College student Stephan and his friend Karen unpack at the new house that he's moved into. As they work, Stephan says that he just felt at home there when he chose the place, and seems to know what furniture belongs where. As they talk, Stephan has flashes of the house like it was in the 1920s, and someone carrying a knife. When he snaps out of his apparent flashbacks, Stephan realizes that he's unpacked almost everything during his blackout. The only thing left to unpack is a box of books and papers, and Stephan tells Karen that it's his dissertation research and he'll do it later.
Karen suggestively offers to order a pizza with him and stay late, but Stephan backs out and says that he'll walk her home. As he goes to the elaborately decorated bathroom to wash up, Karen follows him in. As Stephan cleans up, he suddenly gets an image in his head of Karen wearing a bathrobe and someone stabbing her. When he snaps out of it, Karen is dressed normally and says that she didn't see anything, and Stephan dismisses it as his imagination.
The next day, Stephan is unpacking and finds a kitchen knife like the one he saw in his flashback. He hears music playing on an old-fashioned gramophone and gets more of flashes of a woman in the parlor and a man holding a switchblade knife to her throat. Someone that sounds like Karen calls to Maxie from the bathroom and Stephan goes to investigate. The woman, Zelda, looks just like Karen and is the woman Stephan saw in the bathrobe earlier. She can't see Stephan and he assumes it's his imagination again. As he brushes his teeth, Stephan realizes that he's holding the switchblade knife. Zelda emerges from the blood tub, begging for help, and Stephan sees someone grab her and thrust her back under.
Later, Stephan meets with Dr. Wolfram, his therapist. They discuss his love life and he admits that he feels comfortable with Karen and would like more with her than just friendship, but he suffers from panic attacks. When Stephan talks about his blackouts and flashbacks, Wolfram wonders if they might be repressed childhood memories of some trauma his patient had with a woman. Stephan doesn't believe it but Wolfram hypnotizes him and takes him back in his memories.
Once hypnotized, Stephan sees Zelda taking a bath and singing. Stephan realizes that he's her 1920s boyfriend, Maxie, and sees himself as Maxie when he looks in the mirror. Maxie/Stephan then goes to the bathtub and kneels by Zelda.
In the doctor's office, Wolfram has Stephan describe what he's seeing and records it. Afterward, he plays it back for Stephan and the listen as "Maxie" says that he's angry at Zelda and would gladly kill her. Stephan takes a CD of the recording back to his home and listens as Maxie says that he's a former boxer turned enforcer who is good with a knife. In the recording, Wolfram talks to Maxie, who says that he was born in 1893 and that the year is 1928. As Maxie talks about wanting to kill Zelda, Karen comes in and startles Stephan. They play Scrabble and share a bottle of wine, and Stephan asks her if she believes in reincarnation. Karen dismisses it as all make-believe and then wins the game with the word "bloodbath," and Stephan flashes back to seeing Zelda/Karen dying in the bathtub.
That night, Stephan wakes up when he hears Zelda and Maxie talking in the parlor. He goes down and sees the couple playing cards. When Maxie hints that Zelda's a whore, she takes offense and then wins the game. He holds his switchblade knife to her throat and Zelda dares him to do it. After a moment, Maxie pulls the knife back and kisses her.
At his next session, Stephan tells Wolfram what he saw. He believes that Maxie is someone he was in a past life and Wolfram hypnotizes him again. Maxie takes over and describes a party that Zelda held at the house.
Zelda flirts with the men while the party breaks out into an orgy. One man, Butler, dances with Zelda and then offers her a part in the pay he's producing. When Zelda realizes that Maxie is watching, she flirts back to make her boyfriend jealous. When Butler leaves, Maxie follows him, beats him unconscious, and then stabs him to death.
When Stephan comes out of the trance, he tells Wolfram that he felt afraid of what he now believes he's capable of. The doctor assures him that what he saw was a subconscious metaphor, not a past life, but Stephan isn't convinced.
