Jennings (Affleck) is an engineer who works for a company and uses their rivals technology, alters it slightly, and has his memory wiped after each job. When he is offered a job by James Rethrick (Eckhart), he is told that the job will take three years and his mind will be wiped afterwards. Against the advice of his friend Shorty (Giamatti), he takes the job. When his mind is wiped, he heads to the bank to collect his multimillion fee where it turns out that he, during the erased three years, signed the money away and exchanged it for a group of nineteen seemingly worthless items. This film follows his efforts to uncover the secret of just what he was working on, what the items are for, evading arrest, and exploring his relationship with Rachel Porter (Thurman), a bioscientist, who is a vital part of triggering what is left of the scraps of memory left to him.