Douglas Quail, a simple and ordinary man, wishes to visit Mars. Unable to afford it, he visits a company, Rekal, that offers implanted memories ("extra-factual memory"). The attempt to implant some racy Mars memories of Quail as a secret agent, reveals that Quail actually is an undercover government assassin with a mind full of dangerous secrets. The Rekal staff quickly get Quail out of there; he heads home and finds certain physical evidence to support his new old memories. The government initially seeks his death but instead Quail manages to make a deal. He returns to Rekal to have his Mars memories once more suppressed, and is offered by way of compensation a set of heroic wish-fulfillment false memories. The Rekal staff begin the memory-implanting procedure — and uncover a different and older set of suppressed memories revealing that the unbelievable memories they are about to insert are already there and are true.