Die Fledermaus by Johann Strauss

It is New Year’s Eve in Vienna, the setting for a whirl of tricks, plot twists, deceptions, assumed identities and lots and lots of drinking!
Rosalinde von Eisenstein agrees to meet her former flame, Alfred, later that night, having been persuaded by his serenading. Her husband is about to be arrested but is convinced by a supposed friend, Dr Falke, to attend Prince Orlofsky’s ball instead. He pretends he is heading to the jail, but his ruse is revealed to Rosalinde by Falke, who persuades her to come to the ball (in disguise!) to catch her husband out in his flirtations. Angry at this deception, she gives her maid, Adele, the night off so she can be with Alfred. The prison warden, Frank, arrives to arrest Eisenstein. To protect Rosalinde’s reputation, Alfred pretends he is her husband and so is taken away.
Prince Orlofsky’s ball is in full swing. Adele arrives – she thinks her sister, a dancer, has invited her, but the invitation was from Falke, plotting his revenge on Eisenstein, who once humiliated him (dressed as a bat!) in a practical joke. She pretends to be a Russian actress to hide her humble position as a maid. Eisenstein, pretending to be French, flirts with Adele. The prison warden, Frank, also appears, likewise pretending to be French. He is taken with Adele and her sister, claiming to be a theatre impresario in order to impress them. Rosalinde, in the guise of a Hungarian countess, arrives. The “Frenchman” (Eisenstein) is smitten with her. During their flirtation she steals his watch.
At midnight, the guests toast the new year and party till dawn, when Eisenstein rushes off to the jail. He is confused to find he is already imprisoned. Frank also turns up for work, still tipsy and elated by his evening as an “impresario”. Eisenstein’s lawyer has been summoned by Alfred. Eisenstein disguises himself as the lawyer to find out what is going on. Rosalinde arrives and begs the “lawyer” to free Alfred and help her divorce her husband for infidelity. When Eisenstein reveals himself and reproaches Rosalinde for her behaviour, she produces “the Frenchman’s” watch as evidence of his betrayal. They both realise they are still in love, to the annoyance of Falke who has come to the jail to witness the ruin of Eisenstein’s happiness through his scheming.
Orlofsky and his guests then turn up. They are highly amused by the whole story and sing to the joys of champagne.