The Soviet command has alarming information about the new invention of the enemy. According to intelligence, the Nazis delivered a batch of new chemical shells filled with gas of tremendous destructive power to one of the sections of the Eastern Front. The Nazis want to test them in combat conditions, and then apply them on a large scale.

Lyuska, an employee of the only savings bank in the very young town of Radiozavodsk, wins a nylon fur coat on a lottery ticket. Her colleagues advise her to get the money and buy something useful. Lyuska goes to the regional capital, receives the money, and decides to spend it on a two-week trip to Moscow.

A finding of an old briefcase in a ruined house in 1970s leads to a treasure, hidden in the 1920s.