On Hölzle's first day of vacation in the Harz Mountains, a young woman is found beheaded. All evidence points to the husband as the murderer. However, the chief detective has doubts. He begins to investigate on his own and uncovers an incredible series of murders. For 20 years, a killer has been operating unnoticed, killing his victims using medieval methods. During his inquiries, Hölzle himself becomes the target of the murderer and finds himself in deadly danger.