The Gaol Scene opens with a cameo comic sketch. Frosch, the drunken deputy warder, is suffering from a surfeit of drink and Alfred's singing in the cells. Frank comes reeling in and falls asleep. Adèle and her sister arrive at the door. They have taken up Frank on his invitation to come and live with him in his 'big town house'- an offer made while the 'Chevalier Chagrin' was not quite himself. Adèle promptly launches into The Audition Song.
No time for applause before the bell rings again. Eisenstein is at the door, reporting for his sentence. Frank refuses to believe Eisenstein is Eisenstein. After all, he arrested Eisenstein the night before, while the prisoner was in his dressing gown, having supper with his wife. Eisenstein demands to see this prisoner, but nobody is allowed into the cells. Fortuitously, his lawyer, Blind, arrives at that very moment. Eisenstein demands the lawyer's hat, glasses, cape, briefcase and beard (!), and dresses up as Blind. Alfred is brought out to consult with his lawyer. He encounters the

Act 3, In the prison offices of Governor Falke
latest arrival: Rosalinde is in a state of great agitation, partly because of her husband's behaviour at the ball and partly because discovery of her supper with Alfred is inevitable.
Alfred explains to his 'lawyer' that he has been wrongfully arrested and how it came about. Rosalinde explains how unfortunate it might seem if anyone were to find out about the innocent little supper. They find their lawyer surprisingly hostile. Eisenstein takes off his disguise and confronts them as a wronged husband. But nobody is penitent. Rosalinde dangles the chiming watch under her husband's nose.
The entire Orlofsky retinue pour in and bring an end to the confusion. Falke has brought the Count and his party-goers to the prison to conclude 'The Revenge of the Bat'. He explains that every disguise, every pseudonym, every compromising situation was part of his revenge on the man who left him on a park bench dressed as a bat. Rosalinde blames her husband's excesses on Champagne the Great, and Orlofsky decides to sponsor Adèle in her acting career.
There is a perfect excuse for everyone to break into the Champagne Song - and laughing out loud, Orlofsky pins a medal on Doctor Falke's chest.