The Belgian detective Hercule Poirot boards the Orient Express. One of the passengers requests his protection, but Poirot declines. The next day the passenger is found dead in his compartment and Poirot is asked to solve the case. The train is forced to stop due to a snow drift blocking the tracks. This gives him a few hours to figure out the murderer's identity before the local police take over the investigation. During his investigation, Poirot discovers that many of the passengers have some connection to a 5 year old case where an infant was kidnapped and murdered in which the mastermind escaped prosecution. This lead to the death (during childbirth) of the mother and the suicide of her father. This could be the vital clue to crack the case, but can he do it in time?