<PAGE>   1



                                    FORM 10-Q
                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

/X/ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE
    ACT OF 1934
                For the quarterly period ended September 30, 1999


                                       OR
          / / TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE


                         SECURITIES EXCHANGE ACT OF 1934
                   For the transition period from      to     .



                        Commission file number 333-51857

--------------------------------------------------------------------------------


                                 PLAINWELL INC.
             (Exact name of registrant as specified in its charter)

                      Delaware                  38-3391489
           (State or other jurisdiction of   (I.R.S. Employer
            incorporation or organization)   Identification No.)

                 200 Allegan Street
                Plainwell, Michigan                       49080
       (Address of principal executive offices)       (Zip Code)


        Registrant's telephone number, including area code: 616-685-2500

                                 Not Applicable
              (Former name, former address, and former fiscal year,
                         if changed since last report)


--------------------------------------------------------------------------------

Indicate by check mark whether the Registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months (or for such shorter period that the Registrant was
required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days. Yes / X/ No / /.

Indicate the number of shares outstanding of each of the issuer's classes of
common stock as of October 29, 1999: 500 shares, $1 par value Common Stock
outstanding.


<PAGE>   2


                                 PLAINWELL INC.
                                    FORM 10-Q


                                      INDEX

                                                                            PAGE
--------------------------------------------------------------------------------


PART I.           FINANCIAL INFORMATION

Item 1.  Financial Statements (Unaudited)

         Condensed Statements of Operations for the three and nine months
             ended September 30, 1999 and 1998                               3

         Condensed Balance Sheets at September 30, 1999 and December 31,
             1998                                                            4

         Condensed Statements of Cash Flows for the nine months ended
             September 30, 1999 and 1998                                     5

         Notes to Condensed Financial Statements - September 30, 1999        6


Item 2.  Management's Discussion and Analysis of Financial Position
             and Results of Operations                                      11

Item 3.  Quantitative and Qualitative Disclosures About Market Risk         16


PART II.          OTHER INFORMATION

Item 1.  Legal Proceedings                                                  17

Item 4.  Submission of Matters to a Vote of Security Holders                17

Item 6.  Exhibits and Reports on Form 8-K                                   17

Signatures                                                                  18

Exhibit Index                                                               19






                                       2





<PAGE>   3



PART I
                                 PLAINWELL INC.
                       CONDENSED STATEMENTS OF OPERATIONS
                             (Thousands of Dollars)
                                   (Unaudited)

<TABLE>
<CAPTION>
                                     Three months ended            Nine months ended
                                         September 30,                September 30,
                                   ------------------------      ------------------------
                                     1999           1998            1999          1998
                                   ---------      ---------      ---------      ---------
<S>                                <C>            <C>            <C>            <C>
Net sales                          $  52,802      $  55,797      $ 159,026      $ 140,924
Cost of sales                         46,896         48,552        140,248        122,605
                                   ---------      ---------      ---------      ---------
    Gross profit                       5,906          7,245         18,778         18,319

Selling, general and
    administrative expenses            4,942          4,654         14,005         11,717
                                   ---------      ---------      ---------      ---------

Operating income                         964          2,591          4,773          6,602

Interest expense                       4,526          4,147         13,152         10,064
                                   ---------      ---------      ---------      ---------

Loss before taxes
    and extraordinary item            (3,562)        (1,556)        (8,379)        (3,462)
Income tax benefit                    (1,073)          (279)        (2,329)          (818)
                                   ---------      ---------      ---------      ---------

Loss before extraordinary item        (2,489)        (1,277)        (6,050)        (2,644)
Extraordinary item, net of tax            --             --             --           (597)
                                   ---------      ---------      ---------      ---------

Net loss                           $  (2,489)     $  (1,277)     $  (6,050)     $  (3,241)
                                   =========      =========      =========      =========
</TABLE>




           See accompanying notes to condensed financial statements.

