After being discharged from a mental health institution in Québec, Alice Jarett embarks on a new chapter of her life by moving with her husband Martin to a rural part of Canada. The couple settles into a house that is far from complete, leading Martin to enlist the help of an inexpensive construction crew to finish the job. However, the tranquility of their new home is disrupted when Alice is awoken one night by the sound of hammering coming from the basement. To her surprise, she encounters a carpenter whose presence had previously gone unnoticed; he is unlike the other workers — he possesses a disarmingly pleasant demeanor and a commendable work ethic.
As events unfold, the situation takes a dark turn. One night, while Martin is away, this mysterious carpenter intervenes and saves Alice from an attempted assault by another worker, violently dispatching him with a circular saw. Shaken yet intrigued, Alice finds herself increasingly drawn to this enigmatic figure.
As she continues to interact with the carpenter, she comes to believe that he is the spirit of Edward, the original builder of the house, who met a grisly end after being executed for the violent acts he committed due to his obsession with creating a perfect home. Despite Edward's sinister history, Alice becomes captivated by his otherworldly charm, even as she witnesses him eliminate two disgruntled former workers who had the audacity to break in with ill intentions.
The tension escalates when Laura Bell, one of Martin's students, confronts Alice and reveals a shocking affair — she is pregnant with Martin's child. This revelation ignites a fierce argument, culminating in Alice, with Edward's sinister encouragement, using a nail gun to kill Laura. When Martin discovers the gruesome scene, he turns on Alice in a fit of rage, only to be overpowered and gruesomely dispatched by Edward, who crushes Martin’s head in a vise.
The horror does not cease there. Later, Alice's sister Rachel arrives, intending to take Alice away upon seeing the brutal aftermath, but she is intercepted by Edward, who reacts violently. In an unexpected twist, Alice finds herself at odds with Edward once she realizes that causing damage to the house itself is the key to stopping him. In a desperate move, she ignites a fire with a blow torch, letting the flames consume the house. As chaos ensues, Alice and a reinvigorated Rachel make their escape, briefly pursued by the malevolent spirit of Edward, who ultimately succumbs to the destructive inferno that engulfs his abode.
This chilling tale intertwines themes of obsession, retribution, and the struggle for liberation, leaving viewers on the edge of their seats as Alice navigates this harrowing ordeal filled with supernatural elements and palpable suspense.
