Act I
The Feldmarschallin’s bedroom.

While her husband is away on duty, Princess von Werdenberg, known as the Feldmarschallin, has been having an affair with the seventeen-year-old Count Octavian, known as Quinquin, with whom she has just spent a night of love. This is evoked by the animated orchestral prelude. In the morning the lovers exchange tender embraces, but when the Marschallin’s black page knocks to bring in her breakfast, Octavian hides. The pair then have breakfast together, but their amorous conversation is again interrupted by the arrival of Baron Ochs, the Marschallin’s cousin. Again Octavian hides, and this time reappears dressed as a seductive chambermaid, “Mariandel”, who immediately attracts the attention of the lascivious Baron. The purpose of Ochs’ visit had been to ask his cousin for advice on how to conduct the ceremony of his own engagement. For the Baron wishes to marry Sophie von Faninal, the daughter of a wealthy and recently ennobled merchant. Ochs is looking for a young nobleman to deliver the customary silver rose to Sophie, as a symbol of his request for her hand in marriage. Irritated and embarrassed by the Baron’s advances to “Mariandel”, whom Ochs invites to have supper with him, the Princess suggests Count Octavian as “the knight of the rose”. Meanwhile the butler enters to announce the visitors at the Princess’s levee.

They are a noble widow and her three orphan daughters, a hairdresser, miscellaneous tradespeople, a man of letters, a flautist and a tenor (who launches into an aria in the Italian style). They all offer their services to the Princess. Next come the Italian intriguers Valzacchi and Annina, who manage to get themselves hired by the Baron as spies.
Alone at last with Octavian, who has discarded his female attire, the Marschallin turns melancholy. She knows that her beauty will soon fade and Octavian will surely then look for a younger woman, but the Count reassures her in a conventionally hurt tone and goes out.After a moment the Marschallin realizes she has said goodbye to her lover without so much as a kiss. She sends out her servants to search for him, but too late. So she entrusts her black page with the rose to be delivered to the young knight.

Act II
A hall in von Faninal’s palace.

At Faninal’s house preparations are in full swing for the ceremony to celebrate the engagement of Sophie to Baron Ochs. The Baron is to be preceded by the “knight of the rose”, whose arrival is in fact soon announced. The two young people are irresistibly attracted to one another at first sight and Octavian, while waiting for the Baron to arrive, innocently confides his deep admiration to Sophie. When the Baron enters, he addresses his future bride somewhat rudely and Sophie is appalled by the vulgarity of her noble fiancé. While Ochs goes into the next room with the notary to draw up the marriage contract, Octavian promises Sophie that he will do his utmost to prevent the marriage. They exchange a kiss.

Valzacchi and Annina, who have entered by stealth, seize the lovers and loudly call Ochs who feigns indifference — at least until Octavian publicly announces that Sophie no longer accepts the Baron’s proposal of marriage. When Ochs orders the servants to intervene, because Sophie has taken shelter behind Octavian and refuses to sign the marriage contract, the knight draws his sword and lightly scratches his adversary. Ochs makes a tremendous scene and pretends to be dying but his servants help him to a chair. Faninal orders his daughter to change her mind on pain of being dispatched forthwith to a convent. In the meantime Annina delivers to Ochs a note from “Mariandel”, in which the maid accepts the Baron’s invitation to supper. The scene ends with Ochs feeling satisfied despite the turn of events, since he can now console himself with the thought of his imminent rendezvous.

A private room at an inn.

At the inn all is ready for the trap which has been laid in every smallest detail by the two Italians Annina and Valzacchi (who have in the meantime switched their allegiance from the stingy Baron Ochs to the more generous Octavian). When the Baron enters on the arm of Octavian, once again disguised as “Mariandel”, he is greeted by musicians who strike up a waltz, and by the staff of the inn offering their expensive services. The Baron promises a handsome tip to Valzacchi if he can arrange for a discount on the bill. During their intimate supper, “Mariandel” teases Ochs in a frivolously bashful manner and, though puzzled by the maid’s likeness to Octavian, the Baron continues to court the maid and to entice her into the adjoining bedroom. But then, all of a sudden the most terrifying, ghost-like faces begin to stare at him from every corner of the room. Annina also now enters, declaring that Ochs is her husband, while four children, instigated by Valzacchi, run up to him crying “Papa!”. The Baron is scared out of his wits and in exasperation summons the police. When the commissary arrives, Ochs claims that the young girl with him is his fiancée. But just as he pronounces her name, Faninal enters and, on seeing the situation, faints with shame.He is carried into the next room.

Sophie, who has appeared in the meantime, helps him. “Mariandel” takes advantage of this confusion to explain to the commissary the hoax enacted at his request and also to change out of his woman’s clothing. Ochs’ indignation explodes in all its fury, but he is interrupted by the arrival of the Princess. Taking in the situation at a glance, she at first dismisses the commissary, confirming to him that it really was a hoax. She then severely reprimands the Baron, who escapes, pursued by musicians and waiters demanding payment for their services. Left on stage are only Sophie, Octavian and the Feldmarschallin, who has understood by now the nature of the bond between the young couple. Though inwardly sad, she reluctantly accepts their love and goes off to speak with Faninal. After a while she comes back with him on her arm. For Sophie’s father has given his blessing to his daughter’s new fiancé. The young pair repeat their tender expressions of love and leave the inn. On the empty stage briefly appears the Feldmarschallin’s black page, who has come to look for a handkerchief dropped there by Sophie.