Detective Ivan Podushkin, against his will, is drawn into a very tangled case. His office is visited by the daughter and assistant of the famous magician Heinrich Dönelly. Svetlana is terrified: a voice in her head demands that she throw herself out of a window. Worrying and frightened, the girl tells how one night a bearded man entered her bedroom and gave her an injection behind the ear. Ever since then, the voice has been following her. Ivan decides she is simply crazy and refuses to help. Svetа leaves, leaving the fee in the hallway. A few minutes later, the girl throws herself out of the window of the neighboring house. When the private detective comes down to the street, the police have already arrived. During the difficult and dangerous investigation, Ivan Podushkin and investigator Varvara Kosova have to realize that this mysterious case was not without… tricks.