                                       3
<PAGE>   4


                                 PLAINWELL INC.
                            CONDENSED BALANCE SHEETS
                  (Thousands of Dollars, Except Share Amounts)

<TABLE>
<CAPTION>
                                                    September 30, 1999          December 31, 1998
                                                    ------------------          -----------------
                                                        (Unaudited)
<S>                                                 <C>                         <C>
ASSETS

Current assets:
      Cash and cash equivalents                     $            1,334          $           1,846
      Accounts receivable, net                                  24,449                     19,387
      Inventories                                               28,744                     27,750
      Other                                                      8,471                      5,599
                                                    ------------------          -----------------
              Total current asset                               62,998                     54,582

Property, plant and equipment                                  153,187                    148,630
Accumulated depreciation                                       (19,644)                   (11,220)
                                                    ------------------          -----------------
      Net property, plant and equipment                        133,543                    137,410
Other Assets                                                    33,111                     33,240
                                                    ------------------          -----------------

              Total assets                          $          229,652          $         225,232
                                                    ==================          =================

LIABILITIES AND STOCKHOLDER'S EQUITY

Current liabilities:
      Accounts payable                              $           17,209          $          14,642
      Accrued liabilities                                       12,618                     18,093
      Notes payable                                                150                        150
                                                    ------------------          -----------------
              Total current liabilities                         29,977                     32,885

Long-term debt                                                 169,864                    152,915
Other long-term liabilities                                     16,380                     15,951
                                                    ------------------          -----------------

              Total liabilities                                216,221                    201,751

Commitments and Contingencies (Notes 4 and 5)

Stockholder's equity:
      Common stock $1 par value, authorized 1,000
              shares, issued and outstanding 500
                shares                                               1                          1
      Paid-in capital                                           28,319                     28,319
      Accumulated deficit                                      (14,889)                    (4,839)
                                                    ------------------          -----------------
              Total stockholder's equity                        13,431                     23,481
                                                    ------------------          -----------------
              Total liabilities and stockholder's
                equity                              $          229,652          $         225,232
                                                    ==================          =================
</TABLE>


           See accompanying notes to condensed financial statements.

                                       4
<PAGE>   5


                                 PLAINWELL INC.
                       CONDENSED STATEMENTS OF CASH FLOWS
                             (Thousands of Dollars)
                                   (Unaudited)


<TABLE>
<CAPTION>
                                                           Nine months ended
                                                              September 30,
                                                         ------------------------
                                                           1999           1998
                                                         ---------      ---------
<S>                                                      <C>            <C>
OPERATING ACTIVITIES:
Net loss                                                 $  (6,050)     $  (3,241)
Adjustments to reconcile net loss to net
      cash used in operating activities:
    Depreciation and amortization                           10,446          8,059
    Deferred income taxes                                   (2,329)        (1,209)
    Changes in operating assets and liabilities             (9,847)        (3,070)
                                                         ---------      ---------
  Net cash provided by (used in) operating
        activities                                          (7,780)           539

INVESTING ACTIVITIES:
Capital expenditures                                        (5,681)        (2,888)
Purchase of Consumer Products Division                          --       (122,317)
                                                         ---------      ---------
  Net cash used in investing activities                     (5,681)      (125,205)

FINANCING ACTIVITIES:
Net borrowings (payments) under
    Revolving lines of credit                               16,949         (4,095)
Repayment of term loan                                          --        (13,500)
Issuance of long-term debt                                      --        130,000
Deferred financing costs                                        --         (7,206)
Capital contribution                                            --         24,634
Dividends paid                                              (4,000)        (4,288)
                                                         ---------      ---------

  Net cash provided by financing
        activities                                          12,949        125,545
                                                         ---------      ---------

Net increase (decrease) in cash and cash equivalents          (512)           879


Cash and cash equivalents at beginning of period             1,846            772
                                                         ---------      ---------
Cash and cash equivalents at end of period               $   1,334      $   1,651
                                                         =========      =========
</TABLE>



           See accompanying notes to condensed financial statements.

                                       5
<PAGE>   6


                                 PLAINWELL INC.
               NOTES TO CONDENSED FINANCIAL STATEMENTS (UNAUDITED)
                               SEPTEMBER 30, 1999



NOTE 1.  BASIS OF PRESENTATION


PLAINWELL INC. (the "Company") is a leading U.S. producer and marketer of value
added paper products for niche markets within the paper industry. The Company
conducts its business through two divisions: the Consumer Products Division,
which produces private label consumer tissue products such as bath tissue, paper
towels, napkins and facial tissue and the Specialty Paper Division, which
produces premium coated and uncoated printing papers and release and other
technical/specialty papers.

The Company is a wholly owned subsidiary of Plainwell Holding Company
("Holdings"). Holdings and two affiliated entities, Shasta Holdings Company and
Shasta Paper Company are wholly owned subsidiaries of Plainwell Shasta Holdings
Inc. Effective March 6, 1998, Plainwell Paper Company merged with and into the
Company and its business operates as the Specialty Paper Division of the
Company. Also effective March 6, 1998, the Company purchased substantially all
of the assets, properties and rights and assumed certain related liabilities of
the tissue business of Pope & Talbot, Inc., which operates as the Consumer
Products Division of the Company (see Note 2).

