Malcolm Rivers has been convicted as the perpetrator of several murders and is sentenced to death. An eleventh hour defense by his lawyers and psychiatrist that Malcolm is insane based on new evidence has resulted in them meeting with the prosecutors and the judge to discuss if the verdict should be overturned. Meanwhile, on a dark night during a torrential rainstorm in the Nevada desert, a series of chain reaction events results in several people needing to stay at an out of the way motel managed by Larry. They are: ex-cop now limo driver Ed, and his client Caroline, a diva of a once famous actress; quiet adolescent Timmy, his stepfather George, and his mother Alice, who was seriously injured when Ed accidentally ran over her as she watched George change their flat tire; prostitute Paris, who was the unwitting cause of George's flat tire; newlyweds Lou and Ginny, whose marriage is based on a lie; and Police Officer Rhodes, who was en route escorting prisoner Robert to his new institution. They all can't leave the area because of washed out roads, all the other businesses around the motel are closed because of the storm, and all communication in and out is not functioning also because of the storm. One by one, they are murdered, the murderer leaving a calling card of a motel room key, starting with the room 10 key and working his way presumably to the room 1 key when the last person will be dead. Those still alive band somewhat together under Officer Rhodes and Ed's direction to find out which of the eleven is the murderer, and if, based on one of their theories, that they were brought to the motel by some force by the murderer as his intended targets. Whether those still alive can discover who the murderer is, discover why he has chosen to kill them, and be able to subdue him may well determine Malcolm's fate.
Strangers from all different walks of life: a limo driver escorting a fading television star, parents with a young son whose marriage is in crisis, a cop transporting a dangerous convict, a beautiful call girl, a couple of young newlyweds, and a nervous motel manager are caught up in a severe rainstorm, stuck at a motel in desolate Nevada. Soon they realize they may be at the motel for another reason when one by one, people start getting killed off. As tensions flare and fingers are pointed, they have to get to the bottom of why they're there. Meanwhile in an undisclosed location, a psychiatrist is trying to prove the innocence of a man accused of murder in an eleventh hour trial. How these two through-lines are related can only be found in Identity.
Stranded at a desolate Nevada motel during a nasty rain-storm, ten strangers become acquainted with each other when they realize that they're being killed off one by one.
- Malcolm Rivers (Pruitt Taylor Vince) is a psychotic killer awaiting execution for several vicious murders. His psychiatrist, Doctor Malick (Alfred Molina), has discovered a journal belonging to Rivers that may explain why he really committed the murders. With this late evidence brought forth, a new hearing takes place on a stormy night in which Malick will try to persuade the Judge to spare Rivers.
Meanwhile, a group of ten strangers, through a number of circumstances, find themselves stranded in the middle of a storm in a remote motel in the Nevada desert. With the phone lines down due to the storm, the group prepare to spend the night, taking care of those that have been injured through their arrival. However, the group quickly finds that there is an unknown murderer present, killing off each of the guests and leaving behind one of the motel's room keys to be found, starting with Room 10's key and counting down.
Back at the hearing, the contents of Malcolm's journal are revealed, indicating the prisoner suffers from an extreme case of Dissociative Identity Disorder, harboring ten distinct personalities. Malick is able to bring forth one of Malcolm's personalities, Ed (John Cusack), revealing that events at the motel are occurring inside Malcolm's mind, each personality being a distinct person though all sharing the same birth date. After hearing of events in the motel, Malick informs the Ed personality that he must find and eliminate the hostile personality in order to prevent Malcolm from being executed lest all the personalities be killed off.
In the motel setting, as the group is dwindled down, Ed believes that the personality of Rhodes (Ray Liotta) is the murderer, and sacrifices himself to kill Rhodes, leaving only Paris (Amanda Peet) alive.
When Malick demonstrates that that homicidal personality is dead, the judge decides to place Malcolm in a mental institution under Malick's care.
As Malcolm is driven along with Malick to the institution, in Malcolm's mind, Paris has driven away from the motel to her hometown in Florida. As she tends an orange grove, she discovers the Room 1 motel key in the ground, and turns around to find the young boy Timmy standing behind her. Timmy, the true homicidal personality, had orchestrated all the deaths at the motel, and made it appear that he had been killed as well; he finishes his task by killing Paris, reciting Hughes Mearns's Antigonish.
Now driven only by his last personality of Timmy, Malcolm strangles Malick, and the transport van runs off the side of the road.