from and against any commissions, fees
and expense, or claims therefor by any consultant, broker, salesman, or other
party in connection with or arising out of Landlord's action in connection
therewith. Tenant shall indemnify and hold Landlord harmless from and against
any and all commissions, fees and expenses and all claims therefor, by any
consultant or broker, salesman or other party in connection with or arising out
of Tenant's action in entering into that transaction or this Lease, other than
the commission due to Braman, Braman & Rekstad Inc. which commission, in the
amount of $457,312.00, will be paid by Landlord, said payment to be made as
follows: (i) $228,656.00 to be paid upon execution hereof, and (ii) $228,656.00
to be paid within two (2) days of the date on which Tenant pays the first
installment of Basic Rent to Landlord.

     SECTION 20.25 GOVERNING LAW.

     This Lease shall be governed by the laws of the State of Minnesota. All
covenants, conditions and agreements of Tenant arising hereunder shall be
performable in the county wherein the Demised Premises are located. Any suit
arising from or relating to this Lease shall be brought in the county wherein
the Demised Premises are located, and the parties hereto waive the right to be
sued elsewhere.

     SECTION 20.26 "INTENTIONALLY OMITTED."

     SECTION 20.27 TIME IS OF THE ESSENCE.

     Time is of the essence with respect to the performance of every provision
of this Lease in which time of performance is a factor.

     SECTION 20.28 LIMITED RIGHT OF SET OFF.

     In the event that the Landlord does not pay the Tenant the Moving Allowance
or the fee due to Braman, Braman & Rekstad Inc. (as referenced in Section 20.24)
as and when due, the Tenant may, following ten (10) days written notice to
Landlord, deduct said unpaid amounts from the Basic Rent next coming due
hereunder.

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<PAGE>
 
     SECTION 20.29 TIME PERIOD FOR CLAIMS.

     Any claim which either party may have against the other for default in
performance of any of the obligations herein contained to be kept and performed
by the other shall be deemed waived unless such claim is asserted by written
notice thereof to the defaulting party within twelve (12) months after the date
on which the non-defaulting party had actual knowledge of the alleged default,
and unless suit be brought thereon within the applicable statute of limitations
time period subsequent to the accrual of such cause of action.

     SECTION 20.30 CRESCENT RIDGE SPACE.

     Tenant is hereby granted an option to enter into a lease with Landlord, or
an affiliate of Landlord, pursuant to which Tenant will lease certain premises
to be constructed by Landlord or its affiliate in a separate project known as
Crescent Ridge in Minnetonka, Minnesota. This option must be exercised, if at
all, on or before March 1, 1999 and will be exercised by Tenant's execution and
delivery of the lease for the Crescent Ridge space to Landlord, said lease to be
on the standard form for Crescent Ridge. The premises demised under that lease
will consist of approximately eight hundred (800) useable square feet to be
located in the lower level of the Crescent Ridge project and will be designated
by Landlord. The term of that lease will be coterminous with the Term of this
Lease; provided that at any time after the second anniversary of that lease, and
following twelve (12) months notice to Landlord, Tenant may terminate that
lease. Tenant will pay gross rent of $12.00 per useable square foot plus the
cost of all utilities delivered to those premises. The Tenant will pay all costs
of constructing required demising walls for those premises and all tenant
improvements in those premises. The premises may be utilized for computer
equipment storage and operation, but for no other use. Tenant will be given the
right, subject to provisions similar to those set forth in Article XXI hereof,
to utilize the roof area of the Crescent Ridge project for one radio antenna.
That lease will contain the same renewal rights as set forth herein. Tenant
acknowledges that the premises demised by such lease will contain no
improvements. The lease for the premises in Crescent Ridge and this Lease will
be cross defaulted. There will be copper and fiber lines to the Point of
Presence in the lower level of Crescent Ridge so as to accomodate T-1 and T-3
communication services.

     SECTION 20.31 TRANSFER BY LANDLORD.

     Landlord may convey its interest in the Demised Premises (and assign its
interest herein) subsequent to the date of Substantial Completion without the
consent of Tenant. Prior to Substantial Completion, Landlord may, without the
Tenant's consent, enter into an agreement so to convey and assign its interest
so long as the date of closing on such agreement is after the date of
Substantial Completion. Prior to Substantial Completion, Landlord may, without
the Tenant's consent, convey its 

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<PAGE>
 
interest in the Demised Premises (and assign its interest herein) to an
"Affiliate" (as hereinafter defined) and in the event of such conveyance, Opus
Northwest, L.L.C. (and not the Affiliate) will (notwithstanding Section 20.6)
retain the obligation to perform all of Landlord's obligations under Article II
hereof.

     For the purpose of the foregoing, "Affiliate" shall mean Opus U.S.
Corporation, Opus U.S., L.L.C. or any subsidiary of the aforementioned entities
or any subsidiary of the Landlord, Gerald Rauenhorst, or any trust, partnership
or limited liability company created by or controlled by Gerald Rauenhorst, or
one or more of his children.


