The city is in panic: a mysterious blackmailer-murderer sends threatening letters to the families of teenage girls. If he is not paid a certain amount on time, the letter says, the girl will be raped and killed. And these are not empty threats: the woman paid the blackmailer the required amount, however, her daughter was still killed. The inconsolable mother turned for help to private detective Tatyana Ivanova, who from the very first steps of the investigation concluded: the actions of the criminal were completely unpredictable and illogical. This means only one thing - either a madman works here, or... someone who is trying to pass himself off as such...