Douglas Quail is an ordinary government clerk leading a rather unexciting life. Quail’s biggest dream has always been to visit Mars, but is continuously discouraged by his wife, who is irritated by this fantasy, and by his insufficient salary. Still unable to brush off his obsession, he discovers Rekall, Incorporated, a company that implants false memories into the brains of paying customers. He makes an appointment at Rekall and meets with the lead scientist, McClane to discuss the details of the implantation. Quail decided to receive the memory of a two week trip to Mars as an undercover Interplan agent. As the implantation takes place, the scientists discover an implant already planted in his brain that erased real memories of his real visitation to Mars as an agent.
This discovery blew a government secret. McLane terminates the implantation, refunds half of Quail’s money and sends him home. However, Quails believes the memories to be false and demands for a full refund. After returning home he locates a box full of fauna from Mars in his desk, which sends him spiraling down a hole of uncertainty.
He confronts his wife about the memories which results in her angrily leaving him. Just moments after two armed men enter and reveal that Qauil has a tele-transmitter in his head which enabled them to understand his thoughts. Quail then remembers the reason for the removal of his memories: Quail was a trained assassin who killed a man on Mars. Using his newly remembered skills, Quail fights both men and escapes.
Now, frightened about his true past, Quail tries to run for his life; however, he is contacted by former commanders through the transmitter. The commanders convince him to surrender under one condition: providing him with a new, stronger set of memory implants and removing his old. Quail allows Interplan to capture him and eventually figures out his preferred memory. In the new implants, Quail protects Earth from an alien invasion and only his continued survival keeps the invasion from happening. As they perform the transplant again, McLane discovers the memories maybe true as well.
The story ends with everyone hesitant of what to do with Quail.