The main action of this intellectual thriller, which served as the basis for the popular film, takes place in 1933. In the saloon carriage of a Berlin express, seventeen-year-old Baroness von der Malten and her governess are found brutally murdered, while the cabin is swarming with scorpions, and on the wall there is an inscription written in blood in an incomprehensible font (as the examination shows, in Old Syriac). The investigation of this ritual murder faces the most unexpected difficulties - criminal, political and occult...