                                   ARTICLE XXI
                                 SATELLITE DISH

     The Landlord hereby grants to Tenant the right to install, maintain and
operate any number of satellite dishes and related equipment and/or antennae
(hereinafter called the "Satellite Dish") on the roof of the Building. Tenant
shall secure all necessary building permits, and all other permits, consents and
approvals of federal, state and local agencies or government authorities
required for the installation, maintenance, operation and removal of the
Satellite Dish, shall provide copies of the same to Landlord, and shall, at all
times during the Term hereof, comply with all requirements of any such agency or
authority, including, but not limited to, height restrictions and screening
requirements, and with the terms, covenants and conditions of any easements,
restrictions, reservations or other encumbrances against the Land. Tenant shall
promptly pay all taxes and license fees imposed by any federal, state or local
governmental agency or authority in connection with the installation, operation
and maintenance of the Satellite Dish. If any zoning approvals or an amendment
to a local zoning ordinance is required, Tenant shall pay any costs and expenses
of Landlord in connection with such approval or amendment. Tenant shall maintain
the Satellite Dish at its own cost and expense in good working order and
condition and free from any hazard to person and property. Tenant shall not
place any load upon the roof of the Building which will exceed the load per
square foot which the roof was designed to carry nor which, in Landlord's
judgment, shall impair the guaranty on the roof membrane. Any damage caused to
the Building or any part thereof which results from the installation, operation,
maintenance, repair, replacement or removal of the Satellite Dish shall be
repaired or replaced promptly by Tenant. Tenant shall not install the Satellite
Dish until Landlord has approved the plans and specifications for the design and
installation (including, without limitation, screening) thereof. Upon the
termination of this Lease or Tenant's right to maintain the Satellite Dish,
Tenant, at its sole cost and expense, shall remove the Satellite Dish and shall
restore the roof of the Building to its condition existing prior to the
installation of the Satellite Dish, ordinary wear and tear accepted. Tenant
shall further repair, at its sole cost and expense, any damage or destruction
caused by the removal of the Satellite Dish.

                                       72
<PAGE>
 
     If Landlord proposes to construct improvements on the property which will
be (after recording of the Bass Creek Business Park 4th Addition) legally
described as Lot 1, Block 1, which will be more than 986.6 feet above sea level,
then the Landlord will provide the Tenant with notice of such proposal and will
afford the Tenant the right to install the Satellite Dish, together with
appropriate cabling, on the roof of the Improvements located on Lot 1, Block 1.
Landlord will, prior to the Commencement Date hereof, execute and record a
restrictive covenant on the title Lot 1, Block 1, Bass Creek Business Park 4th
Addition which restrictive covenant will confirm the foregoing. That restrictive
covenant will provide that it cannot be amended or modified without the consent
of the Landlord, and the Landlord agrees with the Tenant not to modify or amend
that restrictive covenant.


                                  ARTICLE XXII
                            TERMS OF OPTION TO RENEW

     SECTION 22.1 TERMS OF OPTION TO RENEW.

     The Tenant's right to exercise the Renewal Terms referenced in Section 1.2
of this Lease shall not be assignable by Tenant, shall not exerciseable by a
sublessee but shall be upon the following terms and conditions and subject to
the limitations hereinafter set forth:

     (i) That at the time of the "Request for Market Rent" (as defined herein)
and at the time hereinafter set forth for the exercise of each option with
respect to a Renewal Term or the commencement of each Renewal Term, as the case
may be, this Lease shall be in full force and effect and there shall be no
uncured Event of Default hereunder by Tenant.

     (ii) The annual Basic Rent during each Renewal Term shall, notwithstanding
anything herein to the contrary, be equal to ninety-five percent (95%) of the
"Market Rent" (as defined herein) and shall be payable in equal monthly
installments equal to one-twelfth (1/12) of the annual Basic Rent as established
for each Renewal Term, in advance on the first day of each calendar month during
each Renewal Term.

     (iii) Except as otherwise specifically provided in subsection (ii) above,
the Renewal Terms shall be upon the same terms, covenants and conditions
contained in this Lease. All other payments on the part of Tenant to be made as
provided in this Lease shall continue to be paid during each Renewal Term
including, but without limitation, all payments of Additional Rent as required
herein.

     (iv) "Market Rent" means the annual Basic Rent which Landlord would receive
by renting the Demised Premises including all building, structure and fixtures

                                       73
<PAGE>
 
erected thereon, together with all additions, alterations and replacements
thereof in their condition and configuration as of the time of determination of
Market Rent assuming the Landlord to be a prudent person willing to lease but
being under no compulsion to do so, and assuming the Tenant to be a renewal
tenant and prudent person willing to lease but being under no compulsion to do
so, assuming a lease term equal to the term in question, assuming a lease
containing the same terms and provisions as those contained in this Lease, and
giving due regard to all economic factors; including, without limitation, the
size and use of the Demised Premises, a location in the Southwest, Northwest or
West suburbs of Minneapolis, the quality and age of the Building, the extent of
services provided by the Landlord, applicable distinctions between "gross"
leases and "net" leases, the creditworthiness and quality of Tenant, leasing
commissions payable in the market, any inducements, or rental concessions, if
any, and any other relevant term or condition in making such evaluation,
including the benefit to Landlord of having the Demised Premises immediately
rent producing at the date in question..

