Just after midnight, a snowstorm stops the Orient Express dead in its tracks in the middle of Yugoslavia. The luxurious train is surprisingly full for this time of year. But by morning there is one passenger less. A 'respectable American gentleman' lies dead in his compartment, stabbed a dozen times, his door locked from the inside . . . Hercule Poirot is also aboard, having arrived in the nick of time to claim a second-class compartment -- and the most astounding case of his illustrious career.