The historical information of the Company for the nine months ended September
30, 1998 includes the results of the Consumer Products Division beginning with
the acquisition date (March 6, 1998).

The balance sheet at December 31, 1998 has been derived from the audited
financial statements at that date but does not include all the information and
footnotes required by generally accepted accounting principles for complete
financial statements.

The accompanying unaudited condensed financial statements have been prepared in
accordance with generally accepted accounting principles for interim financial
information and the instructions to Form 10-Q and Article 10 of Regulation S-X.
Accordingly, they do not include all the information and notes required by
generally accepted accounting principles for complete financial statements. In
the opinion of management, all adjustments (consisting only of adjustments of a
normal and recurring nature) considered necessary for a fair presentation of the
financial position and results of operations have been included. Operating
results for the three and nine months ended September 30, 1999 are not
necessarily indicative of the results that might be expected for the year ending
December 31, 1999. For further information, refer to the financial statements
and footnotes for the year ended December 31, 1998 included in the Company's
Report on Form 10-K, filed March 31, 1999.

NOTE 2.  ACQUISITIONS

Effective March 6, 1998, the Company purchased substantially all of the assets,
properties and rights and assumed certain related liabilities of the tissue
business of Pope & Talbot, Inc. The total purchase price, including the costs of
the acquisition, was $122,317,000.

                                       6

<PAGE>   7


                                 PLAINWELL INC.
               NOTES TO CONDENSED FINANCIAL STATEMENTS (UNAUDITED)


The following unaudited pro forma results of operations for the nine months
ended September 30, 1998 assumes the acquisition, merger and related
transactions occurred as of January 1, 1998 (in thousands of dollars):

<TABLE>
<CAPTION>
                                                           Nine Months Ended
                                                          September 30, 1998
                                                        ------------------------
<S>                                                      <C>
          Net sales                                             $163,893
          Loss before extraordinary item                          (3,529)
</TABLE>

This pro forma information does not purport to be indicative of the results that
actually would have been obtained if the combined operations had been conducted
during the periods presented and is not intended to be a projection of future
results.


NOTE 3.  INVENTORIES

Inventories consist of the following (in thousands of dollars):

<TABLE>
<CAPTION>
                                                             September 30, 1999          December 31, 1998
                                                           ------------------------   ------------------------

<S>                                                            <C>                        <C>
          Finished goods                                           $18,291                    $17,173
          Work-in-process                                            4,756                      4,444
          Materials and supplies                                     5,697                      6,133
                                                                   -------                    -------
              Total                                                $28,744                    $27,750
                                                                   =======                    =======
</TABLE>

NOTE 4.  COMMITMENTS AND CONTINGENCIES

The Company is involved in various legal proceedings in the ordinary course of
business. Although the final outcome of any legal proceeding or environmental
matter is subject to a great many variables and cannot be predicted with any
degree of certainty, the Company presently believes that the ultimate outcome
from these proceedings would not have a material adverse effect on the current
financial position or on the operations of the Company; however, in any given
future reporting period such proceedings or matters could have a material effect
on the results of operations.

NOTE 5.  ENVIRONMENTAL REMEDIATION

The Company is committed to abiding by the Environmental, Health and Safety
Principles of the American Forest & Paper Association. Each capital project has
been planned to comply with applicable environmental regulations and to enhance
environmental protection at existing facilities. The Company faces increasing
capital expenditures and operating costs to comply with expanding and more
stringent environmental regulations, although compliance with existing
environmental regulations is not expected to have a materially adverse effect on
the Company's earnings, financial position, or competitive position.


                                       7

<PAGE>   8


                                 PLAINWELL INC.
               NOTES TO CONDENSED FINANCIAL STATEMENTS (UNAUDITED)


The Comprehensive Environmental Response, Compensation and Liability Act
(CERCLA) and similar state "Superfund" laws impose liability, without regard to
fault or to the legality of the original action, on certain classes of persons
(referred to as potentially responsible parties or PRPs) associated with a
release or threat of a release of hazardous substances into the environment.
Financial responsibility for the cleanup or other remediation of contaminated
property or for natural resource damages can extend to previously owned or used
properties, waterways, and properties owned by third parties, as well as to
properties currently owned and used by a company even if contamination is
attributable entirely to prior owners. The Company has been identified by
certain governmental entities or other parties as a potentially responsible
party with respect to possible investigation and cleanup costs associated with
certain contaminated sites. The Company has recorded a liability for the
estimated work at the locations and a receivable for remediation costs
recoverable under related indemnification agreements.

