The story took place in 1990, when an American auto mechanic, John Gray (David Dencik), was arrested on suspicion of molesting his daughter Angela (Emma Watson). Bruce Kenner (Ethan Hawke), the police officer in charge of investigating the case, questioned John, and during this process John first admitted the crime and then suddenly lost his memory. In response to this sudden situation, psychology professor Dr. Kenneth Reines (David Thewlis) also intervened in the investigation. They found that John believed in a black religion that worshipped the devil Satan, and even Bruce's partner might be involved. Bruce and Kenneth tried every means to open the memory gates of suspects and victims, reminding them of the most unbearable past... This film is adapted from real events.