Breslau 1933: the mutilated body of a young woman and her lady's maid are found sprawled in a train, scorpians writhing in their slashed and naked stomachs. An indecipherable note in an apparently oriental language lies next to the lifeless bodies. Inspector Mock is called to head the investigation. With his young assistant, Herbert Anwaldt, he must discover the perpetrator of this most macabre of crimes.