Sometime in the near future, where deceased or sick pets can be cloned into exact duplicates with all of the memories and personalities of the original, but similar human cloning is banned, Adam Gibson (ARNOLD SCWARZENEGGER) is a happily married pilot and partner of the Double X Charter Company, a futuristic helicopter service that transports clients to snowy environs.
While his partner and best friend, Hank Morgan (MICHAEL RAPAPORT), enjoys the company of a virtual girlfriend, Adam is old-fashioned when it comes to technology outside of work. He finds those stances challenged when his daughter, Clara (TAYLOR ANNE REID), wants a mostly realistic looking and behaving Sim-Pal doll, while his wife, Natalie (WENDY CREWSON), urges him to replace their dog that was just put to sleep with a cloned replacement from RePet.
Knowing he has time to kill before Natalie throws him a "surprise" birthday party, Adam heads off to look into both while Hank sets off with multi-billionaire Michael Drucker (TONY GOLDWYN) who runs Replacement Technologies, a firm designed to replenish the world's food supply through advanced cloning.
Since human cloning is illegal, various factions see Drucker and his chief scientist, Dr. Griffin Weir (ROBERT DuVALL) -- whose wife, Katherine (WANDA CANNON), is terminally ill -- as dangerous and thus put a hit out on Drucker.
After experiencing an odd sensation while on his way to RePet, Adam returns home only to find to his shock that Natalie and others are already celebrating his birthday with him inside their house. He doesn't have much time to think about that, however, as Robert Marshall (MICHAEL ROOKER), the head of Replacement Technologies security and his cronies, Talia Elsworth (SARAH WYNTER),
Wiley (ROD ROWLAND) and Vincent (TERRY CREWS), arrive on the scene and try to capture and kill him.
Eventually discovering that he's been cloned and that his family will be killed if they see him and his clone together, Adam must then figure out who cloned him and why, all while avoiding Marshall and his thugs who repeatedly return as new clones every time he kills them.