October 1981. A dead woman is found near the Motol stream. The Prague murder squad led by Jiří Marković suspects that he is dealing with a sexual deviant. Nobody knows that this is the beginning of an investigation into one of the most famous Czechoslovak serial killers.

Jiří Markovič meets Ladislav Hojer face to face for the first time. Could a screaming boy who looks like he can't count to five be responsible for murder? And how come you were so skilled at your first murder?

Ladislav Hojer gets closer and closer to investigator Jiří Marković and confesses to another murder, this time in Brno. The investigators don't believe him at first, but gruesome details gradually come to light that shock everyone.