In the future, Douglas Quaid (Arnold Schwarzenegger) keeps dreaming about Mars, even though he has never been there. He also dreams about a mysterious woman (Rachel Ticotin) he has never met, much to the concern of his wife (Sharon Stone). On a whim he visits a company that can implant the memories of a vacation, and chooses a "trip" to Mars. The process goes wrong, and perhaps unlocks something inside Quaid's brain. People begin chasing him, and he decides to travel to Mars to find out what's going on. He finds evidence of his previous identity, "Hauser," and some clues to what's really going on: It all ties into a plot to control the air supply on Mars. But how many layers does this mystery have, and how can Quaid tell what's real?