The Company owns and operates a landfill in Washington Township, Wisconsin, for
disposal of its papermaking sludge. The Company has closed two of the three
sections of the landfill and is currently monitoring those sections in
accordance with requirements of state environmental laws. The Company expects to
begin closure of the third section by 2002. Estimated closure costs of $1.3
million are being accrued over the operating life of the landfill. Monitoring
costs are estimated at $80,000 per year and will be required for 40 years
following the closure of the landfill. The Company is also considered a PRP with
respect to the Blue Valley Landfill Superfund Site in Eau Claire, Wisconsin.
Based on the amount of material sent to the Blue Valley Landfill and the
Company's indemnification with a predecessor company, the Company does not
anticipate that its costs associated with the site will have a material adverse
effect on its operations, liquidity or financial condition.

In 1998, the EPA published regulations establishing standards and limitations
for non-combustion sources under the Clean Air Act and revised regulations under
the Clean Water Act. The new rules require more stringent controls on air
emissions and wastewater discharges from the Company's paper and tissue mills.
These regulations are collectively referred to as the "Cluster Rules." The
Company estimates that future capital spending to comply with the Cluster Rules
could be up to $5.0 million.


NOTE 6.  PAID-IN CAPITAL AND STOCKHOLDER'S EQUITY

In January 1999, Shasta Paper Company acquired the pulp and paper operations of
Simpson Paper Company located in Anderson, California. The Company paid a
dividend of $4.0 million to finance the transaction. The Company has various
transactions with Shasta Paper Company, including intercompany sales, shared
sales and marketing costs, shared corporate administrative costs, and shared
information services costs.


                                       8
<PAGE>   9


                                 PLAINWELL INC.
               NOTES TO CONDENSED FINANCIAL STATEMENTS (UNAUDITED)

NOTE 7.  BUSINESS SEGMENT INFORMATION

Financial information by business segment follows (in thousands of dollars):

<TABLE>
<CAPTION>
                                              Consumer     Specialty
                                              Products       Paper
                                              Division      Division    Corporate       Total
                                             -----------   ----------   ----------    ---------
<S>                                           <C>          <C>          <C>           <C>
Three months ended September 30, 1999:
    Net sales                                 $ 31,816     $ 20,986     $      -      $ 52,802
    Income (loss) before interest, income
        taxes and extraordinary item               464          948         (448)          964
    Interest expense                               314           37        4,175         4,526
    Depreciation and amortization                3,042          369           --         3,411
    Capital expenditures                         2,021          237          281         2,539
    Total assets                               159,314       55,575       14,763       229,652

Three months ended September 30, 1998:
    Net sales                                 $ 36,100     $ 19,697     $      -      $ 55,797
    Income (loss) before interest, income
        taxes and extraordinary item             2,934          156         (499)        2,591
    Interest expense                               203           67        3,877         4,147
    Depreciation and amortization                2,920          368            -         3,288
    Capital expenditures                         1,392          398            -         1,790
    Total assets                               163,485       51,004        9,840       224,329

Nine months ended September 30, 1999:
    Net sales                                 $ 98,349     $ 60,677     $      -      $159,026
    Income (loss) before interest, income
        taxes and extraordinary item             3,087        2,808       (1,122)        4,773
    Interest expense                               748          110       12,294        13,152
    Depreciation and amortization                8,754        1,107            -         9,861
    Capital expenditures                         4,382          537          762         5,681

Nine months ended September 30, 1998:
    Net sales                                 $ 81,691     $ 59,233     $      -      $140,924
    Income (loss) before interest, income
        taxes and extraordinary item             6,523        1,119       (1,040)        6,602
    Interest expense                               476          146        9,442        10,064
    Depreciation and amortization                6,503        1,104            -         7,607
    Capital expenditures                         2,136          752            -         2,888
</TABLE>


                                       9
<PAGE>   10


                                 PLAINWELL INC.
               NOTES TO CONDENSED FINANCIAL STATEMENTS (UNAUDITED)

