A photojournalist specializing in erotica and investigating a case of pimps is kidnapped by people wearing gas masks. The key to solving the kidnapping is a nude photograph of a girl wearing a hat. It is taken from the back, the face is not visible, but clearly visible mole, by which you can identify the girl. True, this mark is on such a part of the body, which is usually hidden under clothes. The journalist's friends begin to investigate.