Cinema Archivist David Williams lives with his wife, Alice, and their 6-year-old son. All seems well until David begins to suspect that Alice is cheating on him. His anxiety is then compounded by a bizarre coincidence at work: cataloguing a filmreel from 1902, he learns that his home was the site of a brutal series of murders by an occultist named William Jackson, who slew his wife for being unfaithful and drowned both their children in the nearby canal. As David's suspicions grow, a terrifying shadowy figure of a man starts to appear to him. One night, David follows Alice and his worst fears are realized; she is having an affair. Soon after, Alice is found drowned in the canal. David is convinced she was killed by an evil supernatural presence that inhabits his house, a presence that never ever wants him or his son to leave.