Rachel Darwin, a pregnant woman facing a career crossroads, experiences recurring dreams of a shadowy man in a fedora who forcibly removes a deformed baby from her womb. When she searches online, she uncovers a hidden community of night sufferers who are visited by watchers while they sleep. Her husband Scott Darwin worries these visions are merely hallucinations born from a subconscious wounded by past infidelity and a fear of childbirth. Yet Rachel is convinced the encounters are real: she begins to suffer sleep paralysis, and she even catches glimpses of the same malevolent figure, the so‑called Hat Man, during waking moments—a distorted blur in a photo or a fleeting flicker at the edge of her eye. She fears she is being stalked by something truly malevolent.
In a regular group therapy session for recovering addicts, Rachel Darwin finds an ally in a peculiar man named William, who believes he has endured similar sleep paralysis and visions. As she opens up, she and William form an unlikely bond, with William sharing unsettling theories about multidimensional beings that surround everyone and feed on human souls. His ideas push Rachel to question the nature of her experiences and to seek a deeper understanding of the danger she faces.
The nightmares intensify and begin to bleed into Rachel’s waking life, dragging her into disturbing visions of her past. In an attempt to help her escape the fear and to repair their strained relationship, Scott invites Rachel on a weekend retreat to a remote winter cabin, hoping the isolation will soothe her and rekindle their romance.
Meanwhile, William keeps digging into his own evidence, examining photographs he secretly took of Rachel at group sessions. To his alarm, he sees the Hat Man looming behind her in several images. Back in the city, Rachel continues to dream of the Hat Man at night, and she also notices fleeting sightings of him during the day. Frustrated by her perceived distance and erratic behavior, a drunken Scott tries to forcefully assault her. In a desperate moment, Rachel knocks him unconscious and drives away in their car, seeking safety in the city.
Rachel spends the night at William’s apartment. He shows her the photographs, but the Hat Man is not present in these images. She discovers the same absence in photos she herself has taken, which strengthens her belief in William’s theories. The two grow closer, and their physical closeness deepens the bond, with William convinced that together they can expose and stop the shadow figure.
The following morning, Scott realizes Rachel has been seen with William and arranges for help. He relies on his legal assistant, Sally, to help him navigate the situation as he hunts for William’s address. The next step in the plan shifts toward the subconscious: William hypnotizes Rachel to probe her deeper memories and confront the shadow figure head-on. Through the trance, Rachel experiences a vision of the Hat Man removing the baby once more, and she is shown a doorway into her childhood home, including a moment when her mother dies by suicide. She witnesses William’s apartment and the process of her own hypnotic session, and William realizes that Rachel may be astral projecting. In a chilling sequence, the Hat Man materializes and kills William in a supernatural act. Rachel, desperate to wake herself from the trance, stabs herself, only to discover that William has indeed been murdered.
Scott arrives at William’s place, but finds the door locked and no way to reach Rachel. The Hat Man launches an attack, and Rachel struggles to defend herself, wrenching the knife from him and delivering a fatal stab as the figure dissipates. Scott pleads with Rachel through the locked door, only to learn that her belly is bleeding. The Hat Man returns from the shadows and murders Rachel in front of him. The door finally unlocks on its own, revealing the two corpses.
Scott is arrested for the murders, and the interrogation room becomes a final, chilling stage. As he confronts the detective and the questions about the night unfold, the Hat Man finally materializes in a photograph, confirming to Scott that his wife’s experiences were real.
