In San Francisco, wealthy investment banker Nicholas van Orton, estranged from his ex-wife and his younger brother Conrad, is haunted by having seen his father commit suicide on his father's 48th birthday. For Nicholas's own 48th birthday, Conrad presents him with an unusual gift—a voucher for a game offered by a company called Consumer Recreation Services (CRS), promising that it will change his life. Though doubtful, Nicholas meets fellow bankers who enjoyed the game. He goes to the CRS office to apply, but the time-consuming psychological and physical examinations required irritate him, and he is later informed that his application has been rejected. Soon Nicholas starts believing that his business, reputation, finances, and safety are endangered. He encounters a waitress, Christine, who appears to have been endangered by the game. Nicholas contacts the police, but they find the CRS office abandoned.
Eventually, Conrad appears at Nicholas's house and apologizes, claiming CRS has attacked him. With no one else to turn to, Nicholas finds Christine's home, discovering she is a CRS employee and her apartment was fake. When Christine says they are being watched, Nicholas attacks a nearby camera, and armed CRS personnel swarm the house and fire upon the pair, who flee. Christine tells him CRS has drained his bank accounts using the psychological tests to guess his passwords. His bank confirms such. He begins to feel dizzy and realizes that she has drugged him. As he loses consciousness, she admits she is part of the scam and that he made a fatal mistake in giving his card security code over the phone.
Nicholas wakes entombed alive in a Mexico cemetery, and sells his gold watch to return to San Francisco, where he finds his mansion foreclosed and most of his possessions removed. He asks for Conrad in a hotel but is told that his brother has been committed to a mental institution due to a nervous breakdown. He retrieves a hidden gun and seeks his ex-wife for help. While apologizing to her for his neglect, he learns that Jim Feingold, the CRS employee who conducted his tests, is an actor working in television advertisements. He forces Jim to find the real CRS office and takes Christine hostage, demanding to be taken to the head of CRS.
Attacked by CRS guards, Nicholas takes Christine to the roof. Christine, realizing Nicholas's gun is not a prop, frantically tells him it is a part of the game, his finances are intact, and his family and friends are waiting on the other side of the door. He refuses to believe her, and Nicholas shoots the first person to emerge—Conrad, bearing a bottle of champagne. Devastated over the accident, Nicholas leaps off the roof but lands on a giant air cushion. He is greeted by Conrad (who is alive, since the gun was indeed actually a prop, and Christine's fear of the gun faked) and the rest of the people from the game; everything had been staged by Conrad for his birthday present. Conrad intended to help Nicholas become a better person and embrace life. After a birthday party with friends, Christine declines Nicholas's offer for a date as she has another job in Australia. She offers instead to have coffee with him at the airport.
Michael Douglas as Nicholas van Orton
Sean Penn as Conrad van Orton
Deborah Kara Unger as Christine/Claire
James Rebhorn as Jim Feingold
Peter Donat as Samuel Sutherland
Carroll Baker as Ilsa
Armin Mueller-Stahl as Anson Baer
Anna Katarina as Elizabeth
Charles Martinet as Nicholas' father
Mark Boone Junior as Shady Private Investigator
Tommy Flanagan as Solicitor/Taxi Driver
Spike Jonze as Airbag EMT Beltran
Linda Manz as Amy
Daniel Schorr as himself (newscaster)