Mariya Oktyabrskaya is a Soviet woman living in Tomsk, Siberia, when she receives news that her husband, a Red Army officer, has fallen in combat against the Nazis. Determined to honor his memory and his love, she sells all her possessions and donates a T-34 tank to the State, asking to be allowed to drive it. After completing rigorous training, he joins the 26th Guards Tank Brigade, where he earns the respect and admiration of his comrades for his bravery and skill. In the tank, which she calls \"The Companion in Arms\", she participates in several decisive battles on the Eastern Front, facing enemy tanks and planes, as well as the prejudices and machismo of some of her superiors. Her final destination will be the city of Smolensk, where she will receive a mortal wound that will make her a heroine of the Soviet Union.
