<PAGE>


                                                                   Exhibit 10.78
                                                                   -------------

                [TRUMP HOTELS & CASINO RESORTS, INC. LETTERHEAD]





August 4, 2000


Mr. Mark A. Brown
[ADDRESS]

Re:      Second Amendment of the Employment Agreement dated March 6, 1998
         between Mark A. Brown and Trump's Castle Associates, as assigned to
         Trump Taj Mahal Associates and amended effective as of January 3, 2000
         the "Agreement")

Dear Mr. Brown:

This letter will confirm our agreement to further amend the Agreement as
follows:

1.       This Amendment shall be effective as of July 1, 2000, and the
         Expiration Date shall be July 31, 2003, subject to Trump's option
         pursuant to new Paragraph 13.a. below.

2.       Paragraph 1 is hereby amended to confirm your employment as President
         and Chief Executive Officer of each of Trump Taj Mahal Associates,
         Trump Plaza Associates, Trump's Castle Associates and Trump Indiana,
         Inc. (subject to necessary licensing by the Indiana Gaming
         Commission).

3.       In consideration for this Amendment, Paragraph 2.a, as previously
         amended, is hereby deleted in its entirety and replaced as follows:

                      a.   During the term of this Agreement, you shall be paid
                           an annual salary at the rate of One Million
                           ($1,000,000) Dollars commencing effective as of July
                           1, 2000, payable periodically in accordance with
                           Trump's regular payroll practices. Said annual salary
                           shall increase to One Million One Hundred Thousand
                           Dollars ($1,100,000) commencing January 1, 2001 and
                           to One Million Two Hundred Thousand ($1,200,000)
                           Dollars commencing January 1, 2002.

4.       Paragraph 13 is hereby deleted and replaced in its entirety with the
         following:

                     a.    Trump, in its sole discretion, shall have the right
                           and option to extend the Expiration Date to July 31,
                           2005. Trump agrees to notify you in writing one
                           hundred and eighty (180) days prior to the Expiration
                           Date as set forth herein of Trump's decision to
                           exercise such option. In the event Trump exercises
                           such option, your annual salary shall be

<PAGE>

Page Two

                           One Million Three Hundred Thousand ($1,300,000)
                           Dollars commencing August 1, 2003 and shall increase
                           to One Million Four Hundred Thousand ($1,400,000)
                           August 1, 2004. In the event you are not notified of
                           Trump's exercise of such option to extend said
                           Agreement as provided herein, you shall be free to
                           contact other potential employers and to discuss
                           possible employment to begin after the Expiration
                           Date.

                     b.    In the event Trump exercises its option pursuant to
                           Paragraph 13.a. and extends the Expiration Date as
                           provided therein, Trump agrees to begin negotiations
                           for any further extension or renewal of the Agreement
                           no later than January 31, 2005. You agree to notify
                           Trump within ninety (90) days of the provision of
                           said proposed extension or renewal of the Agreement
                           as to whether the proposed terms are acceptable or
                           whether you are requesting amendments or further
                           modifications. In the event you are not notified of
                           an intent to renew or extend said Agreement as set
                           forth herein, you shall be free to contact other
                           potential employers and to discuss possible
                           employment to begin after the Expiration Date.

5.       Paragraph 14.a.(ii) is hereby deleted in its entirety.

                           Except to the extent modified herein, you hereby
                           ratify the Agreement and agree that all other such
                           terms, conditions and obligations contained therein
                           remain in full force and effect as stated in the
                           Agreement.

                                               Very truly yours,

                                               /s/ Donald J. Trump
                                               -------------------
                                               DONALD J. TRUMP
                                               Chairman
                                               Trump's Castle Associates
                                               Trump Taj Mahal Associates
                                               Trump Plaza Associates
                                               Trump Indiana, Inc.

DJT/vls

Agreed to this _____ day of July, 2000

/s/ Mark A. Brown
-----------------
MARK A. BROWN