In the Soviet Union during September 1941 there was an emergency evacuation of people from Leningrad across Lake Ladoga. By a twist of fate, a young couple, cadet-gunner Kostya Gorelov and his girlfriend Nastya Tkachyova, are on board the dilapidated barge 752, the purpose of which is the evacuation of the inhabitants of the Siege of Leningrad. The barge is badly worn out, but Nikolai Gorelov, Kostya’s father, taking responsibility, ordered to load on it over 1,000 people, among them the son. Among the evacuees is NKVD investigator Vadim Petruchik, who led the case of Nastya's father.