That night, Stephan comes home and discovers that Karen has decided to host a housewarming party, inviting their ates and teachers. She's found a 1920s flapper dress and is talking to Professor Butler, who looks just like the Butler that Stephan saw Maxie kill. Butler and Karen talk and she flirts with the professor to make Stephan jealous. He complains that she's drunk and Karen admits that she is. Stephan continues to watch, what he's seeing mixing with his memories of Maxie at the 1920s party. When Butler goes to his car, Stephan beats him unconscious. He goes home and finds Karen waiting for him in his bed. She says that she's been waiting for him his entire life as if they were destined to be together.
After the party, a blood-covered Maxie returns to the house. Zelda initially tries to refuse his advances, but they go to bed and make love. Once they're done, Maxie confesses his love for her and she begs him not to ever leave her. He assures her that nothing will ever keep them apart.
Stephan walks to the bed, grabs Karen as she gets up, and throws her back onto it.
The next morning, Stephan wakes up in his bed, plagued by visions of Maxie killing Zelda. Assuming the previous night was another dream, he calls Karen on his cell phone. She answers and he asks what happened to Butler, and Karen tells him that Stephan insulted the man's book. She then comes into the bedroom, startling him, and Stephan realizes that he didn't imagine them making love the previous night. Thinking that he doesn't think anything of them being together, Karen starts to storm out. Confused, Stephan calls her "Zelda" and Karen demands an explanation.
Stephan goes in for another session with Wolfram and tells him what happened. When Wolfram figures that Stephan's story about Zelda's death scared her, Stephan admits that he didn't tell Karen that part.
While Stephan is out, Karen goes to the house and finds his box of dissertation research. It's full of 1920s books and magazines, including playbills and publicity photos of Zelda and newspaper articles about the party. When Stephan arrives, talking like Maxie in a threatening tone, Karen tells him that Zelda is a real person and that he knew it because he had done the research. Stephan flies into a rage, saying that he hasn't seen any of the material. Karen tells him that they found the beaten Butler in an alley after the party, but he wasn't able to identify his attacker. Disgusted, Stephan says that Butler deserved what he got.
At his next session, Wolfram continues to insist that Stephan's subconscious is creating metaphors, but the student insists that what he's seeing and feeling is real. He believes that Maxie is trying to do things over again and ask the doctor to help him figure out why.
When Zelda comes back home, she discovers that Maxie has made her supper. They end up in the bathtub but when she angers him again, Maxie goes to get his switchblade knife.
When Stephan comes out of his trance, Wolfram tells him to get out of the house. Stephan insists that Maxie has been reborn in him and Zelda in Karen. He toys with a letter opener and repeats his theory that Maxie is taking control and wants to do things over again. Wolfram tries to calm him down but Stephan shoves the psychiatrist down on his desk, grabs a letter opener, and holds it to the man's eye.
Karen comes back to the house to get her cell phone and Stephan asks her to stay for dinner. He apologizes and says that he's been spending years loving her from a distance, and now he wants to make up for lost time. After supper, Stephan suggests that she take a bath. As they move to the bathtub and Karen gets in, she says that it feels like déjà vu. Stephan smells cigarette smoke on her blouse and accuses her of sleeping with Butler. Angry, Karen claims that she's slept with most of the faculty and Stephan storms at him. Karen screams at him that she hates him while Stephan goes to the kitchen and gets a knife.
Maxie comes back with his switchblade knife and looks in the mirror. He can't see Zelda, but he finds Stephan's face staring back at him and drops the knife, startled.
Stephan comes back with the knife and can't see Karen. He finds Maxie's face staring back at him in the mirror and drops the knife, startled.
Zelda comes in to apologize but Maxie orders her out, calling her a whore. Furious, Zelda grabs the knife and stabs her boyfriend in the chase.
Stephan clutches at a sudden pain in his chest.
Maxie grabs Zelda and then pulls the knife out of his chest.
Karen comes in and apologizes, and then reaches down for her clothing. Stephan thinks that she's going for the knife, grabs it himself, and threatens to kill her. Karen breaks his thumb and he drops the knife into the bathtub. Karen manages to get it first and Stephan comes at her... and impales himself. Startled, he pulls the knife out of his chest and then dies in Karen's arms.
Maxie dies in Zelda's arms.