In 1924, veteran Bolshevik Petrov, a resident of Tsaritsyn, carries a letter to Vladimir Lenin, to inform him of the Kulak brigands that roam the land, spreading death and misery. The Kulaks murder him. His widow, Varvara, continues his quest, joining a group that travels to Moscow. When they arrive, they discover that Lenin is dead. In the Kremlin, Vyacheslav Molotov tells Anastas Mikoyan that now, Grigory Zinoviev, Lev Kamenev and Nikolai Bukharin will attempt to subvert the party by attacking Stalin, Lenin's devout disciple. Stalin, mourning his teacher's passing away, carries a eulogy in the funeral, calling for all attendants and all the people of the Soviet Union to vow to maintain his legacy. The people swear. Varvara sees Stalin and hands him over the blood-stained letter entitled "To Lenin". Varvara's son, Sergei, becomes an inventor, developing the first Soviet tractor with Stalin's encouragement. Her other son, Alexander, becomes manager of the Stalingrad Tractor Factory. Stalin leads the people of the USSR in implementing the Five-Year Plans and in industrializing their country, in spite of Bukharin's resistance. American saboteurs burn the Tractor Factory, killing Varvara's daughter, Olga. As the Germans threaten world war, Sergei travels to Paris, to warn of the impending danger. The French and the British reject Soviet warnings. As the Second World War begins, the two sons volunteer for the front. At the end of the war, Varvara and Stalin meet again in the Kremlin. Stalin kisses her hand, in recognition of the Soviet mothers' contribution to victory, telling her that soon, all that Lenin has foreseen would be fulfilled.