NOTE 8.  SUBSEQUENT EVENT

In November 1999, the Company replaced its senior credit facility with Fleet
Business Credit Corporation (formerly Sanwa Business Credit Corporation) (the
"Fleet Facility") with a new senior facility between PLAINWELL INC. and Congress
Financial Corporation (the "Congress Facility"). The Congress Facility has a
three year term and provides for a maximum credit capacity of $55.0 million. The
availability under the Congress Facility is based on the sum of (1) 85% of
eligible accounts receivable (as defined within the agreement) plus, (2) the
lesser of 60% of eligible inventory (as defined within the agreement), and $25
million, plus (3) $25 million (such amount will be reduced ratably over a 60
month period). The $55.0 million Congress Facility may also be utilized for
letter of credit guaranties not to exceed $30 million outstanding at anytime.
Interest on the Congress Facility is payable monthly at either (i) the Prime
Rate plus one half percent per annum or (ii) two and one half percent per annum
in excess of the adjusted Eurodollar rate. The Company used the proceeds of the
Congress Facility to repay the outstanding revolver balances and accrued
interest due under the Fleet Facility and to fund a $0.7 million penalty in
connection with the early termination of the Fleet Facility. The Company also
utilized $20 million under the Congress Facility to back-up its current letter
of credit guaranty related to its Eau Claire Industrial Revenue Bonds. During
the fourth quarter of 1999, the Company will record as an extraordinary charge,
net of taxes, the $0.7 million early termination penalty and $0.6 million of
unamortized deferred debt costs related to the Fleet Facility.




                                       10

<PAGE>   11


ITEM 2. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
OF OPERATIONS


RESULTS OF OPERATIONS

The Company acquired the Consumer Products Division on March 6, 1998. The
historical financial information of the Company for the nine months ended
September 30, 1998 includes the results of the Consumer Products Division since
the date of acquisition March 6, 1998.

THREE MONTHS ENDED SEPTEMBER 30, 1999 COMPARED TO THE THREE MONTHS ENDED
SEPTEMBER 30, 1998

NET SALES

The Company's net sales decreased slightly to $52.8 million for the three months
ended September 30, 1999 compared to $55.8 million for the three months ended
September 30, 1998. This decline reflects a $4.3 million reduction in net sales
at the Consumer Products Division partially offset by a $1.3 million increase in
net sales at the Specialty Paper Division.

The decrease in net sales at the Consumer Products Division reflects an 11.0%
reduction in sales volume and a 2.0% decline in the average net selling price
per unit compared to the third quarter of 1998. The reduction in sales volume is
primarily due to management's decision during the third quarter of 1999 to
discontinue certain incremental business not currently considered profitable.
Although the Consumer Products Division produces much of the paper used in its
conversion operations, the division has historically purchased additional paper
from third parties to take advantage of available converting capacity. Rising
pulp and paper prices coupled with downward market pressure on selling prices,
made this incremental converting business unattractive.

The $1.3 million increase in net sales at the Specialty Paper Division reflects
an 11.1% increase in sales volume partially offset by a 4.2% decrease in the
average net selling price per unit sold. The Specialty Paper Division has
continued to capitalize on sales and marketing synergies created through its
affiliation with Shasta Paper Company to increase sales volume. The decrease in
average sales price primarily reflects changes in the division's sales mix.

COST OF SALES AND GROSS PROFIT

Cost of sales decreased slightly to $46.9 million for the three months ended
September 30, 1999 compared with $48.6 million during the same period of 1998
primarily due to various cost savings initiatives put in place during 1999 and
lower overall production volume. Increasing fiber prices during the end of the
second quarter and continuing through the third quarter of 1999, coupled with
the reduction in average net selling prices discussed above, resulted in a
decrease in the Company's gross profit percentage to approximately 11.2%
compared to 13.0% during the third quarter of 1998.

SELLING, GENERAL AND ADMINISTRATIVE EXPENSES

Selling, general and administrative expenses remained relatively flat at $4.9
million for the three months ended September 30, 1999 compared to $4.7 million
for the quarter ended September 30, 1998.


                                       11

<PAGE>   12


ITEM 2. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
OF OPERATIONS, CONTINUED


INCOME TAXES

The Company has recorded federal tax benefits related to the Company's
consolidated net loss before taxes during the third quarter of 1999 and 1998.
The federal tax benefit is partially offset by applicable state tax provisions.
Due to the increase in the Company's net loss before taxes, the effective net
tax benefit rose to 30.1% in the third quarter of 1999 compared to 17.9% in the
third quarter of 1998.

