ACT I. Vienna, 1890s. Through the windows of the Eisenstein home floats the serenade of Alfred, a tenor still in love with his old flame Rosalinde, now the wife of Gabriel von Eisenstein. Adele, a chambermaid, saunters in reading an invitation to a masked ball; Rosalinde, bedeviled by a headache and believing she has heard Alfred's voice, enters but finds only Adele. The maid asks for the evening off to visit a "sick aunt," a plea her mistress dismisses. Alfred steps into the room and begins to woo Rosalinde, who resists his verbal blandishments but melts on hearing his high A. The suitor leaves as Eisenstein and his lawyer, Blind, arrive from a session in court: Eisenstein has been sentenced to a fortnight in jail for a civil offense. No sooner does he dismiss the incompetent advocate than his friend Falke comes to invite Eisenstein to a masquerade, suggesting he bring along his repeater stop-watch, which charms all the ladies, so he can accumulate pleasant memories to sustain him during his confinement in jail. Rosalinde joins Adele in a bittersweet farewell to Eisenstein before he goes off to prison, got up, to his wife's surprise, in full evening dress. Sending Adele to her "aunt," Rosalinde receives the ardent Alfred. Their tête-à-tête is interrupted by the warden Frank, who mistakes Alfred for the man he has come to arrest. Rosalinde persuades Alfred to save her name by posing as her husband, and Frank carts him off to jail.
ACT II. In an antechamber at the palace of Prince Orlofsky, the nobleman's guests, Adele and her cousin Ida among them, await the arrival of their host. Orlofsky enters, quite bored — even with Falke's promise of a comedy of errors. The prince proclaims his guests free to do anything that suits their fancy — "Chacun à son gout." Adele, dressed in one of Rosalinde's most elegant gowns, laughs off Eisenstein's suggestion that she resembles his wife's chambermaid. Frank enters, and Rosalinde, also invited by Falke, arrives disguised as a temperamental Hungarian countess; she is soon wooed by her own reeling husband, whose pocket watch she steals to hold as proof of his philandering. Rosalinde agrees to sing a song about her "native" land, a spirited czardas, after which the guests move on to a magnificent dining area to toast the joys of wine, good fellowship and love. Champagne flows, and the guests dance wildly until dawn. When the clock strikes six, Eisenstein staggers off to keep his appointment at the jail.
ACT III. Moments later at the prison, Frosch, a drunken jailer, tries to keep order among the inmates, who are unable to sleep because of Alfred's singing. Frank arrives, still giddy with champagne, followed shortly by Ida and Adele, who, thinking him a theatrical agent, believes he might further her stage aspirations. Frank, hearing someone at the door, hides the girls in a cell and then admits Eisenstein, who has come to begin his sentence. The new prisoner is surprised to learn his cell is already occupied by a man who claims to be Eisenstein and who was found supping with Rosalinde; to obtain an explanation from the impostor, Eisenstein snatches a legal robe and wig from his astonished lawyer. No sooner is he disguised than Rosalinde hurries in to secure Alfred's release and press divorce charges against her errant husband. With her would-be paramour, she confides her flirtation to the "lawyer." Enraged, Eisenstein removes his disguise and accuses his wife of promiscuity, at which Rosalinde whips forth the watch she took from him at the ball. Orlofsky and his guests arrive to celebrate the reconciliation of Rosalinde and Eisenstein, singing a final toast as Eisenstein is taken away.
-- courtesy of Opera News