Just after midnight, the famous Orient Express is stopped in its tacks by a snowdrift. By morning, the millionaire Simon Ratchett lies dead in his compartment, stabbed a dozen times, his door locked from the inside. One of his fellow passengers must be the murderer. Isolated by the storm and with a killer in their midst, detective Hercule Poirot must find the killer amongst a dozen of the dead man's enemies, before the murderer decides to strike again...