Private detective Drongo has been invited to an international political conference in the Belgian city of Bruges. He and several other high-ranking guests decide to take the train. Immediately after departure, a murder occurs in a first—class carriage, and the Turkish ambassador, one of the conference participants, is killed. It is clear that the crime was committed by one of the passengers or the conductor. But by whom exactly? Drongo immediately begins an investigation, his plans are to catch the killer before arriving in Belgium. But it's very difficult to do this, because the criminal is a professional, and he does not sit idly by waiting for exposure...