In the early post-World War II years, a cardinal (Alec Guinness) in an unnamed eastern European country is thrown in jail for treason. While there, he is subject to an intense degree of torture, both physical and psychological, by his captors. These are led by a wily man known only as the Interrogator (Jack Hawkins), who uses every tool at his disposal to get the strong-willed prisoner to issue a statement to his flock renouncing the role of religion in society.