Exhibit 10.12

|         |  | PROMISSORY NOTE |  |             
|-------- |  | --------------- |  | ------------
|$400,000 |  | Dallas, Texas   |  | May 31, 2002

FOR
VALUE RECEIVED, the undersigned, Thomas Group, Inc., a Delaware corporation ("Maker"), promises to pay to the order of John T. Chain, Jr. ("Payee"), at Dallas, Texas, or at such other place
as the holder hereof shall designate from time to time in writing, in lawful money of the United States of America, the principal sum of Four Hundred Thousand and No/100 Dollars ($400,000), and to pay
interest from June 1, 2002 on the principal balance hereof from time to time remaining unpaid prior to maturity at the prime rate of interest from time to time in effect at Dallas, Texas (which
rate shall change from time to time when and as such prime rate of interest shall change) plus six percent (6%) per annum, such interest payable semi-annually on December 1 and
June 1 of each year. All past due principal and interest shall bear interest at the higher of such rate or eighteen percent (18%) per annum until paid. The interest hereon shall never be
charged or collected at a Highest Lawful Rate (as defined herein).

The
entire principal of this Note and accrued interest thereon shall be due in full on June 1, 2004.

Except
as otherwise provided in this Note, the undersigned waives demand, presentment for payment, protest, notice of protest, notice of intention to accelerate, filing of suit, and
diligence in collecting this Note.

If
this Note shall be collected by legal proceedings or through a bankruptcy court, or shall be placed in the hands of an attorney for collection after maturity, no matter how maturity
is brought about, the undersigned agrees to pay reasonable attorneys' or collection fees incurred by Payee in connection therewith.

This
Note shall be construed in accordance with and governed by the laws of the State of Texas.

The
undersigned shall have the right to prepay the principal in whole or in part from time to time without premium or penalty.

This
Note shall become and be immediately due and payable upon the written demand of the holder hereof to the Maker if one or more of the following events shall happen and be continuing
at the time of such demand:



Any
notice or demand required to be given hereunder by any holder hereof shall be deemed to have been given and received (1) when actually received by Maker, if delivered in
person, or (2) forty-eight (48) hours after a letter containing such notice is deposited in the United States mail, certified or registered, with postage prepaid, and addressed to Maker
at 5221 North O'Connor Boulevard, Irving,

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Texas, 75039, or at such other address of Maker as Maker shall advise the holder hereof by certified or registered mail.

This
Note and all other agreements between Maker and Payee are hereby expressly limited so that, in no contingency or event whatsoever, whether through acceleration of maturity of this
Note or otherwise, shall the amount paid or agreed to be paid to the Payee for the use, forbearance or detention of the money advanced or to be advanced hereunder exceed the highest lawful rate
permissible under the laws of the State of Texas as applicable to this transaction. If, from any circumstances whatsoever, fulfillment of any provision hereof, at the time performance of such
provision shall be due, shall involve the payment of interest in excess of the Highest Lawful Rate, and
if from any circumstances the holder hereof shall ever receive as interest an amount that would exceed the Highest Lawful Rate, the amount that would be excessive shall be applied to the reduction of
the unpaid principal balance of this Note (and not to the payment of interest) or if such excessive interest exceeds the unpaid balance of principal of the Note, the excess shall be refunded to Maker,
and the holder hereof shall not be subject to any penalty provided for the contracting for, or charging or receiving of, interest in excess of the Highest Lawful Rate regardless of when or the
circumstances under which such refund or application was made.

In
the event that, subsequent to the date hereof, Maker obtains financing from any third party source, whether in the form of debt or equity, Maker and Payee agree to amend this Note and
enter into such other documentation as is necessary for Payee to receive consideration for the loan evidenced by this Note on terms and conditions no less favorable to Payee than those provided to
such third party. By way of illustration but not of limitation, should such third party source receive equity securities or securities convertible into equity securities of Maker in connection with a
financing, Payee shall receive the same on the same terms and at the same price.

EXECUTED
as of the day and year first above written.

| |  | THOMAS GROUP, INC.
| |  | ------------------
| |  | By:               
| |  | Name:             
| |  | Title:            

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