Subtitled "The Bat's Revenge", "Die Fledermaus" tells us how Dr. Falke revenged himself on his friend, Gabriel Eisenstein who, after a Fancy Dress Ball they had both attended, pushed Falke, dressed up as a bat, into a fountain and left him to make his own way home, at dawn, to the amusement of the local urchins.

ACT I

Gabriel, as a result of a minor misdemeanour, is due to spend a few days in gaol. Falke, as part of his revenge plot persuades him to go instead to a party at Prince Orlofsky's and report for prison in the morning. Unknown to Falke, Adele, a maid employed by Gabriel's wife, Rosalinda, is also planning to go to the party at the invitation of her sister, the ballet dancer, Ida. She persuades her mistress to release her that night "to visit a sick aunt". Unfortunately, after Gabriel's departure to the prison/party, Rosalinda is visited by an old flame, Alfred, who then finds himself arrested by the Prison Governor, Frank, and taken off to gaol, nobly admitting to be Rosalinda's husband.

ACT II
At Prince Orlofsky's party, the bored young millionaire is confidently assured by Falke that he has a plot to amuse him - involving Gabriel (under the pseudonym of Le Marquis de Renard), Frank (under the pseudonym of Le Chevalier Chagrin), Adele (calling herself Mademoiselle Olga) and Rosalinda (presenting herself disguised and masked as a Hungarian Countess). Urged on by Falke, Gabriel flirts with the "Countess" and loses to her the gold repeater watch he always uses to "bait" his possible conquests. But at the approach of dawn he must hastily leave for prison - as must Frank, the Prison Governor, though neither knows the other's ultimate destination! The Prince is highly amused!

ACT III
The drunken prison warder, Frosch, attempts to control his unruly prisoners and is not helped by the arrival of Frank, suffering from a frightful hangover. This isn't helped when Adele/Olga arrives with witnesses and reminds him of his promise of last night to make her his protege and send her to Drama School; she soon proves how well she can act! Gabriel is the next to arrive, as Adele is bundled out of sight, only to learn that Mr. Eisenstein is already there and has been there all night! It is, of course, Alfred, still dressed in Gabriel's dressing-gown and smoking-cap. To add to the confusion Gabriel's lawyer, Dr. Blint, first met in Act I, turns up and is promptly disrobed by Gabriel, who takes on the lawyer's identity in order to charge Rosalinda, who has just arrived too, with infidelity. However, her producing of the gold repeater watch soon makes him agree that all is best forgiven. When Falke and Orlofsky enter, and Gabriel is let off his prison sentence, it is generally agreed that "The Bat's Revenge" couldn't wish for a happier ending - sealed with His Majesty, King Champagne!