On June 10, 1977, Willard R. Hield (plaintiff) sold his interest in a corporation to his partner, Edwin R. Thyberg (defendant). The parties executed an agreement (Assignment) that provided that Hield was transferring his interest in consideration for $15,000.00 from Thyberg. In January 1979, Hield brought suit against Thyberg. At trial, Hield sought to introduce parol evidence showing that Thyberg agreed to pay an additional $35,000.00 in the form of a promissory note, in addition to the $15,000.00 stated in the Assignment. Thyberg’s objection to the parol evidence was overruled. Hield testified that the parties had not listed the additional $35,000.00 as consideration in the Assignment because they did not want to prejudice a loan for which Thyberg intended to apply. The trial court ruled in favor of Hield and judgment was entered for $35,000.00 plus interest.