The year is 1947. Police captain Alexander Ratnikov is investigating a series of murders in Leningrad. The trail leads to Pavel Vedernikov, a technologist at a local fish farm. It turns out that in fact, technologist Vedernikov is a former deputy head of the Nazi concentration camp for children "Grachi" named Gunther Seiler. Skillfully posing as a Soviet citizen, Zeiler hunts for his family's art collection, which disappeared during the war. The criminal is ready to walk over corpses, just to get what he wants and go beyond the cordon. Ratnikov intends to catch Seiler at any cost: this Nazi is the only clue in the story of the captain's daughter, who disappeared during the war.