Exhibit 10.48

SUPPLEMENT TO GUARANTEE AGREEMENT

Supplement No.l, dated as of May 30, 2006, to the Guarantee Agreement, dated as
of August 25, 2003, among Monitronics International, Inc., a Texas corporation
(the “Borrower”), and Bank of America, N.A., successor to Fleet National Bank,
as administrative agent under the Credit Agreement referred to in the next
paragraph (as amended, restated, supplemented or otherwise modified from time to
time, the “Guarantee Agreement”).

A.            Reference is made to the Credit Agreement, dated as of August 25,
2003, as amended by the First Amendment to Credit Agreement dated July 14, 2004,
the Second Amendment to Credit Agreement dated March 28, 2005 and Third
Amendment to Credit Agreement dated March 29, 2006, among the Borrower, the
Lenders from time to time party thereto, and Bank of America, N.A., as
Administrative Agent and Syndication Agent (as so amended and as further
amended, restated, supplemented or otherwise modified from time to time, the
“Credit Agreement”). Capitalized terms used herein and not defined herein shall
have the meanings assigned to such terms in the Credit Agreement and the
Guarantee Agreement.

B.            Section 20 of the Guarantee Agreement provides that additional
Subsidiaries of the Borrower may become Guarantors under the Guarantee Agreement
by execution and delivery of an instrument in the form of this Supplement. The
undersigned Subsidiary (the “New Guarantor”) is executing this Supplement in
accordance with the requirements of the Credit Agreement to become a Guarantor
under the Guarantee Agreement in order to induce the Lenders to make additional
Loans and as consideration for Loans previously made.

Accordingly, the Administrative Agent and the New Guarantor agree as follows:

Section 1.              In accordance with Section 20 of the Guarantee
Agreement, the New Guarantor by its signature below becomes a Guarantor under
the Guarantee Agreement with the same force and effect as if originally named
therein as a Guarantor, and the New Guarantor hereby (a) agrees to all the terms
and provisions of the Guarantee Agreement applicable to it as a Guarantor
thereunder and (b) represents and warrants that the representations and
warranties made by it as a Guarantor thereunder are true and correct on and as
of the date hereof, including, without limitation, with respect to itself, its
operations and its assets and properties. Each reference to a “Guarantor” in the
Guarantee Agreement shall be deemed to include the New Guarantor. The Guarantee
Agreement is hereby incorporated herein by reference.

Section 2.              The New Guarantor represents and warrants to the
Administrative Agent and the other Credit Parties that it has all requisite
organizational and other powers and authority to execute, deliver and perform
its obligations under this Supplement and this Supplement has been duly
authorized, executed and delivered by it and constitutes its legal, valid and
binding obligation, enforceable against it in accordance with its terms.

Section 3.              This Supplement may be executed in counterparts, each of
which shall constitute an original, but all of which, when taken together, shall
constitute but one contract.

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This Supplement shall become effective when the Administrative Agent shall have
received counterparts of this Supplement that, when taken together, bear the
signatures of the New Guarantor and the Administrative Agent. Delivery of an
executed counterpart of this Supplement by facsimile transmission shall be as
effective as delivery of a manually executed counterpart of this Supplement.

Section 4.              Except as expressly supplemented hereby, the Guarantee
Agreement shall remain unchanged in full force and effect.

Section 5.              THIS SUPPLEMENT SHALL BE GOVERNED BY, AND CONSTRUED IN
ACCORDANCE WITH, THE INTERNAL LAWS (AS OPPOSED TO THE CONFLICTS OF LAW
PROVISIONS, BUT INCLUDING SECTIONS 5-1401 AND 5-1402 OF THE GENERAL OBLIGATIONS
LAW OF THE STATE OF NEW YORK) AND DECISIONS OF THE STATE OF NEW YORK.

Section 6.              In case any one or more of the provisions contained in
this Supplement should be held invalid, illegal or unenforceable in any respect,
the validity, legality and enforceability of the remaining provisions contained
herein and in the Guarantee Agreement shall not in any way be affected or
impaired thereby (it being understood that the invalidity of a particular
provision hereof in a particular jurisdiction shall not in and of itself affect
the validity of such provision in any other jurisdiction). The parties hereto
shall endeavor in good-faith negotiations to replace the invalid, illegal or
unenforceable provisions with valid provisions the economic effect of which
comes as close as possible to that of the invalid, illegal or unenforceable
provisions.

Section 7.              All communications and notices hereunder shall be in
writing and given as provided in Section 14 of the Guarantee Agreement. All
communications and notices hereunder to the New Guarantor shall be given to it
at the address set forth under its signature below.

Section 8.              The New Guarantor agrees to reimburse the Administrative
Agent for its reasonable out-of-pocket expenses in connection with this
Supplement, including the reasonable fees, disbursements and other charges of
counsel for the Administrative Agent.

[Signature page follows]

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IN WITNESS WHEREOF, the New Guarantor and the Administrative Agent have duly
executed this Supplement to the Guarantee Agreement as of the day and year first
above written.

MONITRONICS CANADA, INC.

 

 

 

 

 

By:

/s/ Stephen M. Hedrick

 

 

Name:

STEPHEN M. HEDRICK

 

 

Title:

VICE PRESIDENT-FINANCE

 

 

 

BANK OF AMERICA, N.A,

as Administrative Agent

 

 

By:

/s/ John Lynch

 

Name:

John Lynch

 

Title:

Senior Vice President

 

 

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