Steyr, in the year of our Lord 1388. A series of gruesome murders, recalcitrant heretics, and the fanatical inquisitor Petrus Zwicker plunge the city into fear and terror. Members of the Waldensian movement are hunted and tortured as heretics, and bonfires blaze. Amidst this pitch-black chaos, an intrepid pair investigates: Falk von Falkenstein and his wife Christine. However, Falk, who harbors a terrible secret himself, soon finds himself in the crosshairs of the inquisitor, putting him in deadly danger.