The man from the house opposite

A young girl Anna lives in the countryside, in her parents' house, alone: her mother died a long time ago; her father was killed a year ago. Once a month, someone sends her money, and Anna suspects that this person is related to the murder. And in St. Petersburg, it seems that the maniac who murdered passers-by in the arches a year ago is waking up again. Soon, private detectives Makar Ilyushin and Sergey Babkin take up this case: they are addressed by the sister of Nikita Safonov, who recently disappeared. She claims that the young man who was recently killed by a maniac is one of Nikita's institute friends. And lately it seemed to Nikita that someone was watching him from the opposite house. This is Anna's house.