The autumn of 1941. Leningrad is besieged by the Nazis. A new model of tank is being developed at a large defense plant. Built in the shortest possible time combat vehicles are tested directly on battlefields, fighting with fascists in the outskirts of the city. The first feature film about the heroic everyday life of city defenders was shot directly in assembly shops of plants and in the streets of Leningrad when the city was fighting against the enemy