James Findlay (Euan Douglas) is an ordinary schoolteacher who has been estranged from his mother for years and returns to her home to settle her estate with the Solicitor (Alan Ireby). This unsettles his friend Allen Milton (Jamie Scott Gordon), who is facing his own family crisis as his father, Michael Milton, battles a serious illness. James discovers via letters that he stands to inherit two houses: a small, unassuming one and a sprawling mansion that his mother had warned him never to revisit. He ignores the warning, moves into the mansion, and tries to make sense of everything, even though his earliest memories are faint and he cannot recall his childhood clearly.
Inside the mansion, James meets the beautiful American Eve Turner (Alexandra Nicole Hulme), who lives nearby in a renovated set of stables. He also uncovers evidence of a childhood mental breakdown sparked by visions of a creature called the Owl Man (David Schofield).
As days pass, James finds himself drawn to Eve and to the eerie house that sits atop a labyrinth of catacombs. He learns that his parents once dabbled in pagan magic to gain fortune, and that their schemes were tied to the worship of Moloch, a being who would grant wishes in exchange for sacrifice. The Owl Man turns out to be Moloch in disguise, and James gradually realizes that he himself was meant to be the sacrifice.
His parents were reluctant to offer James, so they took in an orphaned American girl as a nanny and murdered her in James's place. James pieces this together, and the shocking revelation is that the girl was Eve, which unlocks her buried memories and shatters any remaining innocence as she becomes a menacing force bent on driving James mad with a series of attacks.
Desperate to escape, James tries to flee the mansion, but Moloch will not let him leave. The demon makes it clear that its anger is aimed at his parents, not James, yet the price of escape is the truth: only by finding Eve's bones and laying them to rest in the front yard can the haunting end. James locates the remains and returns them to rest, freeing Eve's soul, who departs with a broken, heartbroken farewell as James pleads with her not to go.
Back in the world of the living, James recounts the nightmare to his friend Allen, only to learn that the price has a different cost: Allen admits that Moloch appeared to him and offered to save his own father if James were sacrificed. In a fatal confrontation, Allen poisons James to carry out the ritual. The film closes with Allen driving his father home from the hospital, a haunted look on his face, and returning to the mansion where a new skull rests in the catacombs—a chilling hint that James's ghost has taken Eve's place, waiting for another sacrificial rite to begin.
