Orson Welles and Joseph Cotten co-wrote and starred in this classic espionage tale. American engineer Howard Graham (Cotten) is helping the Turkish navy to modernise their ships. His work complete, he is ready to return to the United States with his wife, Stephanie (Ruth Warrick), when a Nazi attempt on his life narrowly fails. Graham is taken to Turkish Secret Service Head Colonel Haki (Welles), who explains that the Germans are attempting to delay the modernisation of the navy. Haaki persuades Graham to travel to Batum aboard a Greek ship, promising to accompany Stephanie separately by train.