NINE MONTHS ENDED SEPTEMBER 30, 1999 COMPARED TO THE NINE MONTHS ENDED SEPTEMBER
30, 1998

NET SALES

During the nine months ended September 30, 1999, the Company had net sales of
$159.0 million compared to $140.9 million in the same period of 1998. The
Company's net sales for the nine months ended September 30, 1998, include the
results of the Consumer Products Division beginning with its acquisition date of
March 6, 1998, or approximately seven months, compared to nine months in 1999.

Net sales at the Consumer Products Division was $98.3 million during the first
nine months of 1999 compared to $81.7 million during 1998. The rise in net sales
reflects a 25.5% increase in sales volume due primarily to the two additional
months of operations, partially offset by a 4.1% decrease in average selling
prices.

Net sales at the Specialty Paper Division increased $1.5 million to $60.7
million during the first nine months of 1999 compared to $59.2 million in the
same period of 1998. Improved net sales at the division reflect a 6.7% increase
in volume partially offset by a 3.0% decrease in average selling prices.

COST OF SALES AND GROSS PROFIT

Cost of sales increased to $140.2 million for the nine months ended September
30, 1999 compared to $122.6 million for the nine months ended September 30,
1998. As discussed above, the 1998 cost of sales includes approximately seven
months of costs associated with the Consumer Products Division compared to a
full nine months in 1999.

The Consumer Products Division contributed $78.9 million in cost of sales during
the first nine months of 1999 compared to $63.4 million during 1998. The rise in
cost of goods sold primarily reflects the impact of two additional months of
operations during 1999.

The cost of goods sold at the Specialty Products Division remained relatively
flat at $53.1 million during the first nine months of 1999 compared to $52.7
million during the same period of 1998, despite an increase in sales volume of
approximately 7.0%. The effect of higher volume and rising raw material prices
has been minimized by various cost savings initiatives put into place in late
1998 and early 1999, resulting in a decrease in the average cost of goods sold
on a per ton basis.

Although minimized by lower cost of goods sold on a per ton basis, the impact of
lower selling prices did result in a slight decrease in the Company's gross
profit margin to 17.0% during the first nine months of 1999 compared to 17.6% in
the same period a year ago.


                                       12

<PAGE>   13


ITEM 2. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
OF OPERATIONS, CONTINUED


SELLING, GENERAL AND ADMINISTRATIVE EXPENSES

Selling, general and administrative expenses increased $2.3 million to $14.0
million for the nine months ended September 30, 1999 compared to $11.7 million
for the same period in 1998. This increase was primarily attributable to the
March 1998 acquisition of the Consumer Products Division, whereby nine months of
expenses are included during 1999 versus seven months (since date of
acquisition) in 1998.

INTEREST EXPENSE

Interest expense increased $3.1 million to $13.2 million during the first nine
months of 1999 compared to $10.1 million in the same period of 1998. This
increase is primarily attributable to the Company's issuance of $130.0 million,
11% Senior Subordinated Notes in March 1998.

INCOME TAX EXPENSE

The Company's effective income tax rate was 27.8% and 23.6%, during the first
nine months of 1999 and 1998, respectively. The difference between the Company's
effective income tax rate and the statutory federal income tax rate are
primarily due to state income taxes.


FINANCIAL CONDITION

ACCOUNTS RECEIVABLE

Accounts receivable increased $5.1 million to $24.4 million at September 30,
1999, compared to $19.4 million at December 31, 1998. This change reflects an
increase in net sales at the Specialty Paper Division during August and
September of 1999 compared to net sales during the last two months of 1998. In
addition, a change in customer mix at the Specialty Paper Division has resulted
in a slightly slower accounts receivable turnover rate and related increase in
month end receivable balances.

ACCRUED LIABILITIES

Accrued liabilities decreased $5.5 million to $12.6 million at September 30,
1999, compared to $18.1 million at December 31, 1998. This decrease is primarily
due to the timing of the semi-annual interest payments related to the Company's
$130 million 11% Senior Subordinated Notes (the "Senior Subordinated Notes").
Accrued interest related to the Senior Subordinated Notes is due and payable on
the first day of September and March of each year.

LONG TERM DEBT

Long term debt increased $17.0 million, to $169.9 million at September 30, 1999,
compared to $152.9 million at December 31, 1998, reflecting an increase in
outstanding indebtedness under the Company's revolving credit facility.

                                       13

<PAGE>   14


ITEM 2. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
OF OPERATIONS, CONTINUED


LIQUIDITY AND CAPITAL RESOURCES.

