Adrienne Saunders is happily married to her art dealer husband, Jack, and they share a daughter named Mary. Their peaceful life is fractured when the local museum curator is mysteriously murdered, and Jack falls under suspicion of having sold forged treasures to the museum. He has to travel to Boston on a work trip, but Adrienne is unsettled after a friend tells her she may have seen him in town. She confronts him, yet he insists he wasn’t there. As the pressure over a forged relic grows stronger, Adrienne learns from the police that Jack has died in a car accident. In trying to close out his affairs, she begins to suspect that her husband wasn’t the man she believed him to be. When she finds a high school yearbook photo of her husband credited to a man named Frank Sullivan, she realizes she has been deceived.
She tracks down Jack’s cousin Evelyn, who confirms that Frank and Jack were inseparable in high school. After Jack’s death, she never saw Frank again. Evelyn explains that Frank’s father was an alcoholic and his mother worked as a toll booth operator. She directs Adrienne to Frank’s mother, who lives in a rundown Brooklyn apartment. Frank’s mother, Rosalie, bitterly receives the news of her granddaughter and tells Adrienne that Frank was always selfish and never looked in on her.
A stalker lurks at Adrienne’s loft. He slips into Adrienne’s bedroom while she sleeps and caresses her, and he watches Mary, who is frightened by the man in her room at night. One day, the housekeeper finishes her chores and surprises the stalker; he leaves her nearly dead in the bathroom and ransacks the apartment.
At work, Adrienne receives an urgent message from Mrs. Sullivan and rushes to her apartment. The door is open, and Mrs. Sullivan is gone. [Jack] appears, and Adrienne slaps him for his cruelty. He explains that, after a friend’s death, he was overwhelmed and ended up adopting Jack’s identity during the mourning process. He reveals that a man named Dan Sherman is blackmailing him and that he faked his own death to escape, knowing he would have to give up his life with Adrienne and Mary. Sherman is insistent on having an Egyptian necklace in their apartment, and he asks Adrienne to locate it. As she leaves, Jack watches her from the window beside the body of his murdered mother.
During her search for the necklace, Adrienne discovers a Parks Department photo ID bearing her husband’s picture and the name Daniel Sherman. She tracks down an address and pays a surprise visit to the house. A pregnant Mrs. Sherman is on the phone and lets her in, thinking she is with a moving company. Adrienne looks around the house and sees wedding pictures of her husband with Mrs. Sherman. In a photo album, she sees a picture of Mary, whom Mrs. Sherman claims is her husband’s dead sister. The person on the phone is Jack, who asks her to hand the phone to Adrienne.
He congratulates Adrienne on uncovering his new life and reveals that he has kidnapped Mary. Mary traded the necklace to another girl, and Jack instructs Adrienne to retrieve it and meet him at their loft to exchange Mary for the necklace. At the loft, Adrienne asks to see Mary, and Jack explains that she is downstairs playing in the car. When Adrienne tries to go see her, Jack pins her against a wall and demands the necklace first. Adrienne stabs him and flees. After a long chase through a construction site, Jack corners her in the freight elevator. He reveals his creed as always doing “what comes next” no matter how difficult it is.
> what comes next
Adrienne lures Jack into the elevator shaft, where he falls to his death; Adrienne had been holding on to an unseen elevator cable to give the illusion that she was inside the elevator car. In the end, Adrienne and Mary pack their things and prepare to start a new life somewhere else.
