Petrograd, 1920. A crime wave is sweeping the cradle of the revolution. Bandits, posing as security officers, rob the people - this is called “self-inflicted”. Vanka-Belka's gang has been keeping the whole city in fear for a long time. In conditions when human life is not worth a penny, criminal investigation officers are doing their best to contain the onslaught of criminals. Bogdan Peretrusov, embedded in the St. Petersburg criminal community, is investigating the mysterious murder of a leading criminal agent. The death of the latter is closely connected with the robbery of the Hermitage and a mysterious artifact - Triton, which once belonged to John of Kronstadt himself.