     (v) Upon determination of the Basic Rent for the Renewal Term, the parties
will execute an Amendment to this Lease confirming the Renewal Term and the
Basic Rent, as determined below.

     SECTION 22.2 EXERCISE OF OPTION TO RENEW.

     If Tenant elects to exercise an option to extend the Term of this Lease, it
shall do so as follows:

     (i) Tenant shall notify Landlord, in writing, of its desire for a
determination of Market Rent, such notice to be given no sooner than five
hundred thirty (530) days and no later than five hundred (500) days prior to the
expiration of the Initial Term or the first Renewal Term (as the case may be),
time being of the essence with respect to such notice (the "Request for Market
Rent").

     During the sixty (60) day period following the receipt of the Request for
Market Rent, Landlord and Tenant will meet on at least two (2) occasions at the
Demised Premises and attempt to agree upon the "Market Rent" for the Demised
Premises for the Renewal Term in question. The Landlord and the Tenant will each
submit their final best offer for Market Rent to the other in writing before the
end of that sixty (60) day period (referred to as the "Landlord's and Tenant's
Final Offer").

     If the parties are unable to agree upon the Market Rent for the Renewal
Term during such sixty (60) day period, Tenant shall, (on or before the date
which is seventy (70) days after delivery of the Request for Market Rent) either
: (i) withdraw its Request for Market Rent; or (ii) deliver an "Appraisal
Request" to Landlord. If Tenant does neither, it will be deemed to have elected
(i) above. If Tenant withdraws, or is deemed to have withdrawn, the Request for
Market Rent, Tenant's option to 

                                       74
<PAGE>
 
renew the Term, and all succeeding options, shall terminate. Tenant shall be
deemed to have made the irrevocable election to exercise the next available
Renewal Term at such time as Tenant delivers an Appraisal Request to Landlord.

     (ii) If Tenant gives Landlord a timely Appraisal Request, each party will,
within twenty (20) days, choose a person with at least five (5) years experience
as a real estate appraiser of income producing assembly and office property in
the market area who shall be a member in good standing of the American Institute
of Real Estate Appraisers (or successor organization or if no such organization
exists then persons of similar professional qualifications), with the
designation M.A.I., and give notice of the name and address of such person to
the other within twenty (20) days of the notice of disagreement from Tenant.
Those two persons shall within five (5) days select a third person who is
experienced in the determination of commercial rental rates for office space in
the market area and the three persons (the "Experts") shall make a determination
of Market Rent as expeditiously as possible thereafter and in any event within
thirty (30) days after the selection of the third Expert. The Landlord's and the
Tenant's Final Offer will be given to the Experts for the purposes of their
review in making their determination. The determination of the Experts shall be
made no later than the date which is 365 days prior to the end of the Term and
shall be made as follows:

     (a)  Each Expert will independently determine the Market Rent and then will
          meet and simultaneously disclose to the other their respective
          determinations.

     (b)  If neither the highest nor the lowest determination differs from the
          middle determination by more than ten percent (10%) of such middle
          determination, then the Market Rent shall be the average of all three
          determinations.

     (c)  If subparagraph (b) does not apply, then the Market Rent shall be the
          average of the two determinations closest by dollar amounts.

     (d)  The Experts shall promptly notify Landlord and Tenant of each of their
          separate determinations and the resulting Market Rent. Except as
          otherwise provided in this Lease, the said appraisal Market Rent
          determination shall be conducted in accordance with the rules then
          obtaining of the American Arbitration Association, and judgment upon
          any appraisal decision rendered may be entered by any Court having
          jurisdiction thereof. The determination of Market Rent pursuant to
          this procedure shall be final, binding and conclusive upon Landlord
          and Tenant.

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<PAGE>
 
     Each party will pay any and all fees and expenses incurred in connection
with such party's Expert and the fees and expenses for the third Expert will be
borne equally by the parties except that if the Market Rent resulting from any
determination under this Article is equal to or greater than ninety-five (95%)
percent of the amount of Market Rent set forth in Landlord's notice to Tenant,
then Tenant shall pay all fees and expenses of all three of the Experts.

     There shall be no further additional right to renew this Lease other than
as herein set forth, and Tenant's failure to timely and effectively make its
Request for Market Rent or to exercise the first Renewal Term shall extinguish
its rights thereto as well as Tenant's right to exercise the second Renewal
Term. Any termination of this Lease shall terminate the right of renewal
contained hereunder.


                                  ARTICLE XXIII
                       TENANT'S OPTION TO EXPAND BUILDING

     SECTION 23.1 TENANT'S OPTION TO EXPAND BUILDING.