The Company's primary capital requirements are for working capital, capital
expenditures and possible acquisitions. Management believes that cash generated
from operations, together with borrowings under its revolving credit facility,
will be sufficient to meet the Company's capital needs in the foreseeable
future.

EBITDA, a measure of internal cash flow combining earnings before interest and
income taxes plus non-cash charges for depreciation and amortization, was $14.6
million for the first nine months of 1999 compared to $14.2 million in the same
period of 1998.

OPERATING ACTIVITIES

Net cash used in operating activities for the first nine months of 1999 was $8.4
million compared to cash provided by operations of $87,000 in the same period of
1998. This change in cash used in operating activities is primarily due to
interest payments associated with the Company's Senior Subordinated Notes issued
in March 1998. Accrued interest on the Senior Subordinated Notes is due and
payable semi-annually on the first day of March and September each year.

INVESTING ACTIVITIES

Capital expenditures were $5.7 million and $2.9 million for the nine months
ended September 30, 1999 and 1998, respectively. The Company anticipates
remaining capital expenditures during 1999 of approximately $2.0 million
primarily to support various strategic initiatives. These initiatives include
new tissue converting equipment at the Consumer Products Division's facilities,
structural improvements at several facilities and enhancements of the Company's
information systems. These projects are consistent with the Company's strategy
of expanding the Specialty Paper and Consumer Products businesses, reducing
costs, and spending capital to generate a higher return on investment. Capital
expenditures are expected to be financed with internally generated cash or
through available borrowings. The Company further estimates that it will cost
approximately $5.0 million for capital improvements to bring operations into
compliance with the environmental cluster rules. The Company cannot predict if
or when the cluster rules will be promulgated in a form that will require the
Company to make such expenditures. The Company is indemnified under various
agreements with respect to certain contingent environmental liabilities.

FINANCING ACTIVITIES

The Company had $169.9 million in long-term debt outstanding at September 30,
1999, compared to $155.0 million at September 30, 1998, reflecting an increase
in borrowings under the Company's revolving credit facility. The Company had
utilized $17.6 million of the $35.0 million revolving credit facility at
September 30, 1999.

In January 1999, the Company's affiliate, Shasta Paper Company ("Shasta"),
acquired the pulp and paper operations of Simpson Paper Company. The Company
paid a dividend of $4.0 million to Shasta to finance the transaction.

Pursuant to the terms of the Amended and Restated Loan and Security Agreement
(the "Revolving Credit Facility") between the Company and Fleet Business Credit
Corporation, the Company is required to comply with various financial covenants,
including a covenant to maintain a fixed charge coverage ratio, as defined and

                                       14
<PAGE>   15


ITEM 2. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
OF OPERATIONS, CONTINUED



calculated in accordance with the Revolving Credit Facility. During the second
quarter of 1999, the Revolving Credit Facility was amended to reduce the minimum
fixed charge coverage ratio. At September 30, 1999, the Company was in
compliance with the covenants of the revolving credit facility, as amended.


INFLATION.

The Company believes that inflation has not had a material impact on the results
of operations of either the Consumer Products Division or the Specialty Paper
Division.


CONTINGENT MATTERS.

Refer to Notes 4 and 5 of the Notes to the Condensed Financial Statements for a
discussion of contingencies.


YEAR 2000 ISSUES.

The "Year 2000" refers generally to the problems that some software may have in
determining the correct century for the year. For example, software with date
sensitive functions that is not Year 2000 compliant may not be able to
distinguish whether "00" means 1900 or 2000, which may result in failures or the
creation of erroneous results. Currently, many computer systems and software
products are coded to accept only two-digit entries to distinguish the 21st
century dates from 20th century dates. As a result, many companies' software and
computer systems may need to be upgraded or replaced in order to comply with
such "Year 2000" requirements. If the Company or third parties with which the
Company does business, fail to comply with Year 2000 requirements, the integrity
and reliability of our information databases may also be adversely affected.

In connection with the March 1998 acquisition of the Consumer Products Division,
the Company entered into an 18-month Transition Services Agreement with Pope &
Talbot, Inc. for the purposes of supporting and enhancing the Consumer Products
Division's information systems and applications, including the identification,
remediation, and testing of non-Year 2000 compliant software. An additional
third party has been engaged by the Company to identify and address any Year
2000 issues at the Specialty Paper Division.

