Stafford Farms (Stafford) (defendant) leased its property to Mike Hatley (plaintiff) for about ten months for the purpose of growing wheat. The agreement contained a buyout provision, under which Stafford could buy out Hatley at a price of not more than $70 per acre. Nearly seven months into the lease, Stafford took possession of the farm and cut the wheat crop, claiming it was exercising its buyout option. The fair market value of the wheat at the time was $400 per acre. Hatley brought suit for trespass, alleging that the parties had orally agreed that the buyout provision was only to apply for a period of 30 to 60 days after the execution of the lease. The restriction on the buyout provision was not contained in the handwritten agreement which was drafted by the parties. Stafford objected to the introduction of this alleged oral agreement on the basis of the parol evidence rule. The trial court allowed the evidence to be admitted under the partial integration doctrine. Stafford appealed.