     Pursuant to Section 2.1 of this Lease, Landlord has agreed to construct the
Improvements (for purposes of this Article XXIII, the Improvements are sometimes
hereinafter referred to as "Phase One Improvements"). Subject to the terms of
this Article, Landlord hereby further agrees that, at the written request of
Tenant, Landlord will erect upon the Land an expansion to the Phase One
Improvements consisting of an expansion of the Building on the portion of the
Land immediately to the South of the Building (the expansion of the Phase One
Improvements is sometimes hereinafter referred to as the "Phase Two
Improvements". The Phase Two Improvements will consist of no more than 60,000
gross square feet of additional building. The Phase Two Improvements will be
completed in accordance with the provisions of Sections 23.2 through 23.9
hereof, inclusive. Tenant shall make its election to exercise its right to
expand the Building by written notice to Landlord (the "Expansion Notice").
Subject to the provisions hereof regarding a Term Extension, the Expansion
Notice may be given at any time prior to the expiration of the Term.

     Within thirty (30) days of receipt of the Expansion Notice, Landlord and
Tenant will meet a minimum of two (2) times to discuss and to attempt to agree
upon schematic plans and specifications for the Phase Two Improvements (the
"Schematics"). Landlord is not required to approve the Schematics to the extent
that they will, in Landlord's reasonable judgment, impair the structural or
mechanical integrity or diminish the value of the Demised Premises. Within that
same thirty day (30) period, Landlord will furnish Tenant with a site plan
showing the proposed Phase Two Improvements (the "Site Plan"). The Schematics,
the Phase Two Outline Plans and Specifications and the Site Plan will be
prepared at the initial cost of the Tenant.

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<PAGE>
 
     Following written approval of the Schematics by Landlord and Tenant,
Landlord will proceed with the preparation of the "Phase Two Outline Plans and
Specifications" which will be developed from the Schematics. The Phase Two
Outline Plans and Specifications will be submitted to Tenant for its approval
within sixty (60) days of said approval of the Schematics and will contain
similar detail as are contained in the Outline Plans and Specifications attached
hereto as Exhibit "B".

     Within twenty (20) days following receipt of the Phase Two Outline Plans
and Specifications, Tenant will either approve the same or request such changes
as it deems appropriate, which changes will then be incorporated into the Phase
Two Outline Plans and Specifications by Landlord. Landlord and Tenant will agree
upon the Phase Two Outline Plans and Specifications within sixty (60) days of
their approval of the Schematics. Landlord will have no obligation to make
changes to the Phase Two Outline Plans and Specifications which, in Landlord's
judgment, will impair the structural or mechanical integrity of the Building or,
in Landlord's reasonable judgment, diminish the value of the Demised Premises.
During the development of the Phase Two Outline Plans and Specifications,
Landlord will, at Tenant's cost, make application for all required governmental
approvals for the Phase Two Improvements (the "Phase Two Permits") and will
diligently pursue the issuance of those Phase Two Permits. Delay or failure of
issuance of the Phase Two Permits will constitute Excused Delay.

     Upon approval of the Phase Two Outline Plans and Specifications by Landlord
and Tenant, Landlord will advise the Tenant whether, in Landlord's reasonable
judgment, the construction of the Phase Two Improvements can be Substantially
Completed on or before the date which is five (5) full calendar years prior to
the expiration of the Term (as it may have been previously extended), and if not
Landlord will advise the Tenant when the Landlord estimates that the Phase Two
Improvements will be Substantially Complete (the "Landlord's Completion
Estimate"). For the purpose of the Phase Two Improvements, the term "Substantial
Completion" will have the same meaning given it in Section 2.5. After receipt of
the Landlord's Completion Estimate, and as a prerequisite to the Landlord's
obligation to further proceed with the preparation of the Phase Two Final Plans
and Specifications, Tenant must execute and deliver to Landlord an "Expansion
Amendment" (as hereinafter defined). The Expansion Amendment will be executed,
if at all, upon: (i) Tenant's election as to payment for the Phase Two
Improvements, as contemplated in Section 23.4, (ii) determination of the "Phase
One Improvements Basic Rent" for the Term Extension, or the delivery by Tenant
of an "Arbitration Demand" with respect to the Phase One Improvements Basic Rent
for the Term Extension (as both of those terms are defined in Section 23.10).

     The "Expansion Amendment", which will be prepared by Landlord, will provide
as follows:

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<PAGE>
 
     (i) If, pursuant to the Landlord's Completion Estimate, the Phase Two
     Improvements will not be Substantially Complete on or before the date which
     is five (5) full calendar years prior to the expiration of the Term (as the
     same may have previously been extended by reason of the Tenant's exercise
     of Renewal Terms), and if the Tenant elects to pay for the Phase Two
     Improvements pursuant to Section 23.4.1, then the Expansion Amendment, once
     executed by Tenant, will constitute an irrevocable election by Tenant to
     extend the Term of this Lease so that the Term (as it may previously have
     been extended) will expire on a date which is five (5) full calendar years
     after the date of the Substantial Completion of the Phase Two Improvements.
     The period of time by which the Term is extended by reason of the Expansion
     Amendment is called the "Term Extension".

