Scene 1 - the courtyard of a tenement building in the poor quarter of Madrid, on the night of the verbena. After a spirited orchestral Preludio, based on the main musical themes of the zarzuela, the curtain rises on the courtyard. We meet three couples, the tailor Cándido and Gorgonia, Tiberio and Encarnacion, Atenedoro and Soledad - and a highly attractive, provocative young woman called Mari-Pepa. Without really intending to, she has teasingly alienated the affections of the three males, who vie for her favours in reasonably friendly rivalry. Their wives, led by the outspoken Gorgonia, are not surprisingly on the warpath against this girl they call La Revoltosa ("troublemaker".) Her other admirers amongst the residents include the local officer of the Guardia, old Signor Candelas, and an unattached young man, Felipe.
Cándido, Atenedoro and Tiberio are playing cards with Felipe in the cool of the evening, delicately evoked by the orchestra. As soon as they think their wives are out of the way, Atenedoro gets out his guitar and begins a Serenade at Mari-Pepa's window (Canto y Seguidillas: "Al pie de tu ventana".) Gorgonia overhears the men and shouts at them to shut up, and the chorus take up her mockery. When Mari-Pepa herself emerges onto a balcony and throws some of the sarcasm back into the women's faces, things threaten to turn nasty. Felipe tries to calm things down, but the jibes turn into a general verbal altercation between all the men and the women generally. Candelas emerges from his room in full uniform, and breaks up the racket, ordering everyone to disperse. He pompously lectures the card-players about their marital duty, is soundly jeered at and leaves indignantly. The men continue to play, the women light the lamps outside their houses and bid each other good night.
Felipe mocks his neighbours for their obsession with a worthless, amoral cat like Mari-Pepa when they have such beautiful, intelligent and loving wives (or fiancées - Atenedoro is still only engaged to his Soledad.) They ridicule him for his failure to appreciate Mari-Pepa's stunning looks and great body. When she comes down the stairs and starts flirting with the other three, Felipe throws in his hand and leaves in sneering disgust. The men vie for Mari-Pepa's favours in a delightful Quarteto: "La pobrecilla". She teases them mercilessly, playing each one off against the others as their suggestive insinuations become more and more outrageous. After working them up into a sexual frenzy, she agrees to give them an answer "soon," and goes back inside. The women have had enough. They come back down in a fury, and try to bully their men back into line. Gorgonia pleads with Candelas to lay down the law to the destructive trollop, and he agrees to lecture Mari-Pepa, despite objections from the men. When it comes to the point, however, la Revoltosa twists the old official round her little finger, and soon has him more besotted than the rest. The other women, infuriated, give her a tongue-lashing. Mari-Pepa gives as good as she gets, until Felipe comes out to restore peace by flattering the wives at la Revoltosa's expense. She, of course, is thrown by his cool indifference. Meanwhile Gorgonia is hatching a mysterious plot with Candido's apprentice boy Chupitos, and the scene ends with the women determined to band together to defeat their dangerous rival and put the men in their place.
Scene 2 - Later that evening, outside a doughnut shop. Mari-Pepa is riled by Felipe, chatting up two young chulapas (shopgirls) over a doughnut. When they leave, she approaches him and the two of them exchange a brilliant series of studied taunts and veiled come-ons. They each describe the Lover of their Dreams, and enjoy their sparring match so much that when they separate, it is with some reluctance. The next couple to appear on the scene are less happy - Cándido has been lurking in the doughnut shop following Mari-Pepa, and he is caught sneaking out by the vigilant Gorgonia. His wheedling and her incensed fury affords a contrast to the lively wit of the younger pair, until finally Cándido is dragged back home under a rain of blows. The scene ends quietly with the distant voice of Soledad, heard singing a fragment of a street song - pertinently lamenting the treachery of man once woman as given him all - to the rhythmic clapping of the chorus (Guajira: "Eso le pasa a las hembras")
Scene 3 - back in the tenement courtyard that night. The popular Intermedio, a fast and furious orchestral dance, leads into the final scene. All the inhabitants are enjoying the evening, singing and dancing. (Coro: "¡Olé los niños con esbeltez!") Candelas is coming on to Soledad, and Chupitos is putting Gorgonia's plan into action, secretly whispering to the eager three and Candelas that Mari-Pepa will meet them privately in her room at ten o'clock. Soledad sings another two verses of her song (Guajira: "Cuando clava mi moreno") as the chorus clap and sing with her. The errant husbands and hypocritical Candelas give various excuses to hang around outside, whilst Chupitos and the three wives pretend to go into the street to join their neighbours at the verbena. Felipe appears. He can't stop thinking of Mari-Pepa, but how far he can trust such a woman? Is she really as bad as she seems? She comes in suddenly, and taken unawares they drop all reserve, and admit their true feelings in a warmly sensual - and musically sophisticated - Dúo: "Por qué de mis ojos", which moves from hesitant probing to a triumphant celebration of mutual passion. Soon, however, Felipe's jealousy reasserts itself, Mari-Pepa's pride is stung - and the two are at one another's throats again, storming off to their respective rooms.
It is nearly ten o'clock. Chupitos looks round the street door. Seeing the coast is clear, he ushers the wives back up to Soledad's apartment to enjoy the fun. (Escena: "No hay nadie, adentro".) The four Lotharios, sneaking towards Mari-Pepa's room, run up against one another in the dark, and suspiciously separate again. Felipe, despairing at the thought of losing his love, comes out in time to spy Candelas creeping back along the balcony. When the old lecher knocks on Mari-Pepa's door, Felipe goes for him, and an immense row erupts, involving a frightened Mari-Pepa, Candido, Tiberio and Atenedoro as well as their three women, Chupitos and all the neighbours, who run back in to see what the trouble's about. Before Felipe can do murder, Gorgonia explains - Mari-Pepa is innocent, the whole thing is a plot to trap their husbands and the disgraceful Guardian of the Peace. The domestic drama is done, the women look likely to forgive their men, Candelas reasserts his shredded dignity - and the two relieved young lovers bring down the curtain at the end of the sainete, with a plea to the audience to "pardon its many faults."