 In 1949, in Cairo, Egypt, the archaeologist and former priest Merrin (Stellan Skarsgård) has a meeting with Semelier (Ben Cross), the representative of a millionaire that is interested in an antique piece hidden in a circa 5 A.D. buried Christian church discovered in East of Africa in a British colony. Merrin lost the faith in God in the WWII, when he was obliged to select ten victims for a Nazi officer, and accepts the work. Together with the Catholic Father Francis (James D Arcy), assigned by the Vatican to investigate how a church could be mysteriously built in a place 1,500 years before the records of the first church in the area, they travel to the spot with the authorization of the British command. They meet with Dr. Sarah (Izabella Scorupco), a woman that was brutalized by the Nazis in the war that is responsible for the local hospital, and while investigating, they realized that the church was built to protect the area against an evil force, which has been released along the excavations. Father Merrin has to return to his path of "Man of God" to fight against evil.