Alfred serenades Rosalinda while Rosalinda's maid Adele wonders how she can attend Prince Orlofsky's ball. That night, Rosalinda's husband Eisenstein must begin some minor jail time. Dr Falke persuades Eisenstein to go with him to Orlofsky's party instead of jail. Eisenstein reminds the doctor of the time he left him out in the park the night after a costume party. Falke was awakened at broad daylight by a jeering crowd and had to sulk home in his bat costume. Adele is given the night off, and she attends the party. Alfred reappears at Rosalinda's home. At Falke's request, Rosalinda goes to Orlofsky's party disguised as a Hungarian Countess. Alfred is taken to jail, mistaken for Eisenstein. Falke sets his practical joke in motion. He introduces Eisenstein to Orlofsky and mentions that Adele is an actress named Olga. Rosalinda arrives wearing a mask, and Eisenstein unknowingly woos his wife. When the clock strikes six, Eisenstein hurries off to jail. He turns himself in, but the jailer believes Alfred is Eisenstein. The complications come to a climax when all gather at the jail after the party breaks up. Dr Falke tells Eisenstein that the party's events were merely his revenge.