In 1953, in a communal apartment in Moscow, Luba lives with her 16-year-old son Robka. Luba's eldest son Boris is serving time for robbery, and her husband has gone missing in the war. Tired of waiting for his return, she decides to remarry. However, unexpectedly, a new tenant moves into the communal apartment - Sergeant Stepan Kharlamov, who has lost one leg - and he falls in love with Luba at first sight.