The year is 1938. Dutch mystery writer Cornelius Leyden (Peter Lorre) is visiting Istanbul. A fan of his, Colonel Haki (Kurt Katch) of the Turkish police, believes Leyden would be interested in the story of Dimitrios Makropoulos (Zachary Scott), whose body was just washed up on the beach. Leyden is so fascinated by what Haki tells of the dead arch-criminal that he becomes determined to learn more.