The Marschallin, a noblewoman in her early thirties, is engaging in an affair with Octavian, a boy of seventeen. She is fully aware that their relationship is doomed: he is sure to find someone closer to his age, and the Marschallin will be forgotten. The lovers are interrupted by the vulgar Baron Ochs, who has come to Vienna to marry a much younger woman, Sophie von Faninal, primarily for her father's money. He needs a young man to act as the eponymous "rose cavalier" in order to be properly engaged. The Marschallin suggests Octavian for the role.
At the nouveau riche Faninal household, Octavian's arrival as the rose cavalier is spectacular, and Sophie is overwhelmed. Left alone for a few minutes, the two young people get acquainted and discover they have good chemistry. Ochs's arrival disgusts both Octavian and Sophie, particularly as the Baron treats her as an attractive piece of meat. Incensed, Octavian challenges the Baron to a duel and wounds him slightly. The Baron howls with pain, but his spirits improve when he arranges a secret liaison with a beautiful girl, who he doesn't know is Octavian in disguise.
At a rustic inn, the Baron's attempted seduction goes poorly, as a whole host of people he has insulted and annoyed take their revenge by scaring him, pretending he is already married with a host of children, and finally exposing him as the fraud he is to his would-be father-in-law, Faninal. The Marschallin arrives, sorts everything out, dismisses the Baron, and, with sadness, encourages Octavian to go off with Sophie.
This opera provides examples of:
- Antiquated Linguistics: Hoffmannsthal's German libretto uses archaic polite forms of address, not always appropriately or correctly.
- Attractive Bent-Gender: Octavian makes such an attractive woman that Baron Ochs is willing to risk his lucrative engagement for a date with him.
- The Cameo: The tiny role of the Italian singer, who sings one very difficult song in Act 1 and never appears again, has often been sung by major singers, particularly on recordings; Luciano Pavarotti recorded the part in the 1960s and later played it onstage at the Metropolitan Opera.
- Crosscast Role: Octavian is one of the classic "trouser roles" in opera, played by a mezzo soprano (on rare occasion by a soprano). When Octavian dresses up as the Marschallin's maid "Mariandel", it's a classic case of Recursive Crossdressing.
- Faint in Shock: Faninal, when he realizes Baron Och's true character. (Possibly justified, since he's mentioned early on to be in frail health).
- Fairytale Motifs
- Humiliation Conga: The Baron loses his bride, his reputation, his money, his seduction target, his dignity, and his wig.
- I Want My Beloved to Be Happy: The Marschallin.
- Kissing Cousins: Octavian is the Marschallin's cousin.
- Matron Chaperone: Marianne, Sophie's maidservant.
- Maybe Ever After: For Sophie and Octavian, as described above.
- Mrs. Robinson: The Marschallin, though she's not supposed to be old enough to really be a mother to Octavian.
- Nouveau Riche: The Faninals.
- Upper-Class Twit: The Baron.
- When the Clock Strikes Twelve: Alluded to in the music, though due to the quirks of 18th-century clockmaking, there are thirteen strokes of the celesta and harps.
- Wig, Dress, Accent: Octavian's "Mariandel" disguise (he affects the thickest of Austrian accents)