While returning to England from Istanbul, famed Belgian detective Hercule Poirot finds himself traveling on the Orient Express. One of the passengers, Mr. Ratchett informs Poirot that he has been receiving anonymous threats and asks Poirot to act as his bodyguard. Poirot declines but when Ratchett is found the next morning stabbed to death, it is apparent that the threats he received were very real. Poirot soon deduces that Ratchett was in fact the infamous Cassetti, believed to have been the man behind the kidnapping and murder of 3-year old Daisy Armstrong some 5 years previously. As he begins to question the dozen or so passengers on the train, he realizes that several of them have a connection to the Armstrong family and he begins to form a solution to a very complex crime.
