The film begins with a sequence (supplemented by subsequent flashbacks) in which Mikhail Kalashnikov, a young farmer's son from Altai, is seen secretly working on a functional toy rifle. The film switches to the year 1941, in the midst of World War II, where the now adult senior sergeant Kalashnikov serves as a tank commander in the Red Army. During the Battle of Bryansk, Kalashnikov is seriously wounded while taking out a German anti-tank gun, and he is taken off the frontlines. While being transported to the rear, he and a companion encounter a group of German soldiers, and he witnesses his comrade's new submachine gun failing at a critical moment due to design faults in the magazine. This inspires him to use his self-acquired talent at inventing to design a new automatic weapon for the Soviet army.