Christopher Plummer stars in this World War II espionage thriller directed by Terence Young. Eddie Chapman (Plummer), a safecracker, is caught and imprisoned on the island of Jersey. When German forces invade and occupy the island, he persuades them that if they set him free, he will work for them as a spy. Upon returning to Britain, he contacts the authorities and offers his services as a double agent, but who is he really working for?