In 1930, a horrific kidnapping and murder case occurred in New York, and the mastermind Cassetti escaped with the ransom. Five years later, detective Hercule Polo (Albert Finney) crossed the Bosphorus by boat and boarded the Orient Express to London under the arrangement of his friend Bianchi (Martin Balsam). One morning, Polo was awakened by the shouting of the next-door No. 10 compartment. Later, the train was forced to stop in Yugoslavia because the snow buried the rails. Not long after Polo fell asleep again, he was awakened by the noise again. The lady Harriet Belinda Hubbard (Lauren Bacall) claimed that the rich man Ratchett (Richard Widmark) in the No. 10 compartment had sneaked into her No. 11 compartment. After dawn, Ratchett's butler Beddoes (John Gielgud) brought drinks, but couldn't knock on the door of No. 10 compartment. The conductor Pierre Paul Michel (Jean-Pierre Cassel) unlocked the door with his key, but the door chain was on the inside. Polo and Pierre worked together to open the door and found Ratchet bleeding from his mouth and dying with his eyes open. Doctor Constantine (George Koulouris) examined Ratchet and found that he had been drugged and stabbed 12 times. The time of death was between 0 and 2 o'clock...