The Company has queried its significant suppliers and subcontractors which it
does not share information systems. To date, the Company is not aware of any
such third party with a Year 2000 issue that would materially impact results of
operations, liquidity, or capital resources. However, the Company has no means
of ensuring that third parties with whom the Company does business will be Year
2000 compliant. The inability of third parties to complete their Year 2000
resolution process in a timely fashion could have a material impact on the
Company's operations. The effect of non-compliance by such third parties is
presently not determinable.

Management believes that the Company has completed the necessary assessment,
remediation and testing of all business critical systems to resolve Year 2000
issues. To further reduce risk of potential Year 2000 system issues, the Company
has developed informal contingency plans for critical business applications and
is working

                                       15
<PAGE>   16


ITEM 2. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
OF OPERATIONS, CONTINUED



on additional plans for others. These contingency plans involve, among other
actions, manual workarounds and adjusting staffing strategies on a short-term
basis. The Company cannot, however, ensure that there will not be disruptions in
the economy generally resulting from the Year 2000 issues, which could
materially adversely affect the Company's operations. The amount of potential
liability and lost revenue from such disruptions cannot be reasonably estimated
at this time.


FORWARD-LOOKING INFORMATION

Certain statements in the Management's Discussion and Analysis of Financial
Condition and Results of Operation for the three and nine months ended September
30, 1999 compared to the three and nine months ended September 30, 1998 may
constitute forward-looking statements within the meaning of the Private
Securities Litigation Reform Act of 1995. Because these forward-looking
statements include risks and uncertainties, actual future results may differ
materially from those expressed in or implied by the statements. Factors that
could cause actual results to differ include, among other things; (1) Increased
competition from either domestic or foreign paper producers, including increases
in more competitive capacity through construction of new mills or conversion of
older facilities to produce competitive products; (2) variations in demand for
our products; (3) changes in the cost or availability of the raw materials that
we use, particularly market pulp; (4) costs of compliance with new environmental
laws and regulations; (5) any decisions by us to make a significant acquisition
or a significant increase in production capacity



ITEM 3.   QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK


The Company is exposed to market risks related to changes in interest rates. The
Company does not use derivative financial instruments for speculative or trading
purposes.

Interest Rate Sensitivity. The Company's earnings are affected by changes in
short-term interest rates as a result of its borrowings under its revolving
credit facility. If market interest rates for such borrowings had averaged 1%
more during the nine months ended September 30, 1999, the Company's interest
expense would have increased, and income before income taxes would have
decreased by approximately $82.0 thousand. This analysis does not consider the
effects of the reduced level of overall economic activity that could exist in
such an environment. Further, in the event of a change of a significant change
in short-term interest rates, management could take actions to further mitigate
its exposure to the change. However, due to the uncertainty of the specific
actions that would be taken and their possible effects, the sensitivity analysis
assumes no changes in the Company's financial structure.


                                       16

<PAGE>   17


PART II


ITEM 1.    LEGAL PROCEEDINGS

Reference is made to Note 7 of the Notes to Financial Statements included with
the Company's Annual Report on Form 10-K filed March 31, 1999.

ITEM 4.    SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS


(1)    None


ITEM 6.    EXHIBITS AND REPORTS ON FORM 8-K

(a)    Exhibits

The following exhibit is filed in response to Item 601 of Regulation S-K:

Exhibit No.       Description

10                Loan and Security Agreement by and between CONGRESS FINANCIAL
                  CORPORATION (CENTRAL) as lender and PLAINWELL INC. as
                  borrower, dated November 5, 1999

27                Financial Data Schedule (filed herewith)


(b)    Reports on Form 8-K
       None



                                       17
<PAGE>   18




SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the
Registrant has duly caused this report to be signed on its behalf by the
undersigned thereunto duly authorized.

PLAINWELL INC.
(Registrant)


November 12, 1999                       By: /s/ Jeffrey A. Arnesen
-----------------------------------         ------------------------------------
             Date                                 Jeffrey A. Arnesen
                                               Chief Financial Officer
                                             (Principal Financial Officer)

November 12, 1999                       By: /s/ William L. New
-----------------------------------         ------------------------------------
             Date                                  William L. New
                                            Chairman and Chief Executive Officer




                                       18

<PAGE>   19



                                  EXHIBIT INDEX

Exhibit No.       Description

10       Loan and Security Agreement by and between CONGRESS FINANCIAL
         CORPORATION (CENTRAL) as lender and PLAINWELL INC. as borrower, dated
         November 5, 1999.

27       Financial Data Schedule





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