Act I: The Eisensteins’ apartment
Eisenstein is about to report for an eight-day prison sentence, but encouraged by Dr. Falke, he decides to attend Prince Orlofsky’s masked ball first. Rosalinde realizes her husband’s departure means she can entertain her lover Alfred, so she gives the maid Adele the night off. Adele is delighted, since she has also been invited to Orlofsky’s party, which she plans to attend disguised as an actress. Alfred arrives; he and Rosalinde settle down to champagne, only to be interrupted by the arrival of Frank, the prison governor. Frank logically believes Alfred to be Eisenstein and Alfred plays along, allowing himself to be escorted off to prison.
Act II: Prince Orlofsky’s Masked Ball
Adele arrives at the party, pretending to be “Miss Olga,” a Russian actress. Eisenstein, claiming to be a French Marquis, is intrigued with her but puzzled as to why she looks so much like their maid. Rosalinde also arrives, having been secretly invited by Dr. Falke, and presents herself as a mysterious Hungarian Countess. She flirts with her disguised husband, who is entranced. Rosalinde manages to finagle a valuable pocket watch from him, planning to keep it as evidence of his philandering. Orlofsky leads the guests in a toast to champagne. The clock strikes six a.m., so Eisenstein rushes off to report to prison.
Act III: At the Prison
The drunken jailer Frosch tries to keep order, but is annoyed by Alfred’s constant singing. Prison governor Frank arrives from Orlofsky’s party, followed by Adele and then Eisenstein. The latter explains who he is, but Frank refuses to believe him, saying that he personally arrested Eisenstein the previous evening. Dr. Blind appears, having earlier been summoned by Alfred, and Eisenstein borrows his cloak, glasses and wig. So disguised, he begins to interrogate Alfred. They are interrupted by the arrival of more party guests, including Rosalinde, who asks “Dr. Blind” to initiate divorce proceedings against her wayward husband. Eisenstein removes his disguise and tries to shift the blame to his wife, but Rosalinde produces the incriminating watch. They finally agree that they really do love each other and everyone celebrates their reconciliation.