Seemingly uncertain of their ultimate destination, the two talk about their plans for the future. When their bus breaks down, the two acquire a car from a nearby garage. While Martin is driving, a tire blows. Matt struggles to change the tire and Martin comments on how he and Matt are both about the same height, and kicks Matt into the path of an oncoming truck, killing both him and the driver.
Taking Matt's guitar and clothes, he walks away singing in a voice similar to Matt's. Twenty years later, a successful FBI profiler , Illeana Scott Angelina Jolie , is summoned to help out the authorities in Montreal in apprehending a serial killer who assumes the identities of his victims, enabling him to travel undetected across North America. Martin's mother Rebecca Gena Rowlands claims to have seen her son alive and well on a ferry to Quebec City , leading to the body believed to have belonged to him being exhumed for forensic examination, and he becomes the primary suspect.
Illeana, who has difficulty adjusting to her new surroundings and is distrusted by her local colleagues, interviews art dealer James Costa Ethan Hawke , an eyewitness who saw Asher kill his last victim. Costa makes a drawing of the killer and the authorities manage to track down the man's apartment, only to find a decaying corpse chained up in the ceiling. Illeana goes to Rebecca's house to question her about her son, and while snooping around discovers a hidden passageway behind a cabinet that leads to a secret room used to house young Martin, an unwanted and unstable younger child whom Rebecca neglected and saw as inferior to her elder son, whom Martin ultimately killed out of jealousy.
Illeana is attacked by a hidden assailant, who escapes before she can identify him. Illeana determines that Asher is targeting people whose lives hold something his current one lacks, and that his latest target is Costa after his apartment is broken into and ransacked.
Costa is subsequently used in a sting operation to lure and apprehend Asher, but the operation fails and Costa angrily refuses to be used as bait.
During a show at his gallery, Costa is attacked by an assailant Kiefer Sutherland , whom Illeana tries to apprehend, but loses in the crowds after a foot chase outside.
For his protection, the police decide to move Costa out of town, but the next morning Costa is confronted by the same assailant, who attacks him and demands to have "what he wants.
Illeana gives chase, and causes the car to crash and explode just as Costa manages to escape. As Illeana is preparing to return home, Costa visits her in her hotel room. The two, having grown close over the course of the investigation, make passionate love on a chest of drawers and the bed, surrounded by gruesome crime scene photos. The next morning, Illeana awakes to find herself partly covered in Costa's blood. At first, she fears he is dead, but then he awakes, and they discover he had merely popped the stitches in his arm that he received after the auto accident.
As Costa's stitches are repaired in the hospital, Scott is called down to the morgue as Rebecca has come to identify the charred body of the assailant. She's unable to confirm the body as Martin, and Illeana realizes that Asher must still be alive.
Shocked, Rebecca leaves the morgue, and goes to the elevator, as Illeana chases after her. Before she can reach her, the elevator door closes, and Costa confronts her, revealing himself as the real Martin Asher. Costa kills his mother, and Illeana sees him covered in blood just as the elevator door between them closes. The police try to capture Asher who escapes the hospital.
Scott returns to her hotel room and frantically washes herself, in a state of manic disgust. The police chase Asher, but he escapes in a train station and boards a train headed east of Montreal , meanwhile setting up his next victim, a sports talent scout.
He calls Illeana on the phone and taunts her before hanging up and disappearing into the crowd of other passengers. Illeana admits to having consensual sex with Asher, and is consequently fired from the FBI. Seven months later, Illeana is living in a desolate farmhouse by herself in Carlisle , Pennsylvania and looking heavily pregnant with Asher's twin boys.
One day as she sits alone in her home, she discovers Asher has broken into her house. She frantically tries to escape, but Asher quickly overpowers her and then reveals he has found all the guns she had hidden throughout the house. Asher makes her tea and tells her they could start over and live together as a family, but a disgusted Illeana tells him she does not want to. Enraged, Asher begins beating and choking her and eventually stabs her in her belly with a pair of scissors.
Illeana, seemingly unharmed by the stabbing, shocks Asher by quickly stabbing him in the heart with the same scissors. As Asher is on his knees looking at her in disbelief, Illeana removes a prosthetic pregnant belly, and tells him the past seven months have been a carefully planned trap. Angelina Jolie as Illeana Scott: She discovers the crimes are all from the same killer, and begins the search for a sociopath.
Ethan Hawke as Martin Asher: After the death of his twin brother, Reese, during the pair's childhood, Martin was confined to a cellar room by his mother, who had favored Reese. Martin hates himself and his identity as a result of his mother's favoritism and death of his brother, beginning his slew of murders; assuming and taking the lives of his victims.
Through of the film's plot he impersonates and acts as a painter, named James Costa. Kiefer Sutherland as Christopher Hart: Gena Rowlands as Mrs. After her son Reese died trying to save Martin from drowing, Mrs. Asher became depressed and neglected Martin.