Just after midnight, a snowdrift stopped the Orient Express in its tracks. The luxurious train was surprisingly full for the time of the year. But by the morning there was one passenger fewer. An American lay dead in his compartment, stabbed a dozen times, his door locked from the inside.
The first message sent to Tom Thorne's phone was just a picture - the blurred image of a man's face, but Thorne had seen enough dead bodies to know that the man was no longer alive. But who was he? Who sent the photograph? And why? While the technical experts attempt to trace the sender, Thorne searches the bulletins for a reported death that matches the photograph. Then another picture arrives.