     (ii) The Phase One Improvements Basic Rent for the Term Extension (if a
     Term Extension is required) will be determined in one of two methods and
     will be incorporated into the Expansion Amendment. Those methods are more
     fully described in Section 23.10. If the Phase One Improvements Basic Rent
     has in fact been agreed upon, then the Expansion Amendment will contain
     that agreement. If an Arbitration Demand has been delivered by the Tenant
     with respect to the Phase One Improvements Basic Rent, then the Expansion
     Amendment will identify the date by which the arbitrators are to determine
     the Phase One Improvements Basic Rent. The fact that the Phase One
     Improvements Basic Rent for the Term Extension may not be determined until
     after execution of the Expansion Amendment will not permit the Tenant to
     rescind the Expansion Amendment, it being the intention of the parties that
     the execution of the Expansion Amendment will irrevocably serve to extend
     the Term of this Lease for the Term Extension notwithstanding that the
     Phase One Improvements Basic Rent may not yet be established.

     (iii) As is set forth in 23.3, the Tenant must elect to pay for the Phase
     Two Improvements either through the "Phase Two Basic Rent" or through the
     "Construction Price" (as those terms are defined in Section 23.3). The
     Expansion Amendment will document which election Tenant has chosen and will
     obligate the Tenant to make the payments required by reason of that
     election.

     (iv) If the Tenant pays for the Phase Two Improvements by paying the
     Construction Price, then the Expansion Amendment will contain provisions
     amending Article XIV of this Lease to provide that Tenant shall receive a
     proportion of any condemnation award received on account of a condemnation
     of the Phase Two Improvements, Tenant's proportion to be determined by
     multiplying the Phase Two condemnation award by a percentage derived by
     dividing the unexpired Term as of the date of the taking of the Phase Two

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<PAGE>
 
     Improvements by the unexpired Term as of the date of Substantial Completion
     of the Phase Two Improvements.

     SECTION 23.2 DESIGN OF PHASE TWO IMPROVEMENTS.

     Upon execution of the Expansion Amendment, Landlord will commence the
preparation of the "Phase Two Final Plans and Specifications" so as to be
consistent with the approved Phase Two Outline Plans and Specifications, satisfy
any physical requirements of the site and to comply with all applicable building
and zoning regulations and orders of any duly constituted authority applicable
to construction of said Phase Two Improvements or the use thereof.

     SECTION 23.3 COST OF PHASE TWO IMPROVEMENTS.

     At the time the final Phase Two Outline Plans and Specifications are
approved (which the parties will do following the provisions set forth in
Section 2.1 hereof), Landlord will inform Tenant of the proposed increase in
Basic Rent attributable to the Phase Two Improvements (the "Phase Two Basic
Rent") and Landlord's "Construction Price" (as hereinafter defined) for the
Phase Two Improvements. The "Construction Price" shall include all costs, in the
categories identified on Exhibit B-1, to be incurred in construction the Phase
Two Improvements together with legal costs and other costs of financing of the
Demised Premises, if required, financing the Phase Two Improvements, interim
financing during the construction period and costs for the preparation of the
Site Plan, the schematics, the Phase Two Outline Plans and Specifications and
the Phase Two Final Plans and Specifications.

     If Tenant is dissatisfied with such proposed Phase Two Basic Rent or the
Construction Price, it may solicit bids to include all categories included
within the Construction Price from two or more financially responsible building
contractors experienced in constructing buildings similar to the proposed Phase
Two Improvements and which are reasonably acceptable to Landlord. The
contractors identified on Exhibit "G" (the "Unacceptable Contractor List") will
not be acceptable contractors. Each of such financially responsible building
contractors shall accompany its bid with a bid bond in the amount of its bid,
issued by an acceptable commercial surety licensed to do business in the State
of Minnesota, and shall agree to furnish a completion bond, including a bond
against claims for labor and materials as well as the completion of such Phase
Two Improvements. The competing bids shall include a sum for design and interim
financing and shall provide for no progress payments; but, in place of such
payments, there shall be one payment for the entire work due and payable upon
completion of the work and acceptance by Landlord and Tenant. In determining
whether the Construction Price of Landlord is in excess of the bid of the lowest
financially responsible contractor submitting a bid, the premiums for the
completion bond and mechanic's lien bond shall be eliminated from such
computation.

