The Princess Werdenberg has taken the opportunity of the absence of her husband the Field- Marshal to allow her lover, the young Count Octavian Rofrano, to spend the night with her. Unexpectedly early in the morning sounds outside become audible in her bedroom; she fears that this may mean the premature return of her husband, and hurriedly makes Octavian hide. It is not indeed the Field-Marshal, but Baron Ochs auf Lerchenau, to whom the “Marschallin” is distantly related. Ochs bursts in so suddenly that Octavian has not enough time to escape; hastily donning some clothes of the Marschallin’s maid, he emerges pretending to be a shy young country girl by the name of “Mariandel” who has only just taken up employment in the mansion, and is promptly harassed by the shamelessly lascivious attentions of Ochs. The latter is intending to marry the young daughter of Herr von Faninal, who is very rich and has been recently elevated to the peerage, and he has come to ask the Marschallin to suggest to him a suitable candidate to perform the traditional ceremony of presenting a silver rose to Sophie as a symbol of his betrothal to his bride-to-be. While discoursing on this he continues to make flagrant advances to the supposed “Mariandel”, much to the amusement of the Marschallin. After putting up with the Baron’s bragging about his amatory prowess, she then suggests Octavian as the “Rose-Bearer” and shows a portrait of him to Ochs, who is promptly struck by a certain resemblance to “Mariandel”. The latter is at last able to evade the lewd attentions of Ochs when it is time for the Marschallin’s “Lever”, the daily audience given to a motley throng of people offering their services or seeking her patronage (among them are her Notary and the intriguers Valzacchi and Annina). Ochs buttonholes the Notary about the formalities of his marriage, in particular with regard to the bride’s dowry and the “morning gift”, and breaks up the Lever by an angry outburst in the middle of the aria of an Italian singer. When all have dispersed and the Marschallin is alone again, she is overcome with melancholy. She senses the inexorability of Time, feeling that she can keep hold of nothing and evade nothing. Octavian, who has now been able to discard the maid’s clothing, fails to comfort her: on the contrary, she knows that sooner or later Octavian will find someone younger and desert her. When he tries to protest, she sends him away curtly and omits to give him the silver rose which he is to present to the Baron’s bride, so she sends her little page to bring it to him.
Faninal takes leave of his daughter, because tradition will have it that she must be alone when the Rose-Bearer comes. Her Duenna, Marianne Leitmetzer, gives her an excited commentary on the latter’s arrival. The solemn ceremony of the Presentation of the Rose becomes the birth of the love between Octavian and Sophie. Making conversation afterwards, they find their way to each other. Then follows the arrival of her bridegroom-to-be, whose boorish behaviour and clumsy amatory advances horrify Sophie. Despite her resistance, the enraged Octavian is obliged to witness how Ochs gives her a foretaste of the marital liberties he looks forward to taking with her. The moment he leaves to sign the marriage licence next door, Sophie and Octavian come together in the knowledge that they were destined for each other, and they declare their mutual love. The intriguers Valzacchi and Annina surprise them and seek the favour of Ochs by calling him to witness the scene. Ochs is not the man to make a fuss about the incident, but when he tries to drag Sophie into the next room to sign the marriage contract, Octavian draws his sword and slightly wounds him, causing a general uproar. Faninal is outraged by the scandalous situation, threatening to shut Sophie up in a nunnery if she refuses to marry Ochs. After realizing that his wound is not mortal, Ochs is inclined to cheer up, especially when Annina brings him a billet-doux from “that certain Mariandel”. Octavian thought up this stratagem, securing Annina’s services for himself so that she can entice Ochs to agree on a rendezvous with the supposed lady’s maid.
With the help of Annina and Valzacchi, Octavian has prepared a consummate net to catch the Baron, all is ready for the rendezvous of Ochs with “Mariandel”, alias Octavian. The latter plays the coquettish maid so well that the Baron does not notice how the trap perilously closes in on him. Children claiming him as their father and all sorts of sinister apparitions, which pop up and disappear again, entirely unnerve Ochs into thinking the place must be haunted. He calls the police, but this only makes his situation worse, because the Commissioner, who soon appears, assumes automatically that the Baron has been attempting to debauch an honest girl, and holds him for stern questioning. Under pressure Ochs can only maintain that the supposed victim of his lust is in point of fact his fiancée Sophie von Faninal. Octavian has pre-arranged the arrival of the unsuspecting Faninal, who, outraged to the point of a heart-attack by the behaviour of his prospective son-in-law, promptly produces his genuine daughter Sophie, waiting in the carriage outside. Informed by the Baron’s servants, the Marschallin appears. Recognizing what is going on, she reassures the police officer that it is merely a farce, a typically Viennese prank. With equal decision she makes clear to the Baron that he has lost the game and must forget his aspirations to marry Sophie. With a derisive mob in pursuit, Ochs flees. Octavian remains, torn helplessly between the Marschallin and Sophie. The Marschallin makes his decision for him by stepping back and uniting the two young people.