Sherlock Holmes follows the trail of Jack the Ripper. The maniac has already killed several women in London, each time leaving messages at the scene of the murder for the detective. After an unsuccessful fight with an assassin, in which Watson is wounded, Holmes realizes that his opponent has fled... to the Russian Empire. Having rented a room on Pekarskaya Street from Dr. Kartsev, Holmes together with him unravels terrible crimes, despite the opposition of the local police in the person of the chief Trudny. In St. Petersburg, no one has heard of deduction - the methods of the London detective are not taken seriously. Another assistant to the detective is Sophia, a St. Petersburg woman, whose relationship grows for the Englishman into something more than a joint investigation.