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<PAGE>
 
     If the Construction Price of Landlord is greater than one hundred three
percent (103%) of the bid of the lowest financially responsible contractor
submitting a bid (with all required bonds), Landlord shall elect OPTION A below.
If the Construction Price of Landlord is equal to or less than one hundred three
percent (103%) of the bid of the lowest financially responsible contractor
submitting a bid (with all required bonds), Landlord shall, within fifteen (15)
days, elect OPTION A or OPTION B below. Option a will be for Landlord to enter
into a construction contract (as Owner) on terms acceptable to Landlord with the
contractor submitting the lower bid providing for the construction of the Phase
Two Improvements by that contractor. Landlord will have no obligation to enter
into that construction contract until Tenant has executed an agreement
reasonably satisfactory to Landlord pursuant to which Tenant is obligated to pay
(and provide security with respect to that obligation) the sums due under that
construction contract. Option b will be for Landlord to lower its Construction
Price to a sum equal to the lowest competing bid. If Landlord elects OPTION B,
then the Construction Price shall be the Construction Price as so adjusted
pursuant to said election.

     If the Construction Price of Landlord is less than the competitive bids,
then Tenant may elect, pursuant to Section 23.4, to have the Phase Two
Improvements constructed by Landlord at Landlord's Construction Price.

     Tenant shall not be given possession of, nor shall Tenant be obligated to
Landlord for the payment of Basic Rent or Additional Rent, with respect to, the
Phase Two Improvements until the Phase Two Improvements are Substantially
Completed (as defined in Section 2.5) herein in accordance with the Phase Two
Final Plans and Specifications. Delay in putting Tenant in possession of said
Phase Two Improvements shall not serve to extend the Term of this Lease or to
make Landlord liable for any direct, indirect, special or consequential damages
arising therefrom.

     SECTION 23.4 PAYMENT FOR PHASE TWO IMPROVEMENTS.

     After final determination of the Phase Two Basic Rent and the Construction
Price as contemplated by Section 23.3, Tenant shall elect one of the following
options:

     23.4.1 To have the Landlord construct the Phase Two Improvements (and pay
     the Phase Two Basic Rent);

     23.4.2 To have the Phase Two Improvements constructed by the lowest bidding
     contractor and pay the Construction Price to Landlord in cash (if Landlord
     elects OPTION A as set forth in Section 23.3);

     23.4.3 To have the Phase Two Improvements constructed by Landlord and pay
     the Construction Price to Landlord in cash (if Landlord elects OPTION B as
     set forth in Section 23.3); or

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<PAGE>
 
     23.4.4 To withdraw the Expansion Notice, in which event the Tenant's right
     to cause the construction of the Phase Two Improvements will be deemed
     terminated and of no further force or effect.

     Tenant shall promptly make such election and (except in the event of
Section 23.4.4) execute the Expansion Amendment, as well as other documentation
contemplated hereby, prior to commencement of construction of the Phase Two
Improvements.

     If Tenant elects 23.4.1 above, then, upon the date that the Phase Two
Improvements are Substantially Completed, the Basic Rent payable under Article
III of this Lease shall be increased by the amount of the Phase Two Basic Rent,
the other sums payable by the Tenant hereunder will be adjusted to reflect the
increase in the Demised Premises attributable to the Phase Two Improvements and
the agreements to be paid, kept, observed and performed by Tenant under this
Lease shall thereupon become applicable to the Phase Two Improvements.

     If Tenant elects 23.4.2 or 23.4.3 above, and provided Tenant furnishes
reasonably adequate security for the payment of such costs, as reasonably
determined by Landlord, and pays all construction costs as the same become
payable, the Basic Rent shall not be adjusted as a result of the construction of
the Phase Two Improvements. If Tenant elects 23.4.2 or 23.4.3, Tenant must pay
the entire Construction Price. If Tenant elects 23.4.2, Tenant must deliver
final lien waivers as required by Landlord with respect to the Phase Two
Improvements. If Tenant elects 23.4.3, Tenant must provide the funds required in
order for Landlord to obtain such final lien waivers.

     It is understood and agreed that notwithstanding payment of all
construction costs for the Phase Two Improvements by Tenant, upon installation,
all Phase Two Improvements, except Tenant's moveable trade fixtures, shall
become the property of Landlord. In the event Tenant elects 23.4.2 or 23.4.3,
Tenant will not be given possession of the Phase Two Improvements until all sums
payable by Tenant are paid. If Tenant elects 23.4.4, then Tenant's option to
expand the Demised Premises shall terminate.

     SECTION 23.5 COMPLETION OF PHASE TWO IMPROVEMENTS.

     Upon execution of the Expansion Amendment and approval of the Phase Two
Final Plans and Specifications, and provided that Tenant has elected Section
23.4.1 or 23.4.3, Landlord shall, subject to Excused Delay, diligently proceed
with the construction of the Phase Two Improvements and complete the same and
deliver possession thereof to Tenant within a reasonable time thereafter.
Landlord will give Tenant written notice of any such Excused Delay specifying
the nature and the period 

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<PAGE>
 
of such Excused Delay within thirty (30) days after the occurrence thereof. The
time of completion of said construction shall be extended for the additional
time caused by such Excused Delay. If Tenant elects Section 23.4.2, then
Landlord will, at Tenant's cost, enforce the construction contract entered into
by Landlord, but Landlord will have no obligation to assure timely Substantial
Completion of the Phase Two Improvements. If the Phase Two Improvements are not
Substantially Complete by the date required by said construction contract, or if
the contractor thereunder materially defaults in its obligations, Landlord may
complete the Phase Two Improvements following thirty (30) days notice to Tenant
and Tenant's failure to either cure said default by the contractor or commence
and diligently prosecute the completion of the Phase Two Improvements. If the
Landlord completes the Phase Two Improvements as set forth in the immediately
preceding sentence, Tenant will pay Landlord, as Additional Rent, all sums
incurred by Landlord in so completing the Phase Two Improvement, together with
interest at the Maximum Rate of Interest.

