Maro is sentenced to prison for participating in the workers' unrest, his orphaned boy is adopted by a rich manufacturer. Years later, Maro learns that the prosecutor Mamulov, who is trying Maro's fellow revolutionaries, is his lost son. Maro asks him to lighten the sentence, but the prosecutor does not recognize the woman as his mother and throws him out of the house. At the trial, during the announcement of the death sentence, Maro will kill his son with a revolver.