The Inexplicable Research Institute received a new appeal. Vojtech Dvorak personally went to Moscow to talk with a client. Nikolai Alexandrovich Mamontov, an influential and wealthy person, demanded to investigate the mysterious murders in the Moscow region. A certain closed boarding school for the offspring of wealthy parents has become a place of terrible hunting. Two students were killed. According to Mamontov, there will be a third victim. The client is concerned because, firstly, his son goes to this school, and secondly, thirty years ago this has already happened - three girls died. Then Nikolai Alexandrovich himself studied at this institution, and one of the stabbed was his own sister.