When police officer Bob Hightower (Nikolaj Coster-Waldau) discovers that his ex-wife has been murdered and his daughter kidnapped by a satanic cult, he is frustrated by the authorities’ botched investigation. Bob leaves the police force and infiltrates the demonic cult to hunt down the charismatic leader Cyrus (Karl Glusman). But he will not be alone, he is helped in his mission by the only female victim who has escaped from the sect: Case Hardin (Maika Monroe). Bob is led down the rabbit hole to save his daughter, and Case takes the opportunity to reclaim her past from the cult that she has taken so much from him.