     SECTION 23.6 TENANT'S RIGHT TO INSPECT.

     During the period of construction of Phase Two Improvements and provided
Landlord is constructing the Phase Two Improvements, Tenant or its designated
agent or agents shall have the right of inspect and Landlord shall cooperate
with Tenant or its designated agent or agents with respect to any such
inspection and facilitate the same as long as such inspection does not interfere
with the work of Landlord in completing the Phase Two Improvements. In the event
Landlord elects to allow another contractor to perform the Phase Two
Improvements, as provided for in Section 23.3 herein, during the period of such
construction (and without limitation of Landlord's other rights set forth in
this Lease), Landlord shall have the right to inspect and Tenant shall cooperate
with Landlord in the inspection of such work.

     SECTION 23.7 COMPLIANCE WITH PLANS AND SPECIFICATIONS.

     At least five (5) days prior to Substantial Completion of the Phase Two
Improvements by Tenant, and provided that Landlord constructed the Phase Two
Improvements, Landlord and Tenant will agree upon a list of all punch list items
not completed in accordance with the Phase Two Final Plans and Specifications
and Landlord shall forthwith complete said punch list items. The acceptance of
possession of the Phase Two Improvements by Tenant shall be deemed conclusively
to establish that the Phase Two Improvements have been Substantially Completed,
subject to any punchlist items; provided, however, that Tenant may supplement
the punch list by identifying punch list items which Tenant establishes were
deficiencies in the Phase Two Improvements as of the date of Substantial
Completion, so long as such supplemental punch list items are identified for
Landlord within one hundred twenty (120) days following Substantial Completion.
Provided that Landlord constructed the Phase Two Improvements Landlord will
complete said supplemental punch list items within sixty (60) days, or such
longer period as may be reasonably required.

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<PAGE>
 
     If Landlord did not construct the Phase Two Improvements, the failure to
complete the Phase Two Improvements will not excuse the Tenant's obligation to
pay for them, pursuant to the terms hereof.

     SECTION 23.8 GUARANTY OF IMPROVEMENTS.

     Provided that Landlord constructs the Phase Two Improvements, Landlord
guarantees the Phase Two Improvements and such other items as are covered by the
final plans and specifications against defective workmanship and/or defective
materials for a period of one year from the date of Substantial Completion of
the Phase Two Improvements. Provided that Landlord constructs the Phase Two
Improvements, Landlord does further agree, at its sole cost and expense to
repair or replace a defective item occasioned by defective workmanship and/or
defective materials during said one year period. Performance of such one (1)
year guaranty shall be Landlord's sole obligation with respect to defective
workmanship or materials, and Tenant's rights to enforce such one (1) year
guaranty shall be Tenant's sole and exclusive remedy with respect to such
defective workmanship and materials in limitation of any contract, warranty or
other rights, whether express or implied, that Tenant may have under applicable
laws.

     From and after the expiration of the one-year guaranty of Landlord against
defective workmanship and materials, and provided that Landlord constructs the
Phase Two Improvements, Landlord agrees to cooperate with Tenant in the
enforcement by Tenant, at Tenant's sole cost and expense, of any excess
warranties or guaranties of workmanship or materials given by subcontractors or
materialmen that guarantee or warrant against defective workmanship or materials
for a period of time in excess of the one-year period described above and to
cooperate with Tenant in the enforcement by Tenant, at Tenant's sole cost and
expense, of any service contracts that provide service, repair or maintenance to
any of the Phase Two Improvements constructed by Landlord for a period of time
in excess of such one-year period. Upon expiration of the one year guaranty of
Landlord, Landlord will assign to Tenant any then unexpired warranties which
Landlord received from any subcontractors performing work with respect to the
Phase Two Improvements.

     SECTION 23.9 ACCEPTANCE OF PHASE TWO IMPROVEMENTS.

     Save and except for the aforesaid one year guaranty against defective
materials and/or defective workmanship and related obligations referred to in
Section 23.8 above (to the extent applicable), and save and except for the
incomplete items referred to in Section 23.7 above (to the extent applicable),
Tenant, upon occupying the Phase Two Improvements, shall thereafter have and
hold said Phase Two Improvement as the same shall then be without any liability
or obligation on the part of Landlord for making any alterations, improvements
or repairs of any kind in or about the Phase Two 

                                       83
<PAGE>
 
Improvements for the entire Term of this Lease, including any renewal or
extensions thereof and Tenant agrees to maintain the Demised Premises, including
the Phase Two Improvements and all parts thereof, in good and sufficient state
of repair in accordance with the provisions of this Lease.

