Sleepwalker

After her husband's suicide, Sarah Foster begins sleepwalking and is sent to a sleep clinic for evaluation. Dr. Koslov and Dr. White monitor her brain activity as she endures a night of dreamless sleep, waking up in a bizarrely different room. Koslov informs her she has been moved for continued observation and should stay longer.

A professor and her roommate Dawn start calling her 'Miss Wells,' and her documents identify her as Sarah Wells. Koslov shows a form about a dream of being chased, but Sarah insists she never dreamed and questions the handwriting, which she says matches hers. The discrepancy deepens the mystery of who she really is.

She searches for information on selective memory loss and learns about partial retrograde amnesia. The medical explanations hint that memories can be altered or misattributed in sleep disorders, foreshadowing how her experiences may blend with someone else's. The idea plants seeds about a fragile sense of self.

Back at home, Sarah finds her roommate replaced by a stranger named Nicole and receives a phone call from a man who claims to know her. Dr. Cooper does not recognize Sarah, further eroding her grip on reality. That night, she dreams of being suffocated.

The next morning, she wakes to find herself locked out of her apartment and discovers Nicole inside with another girl. After breaking in through a window, she sees unfamiliar belongings in her room and a taunting man on the phone. She hides in the laundry room as water seeps under the door, realizing the events could be intruding on her waking life.

Dawn returns to a normal routine, but White explains that sleep issues can warp perception of reality. A dark-haired man begins chasing her on the street, but White intervenes and offers her a ride, framing dreams as a way to understand her emotions. This guidance hints at a deeper connection between dreams and danger.

She dreams of being trapped in plastic and wakes to find herself back in the strange house, where she is confronted by a fearful woman. The dream imagery begins to bleed into her waking life, blurring the boundary between fantasy and reality.

Back in the lab, Koslov does not recognize her and another man named White claims to know her. During a campus lecture, a woman in the audience recognizes Sarah, confirming that others are aware of her under circumstances she does not grasp.

After evading the police outside her apartment, she hides in the laundry again as water starts to seep in, signaling that the boundary between dream and reality is breaking down. The tension suggests someone is manipulating her environment from afar.

She wakes in the sleep laboratory to learn that the police found she has been sleepwalking; she cannot recall the events, but data shows she was dreaming. White suggests that the stalker might help connect two conflicting realities, hinting at a sinister link between her waking life and dreams.

Back home, Sarah reads a diary and discovers that Jonathan was murdered, not the suicide she believed. This revelation reframes her memories and deepens the mystery of who is manipulating her life. Cooper advises protection as the strain of memory returns.

The truth finally emerges: Sarah realizes she is actually Anna Wells, the obsessive fan who shot Jonathan, while the original Sarah Foster is the man’s true partner. Flashbacks reveal Anna's coma and her struggle for breath, trapped inside her mind as she mistook her identity.