Protagonist Douglas Quail goes through three very different identities during the course of the story, as he ostensibly regresses through his recovered memories. At the beginning of the story, Quail is a dull, uninteresting office clerk who hates his boring life and whose marriage is falling apart; the only way for him to escape this reality is to dream of going Mars, which becomes a symbol of the unknown. Quail wants to go on an adventure but, more importantly, he wants to be important. When Quail dreams of Mars, he is not just dreaming of a vacation to another planet. Instead, he is dreaming of being someone more significant than his immediate surroundings would suggest.

Desperate, Quail buys a memory implant procedure from Rekal, a company that fulfills fantasies by creating fake memories. Quail’s implant will convince him that he was once an assassin who had a secret mission on Mars, a fantasy that would satisfy Quail’s desires without any of the risk. To heighten the realism, Rekal will plant physical evidence in Quail’s apartment as part of their standard procedure; this multifaceted approach effectively means that from this point of the story on, readers cannot tell whether Quail’s recovered memories are real or implanted.