     SECTION 23.10 BASIC RENT FOR PHASE ONE IMPROVEMENTS DURING TERM EXTENSION.

     If a Term Extension is required, it will be necessary for the parties to
agree upon the "Phase One Improvements Basic Rent" for the Term Extension. The
Phase One Improvements Basic Rent will be determined as follows.

     Upon Tenant's receipt of the Landlord's Completion Estimate, and during the
thirty (30) day period following that receipt, the parties will meet on at least
two (2) occasions at the Demised Premises in order to attempt to agree upon the
Phase One Improvements Basic Rent for the Term Extension. If the parties are
successful in reaching that agreement, the Phase One Improvements Basic Rent as
so agreed will be incorporated into the Expansion Amendment and Tenant will pay
that Phase One Improvements Basic Rent during the Term Extension. If the parties
are unable to agree upon the Phase One Improvements Basic Rent, then the
Landlord's final best offer for the Phase One Improvements Basic Rent will be
documented and the Tenant's final best offer for Phase One Improvements Basic
Rent will be documented and those offers will be called the "Landlord's and
Tenants Final Offer".

     If the parties are unable to reach agreement on the Phase One Improvements
Basic Rent within said thirty days, then Tenant will (within an additional ten
(10) days) either withdraw its Expansion Notice, in which event there will be no
Phase Two Improvements constructed, or will deliver an "Arbitration Demand." If
Tenant gives Landlord a timely Arbitration Demand, then the parties will follow
the procedures set forth in Section 22.2 (ii) except that the Experts will be
directed to determine the Market Rent for the Phase One Improvements for the
Term Extension. In making that determination, the Experts will be directed to
ignore the fact that the Phase Two Improvements will be constructed.

     The Basic Rent for the Phase One Improvements for the Term Extension will
be 100% of the Market Rent for the Phase One Improvements as so determined by
the Experts and such determination shall be final, binding and conclusive upon
Landlord and Tenant and shall be incorporated into a supplemental Expansion
Amendment.

                                  ARTICLE XXIV
                               FIT PLAN ALLOWANCE

     Landlord has paid to Setter, Leach & Lindstrom the sum of Fourteen Thousand
Six Hundred Sixty One and 00/100 Dollars ($14,661.00) for obligations incurred
by 

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Tenant in connection with the completion of a preliminary fit plan of the
Demised Premises, which plan was prepared by Setter, Leach & Lindstrom.

                                   ARTICLE XXV
                              NET RENT PROHIBITION

     The provisions of this Lease to the contrary notwithstanding, if and so
long as Teachers Insurance and Annuity Association of America ("Teachers") shall
be the holder of a mortgage or deed of trust placed upon the Demised Premises or
the Land, the following provisions shall apply:

     (a) Basic Rent and Additional Rent will not be based in whole or in part on
the income or profits derived from the Demised Premises except for percentage
rent (if any) based on gross (not net) receipts or sales of the Lessee;

     (b) If Teachers, as the holder of a mortgage or deed of trust upon the
Demised Premises or the Land, succeeds to the Landlord's interest under the
Lease and is advised by its counsel that all or any portion of the Basic Rent or
Additional Rent payable under the Lease is or may be deemed to be unrelated
business income within the meaning of the Internal Revenue Code of 1986 or
regulations issued thereunder, Teachers may elect to amend unilaterally the
calculation of Basic Rent or Additional Rent so that none of the Basic Rent or
Additional Rent payable to Teachers under the Lease will constitute unrelated
business income, provided, however such amendment will not increase Tenant's
payment obligations or other liability under the Lease or reduce the Landlord's
obligations under the Lease; and

     (c) If the provisions of subsection (b) above apply, and if Teachers
requests, the Tenant agrees to execute any document Teachers request which is
reasonably necessary to effect such amendment of the Lease.

     Tenant acknowledges the foregoing and agrees to incorporate the foregoing
provisions in any sublease of all or any portion of the Demised Premises so that
such provisions apply in the same manner to any sublease of all or any portion
of the Demised Premises as they apply to the Lease of the Demised Premises.

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<PAGE>
 
                  IN WITNESS WHEREOF, each of the parties hereto has caused this
Lease to be duly executed as of the day and year first above written.


                                  LANDLORD:

                                  OPUS NORTHWEST, L.L.C.
                                  a Delaware limited liability company



                                  By /s/  James B. Heller
                                     ------------------------------- 

                                  Its  V.P. Gen Mgr.
                                     -------------------------------

                                  TENANT:

                                  COMPUTER NETWORK
                                  TECHNOLOGY CORPORATION,
                                  a Minnesota corporation


                                  By /s/  Thomas G. Hudson
                                     -------------------------------

                                  Its  CEO
                                     -------------------------------

                                       86