A provincial Siberian city is agitated by a chain of mysterious crimes, including the murder of a famous German traveler. The matter is under the control of the governor. They are handled by the security department and the gendarmerie. But success is still on the side of the criminal police - its chief, the experienced detective Fyodor Tartishchev, and a very young agent - Alexei Polyakov. They work harmoniously, passionately, dashingly, often risking their lives. They do not leave the slightest chance for criminals to escape punishment. Because a crime is always a crime, even if it is committed for good purposes...