The way Saint Peter explains it to the Devil who's knocking on Heaven's door to collect his share of souls: there will be no more souls, as God has come to doubt if humans are really meant to achieve salvation. If they aren't then how can they be punished posthumous and sent to Hell? There's only one way to make sure if sinning is the human nature, or is it that they simply don't want to better themselves - Devil himself must go down to Earth, in human form, and if he can achieve salvation then so can a human being... Based on A. H. Tammsaare's classic novel of the same name.

Soviet spy Ladeynikov learns that in one of the pharmaceutical centers in a small resort town works a former German war criminal, Dr. Hass, who is finishing the creation of a deadly chemical gas RH development that he began during World War II, experimenting on POWs. Since Ladeynikov doesn't know Dr. Hass's appearance, Soviet intelligence recruits an actor, Ivan Savushkin, who, during the war, escaped from a prison camp where Hass was testing his gas. Together, they must identify and stop him before he finishes and unleashes his weapon of mass destruction.