Karen Nichols is a recovering alcoholic haunted by unsettling visions that may be psychic in origin. After being released from a hospital, she and her husband Alan 'Al' Nichols relocate from San Diego to a quiet hillside home in Los Angeles. The move brings new faces into their life: across the street lives the chatterbox neighbor Mrs. Jacobs, and nearby tends to the yards with a steady hand Benny Benny, a developmentally-disabled landscaper. The fresh start quickly grows uneasy as Karen senses something watching from the shadows of the new house.
At a dinner with Alan’s boss and his wife, Karen is struck by visions of a severed hand in her bedroom and a cloaked figure on the staircase. The eerie sensations intensify, pushing her toward a renewed struggle with sobriety as she attends an Alcoholics Anonymous meeting, only to be haunted by the same images. A night out at a bar nearly derails her resolve, but she is halted by Larry Craig, a retired police sergeant who once investigated a brutal axe murder that shattered the home’s quiet year before. Larry shares that he himself felt strange occurrences in the house and recalls Lucy Duncan, a victim who bore a striking resemblance to Karen and who was murdered by her jealous son. Lucy’s severed head was never located, a detail that gnaws at Karen as the visions intensify and the house’s secrets seem to inch closer to daylight.
Back home, a mounting unease unsettles Karen further. She urges Alan to hear Larry’s account, yet he rebukes her suspicions, labeling Larry a possible con artist and casting doubt on the whole story. Madge, the neighbor, becomes a focal point of speculation as she implies that Larry’s presence in the neighborhood is tangled with rumors of an affair. The tension about trust and fidelity compounds the already fragile psyche of everyone in the house. Meanwhile, Lucy’s loyal cat, a constant landmark through the years, slips into a crawlspace, and a somber discovery follows: Lucy’s severed head is found beneath a crawlspace entry in a closet, underlining the brutality of the mystery that surrounds Karen and her husband.
Karen agrees to accompany Larry to a psychiatric hospital to visit Lucy’s son Edward, and that visit yields a troubling possibility: Edward may be Larry’s biological son. That night, Alan arrives home drunk, furious about losing his job, and lashes out at Karen, pressing her about where she’s been and what she knows. The couple’s fragile dynamic fractures further as Madge makes another appearance, and Karen, who has begun to drink again, finds herself grappling with the same spiraling visions that have haunted her since the move.
The following day, Larry confronts Benny in a bar, accusing him of Lucy’s murder. As Benny resists, Larry experiences a psychic premonition and races back to Karen’s house. Inside, Karen—now also under the influence—begins to share the visions once more, and the cloaked figure with an axe breaches the home. The shocking turn comes when Karen discovers Lucy’s cat murdered in the bathroom, and the intruder—unmasked in the chaos—is Madge. A tense chase ensues, and Larry arrives just in time to intervene, leading to a fatal fall as Madge plunges from a window and is gravely injured.
In the aftermath, a psychiatrist explains to Alan 'Al' Nichols and Larry that Madge’s murderous spree—targeting Lucy and attempting to kill Karen—sprang from irrational fears that her husband might be unfaithful with neighborhood women. The film closes on a stark note: Karen, confined in a straight jacket, laughs maniacally, suggesting that the line between reality and her psyche has dissolved into something unrecognizable.
