The movie is based on the real life events of Ralph Sarchie, a New York cop who meets a Castilian priest when he is pulled into a case which the priest convinces him, against the officer's religious beliefs, is demonically related. Together, they work to solve the case and combat paranormal forces working against them. The two exorcise a powerful demon from a man who is now the sole survivor of a small group of marines who became possessed in a cave in Iraq. The film concludes with Ralph and his family and friends gathered for Ralph's newborn child's christening—performed by the same priest who helped Ralph. It is made known that later Ralph quits the police force and begins working with the priest against evil.