Luba is 35 years old, and 15 of those she lived alone, raising her son Stepan. Luba works as a secretary of the village council. Her way of life is violated by the return of her longtime boyfriend Victor.

In the center of the lyrical and dramatic narrative is the frontline fate of one of the millions of ordinary soldiers of the Great Patriotic War - sapper Fedor Chaklun and his four-legged assistant - a specially trained sheepdog named Rumba. With the help of Rumba Fedor discovers a mined section of the road and warns about it senior in rank - junior lieutenant Svetlana. But the girl, carried away by flirtation with the lieutenant colonel, forgets to block the road, and a Soviet tank explodes on the mine. Fyodor, in love with Svetlana, takes the blame...