Place: Warsaw, Poland, and a village in the Polish countryside Time: early 19th century

Act I
Warsaw. A great ball is to be held at the house of the recently widowed young Countess in a couple of days. Everyone here is busy with the preparations and talking about the greatness of the projected event. A breathtaking Diana's costume (dress) is being sewn for the Countess. Dzidzi is doing his best to win the Countess's favour. Also present in the household is Bronia, the Countess's distant relative who is being courted by the elderly Podczaszyc. Bronia has recently come to town from the country and she is feeling miserable in the new surroundings. She complains to her grandfather (the Chorąży) that she does not feel at home in the artificial world of the salon, a fake world full of unnatural foreign customs and empty laughter (O mój dziaduniu arietta). Bronia is unhappily in love with a neighbour from the countryside, the young nobleman Kazimierz who is also present in this house. He in turn loves the Countess. He is told by Chorąży to stop moping and go for a hunt (Ruszaj bracie, ruszaj w pole song). Kazimierz, however, feels that his happiness depends on the Countess's returning his love (Od twojej woli aria).

Act II
Before the ball the Countess puts on her new dress and admires herself in the mirror (Suknio coś mnie tak ubrała aria). The guests assembled in the ballroom are clearly divided into 2 groups: Kazimierz, Bronia and Chorąży form the "national side" - dressed in simple, traditional Polish attire. The other guests form the "foreign side" - luxuriously dressed yet alien to Polish tradition. We next witness a rehearsal of the show which is to aggrandize the ball: first a ballet scene (ballet music), then a virtuoso aria sung by the Countess's friend Ewa (Italian aria), then the Podczaszyc dressed up as Neptune arrives in a shell-shaped chariot, greeted by the other guests. The final number was to be sung by another of the Countess's friends, who fell ill. Bronia fills in for her and sings a sad song about a peasant girl longing for her soldier lover who went to war - she promises to be faithful to him to the grave (Szemrze strumyk pod jaworem song). The foreign-type guests are unmoved and find the song too trivial. Kazimierz, Chorąży, and even Podczaszyc are extremely impressed by the song's simple, sincere beauty. Madame de Vauban, the most prominent of the guests, arrives. In the ensuing disorder Kazimierz accidentally steps on the Countess's dress and tears it badly. Her polite attitude is immediately gone. It is clear that Kazimierz has lost all favour with her.

Act III
The Chorąży's country manor. A melancholy polonaise melody played by four cellos evokes the serene and patriotic atmosphere of this house. The Podczaszyc, who is a guest in this house, is out hunting (Pojedziemy na łów - Hunters' song). Bronia misses Kazimierz who after the unfortunate incident at the ball has set off to war. Unexpectedly, the Countess arrives - she has understood the value of Kazimierz's true feelings, and, having learned of his upcoming arrival and expecting that he will stop by Chorąży's house, she is eager to greet him and regain his love (On tu przybywa aria). Upon seeing Chorąży's country manor Kazimierz is reminded of Bronia's sweet face and sincerity (Rodzinna wioska już się uśmiecha aria). He greets the Countess rather coldly. Neither Bronia nor the Chorąży are aware of Kazimierz's change of heart, and they are anxious about his and the Countess's arrival at the same time. The Podczaszyc has however understood everything, including the inappropriate age difference between him and Bronia. A little drunk, he gives a long speech and proposes to Bronia on Kazimierz's behalf. Kazimierz kneels down before the Chorąży, confirming that the Podczaszyc has indeed correctly expressed his wish. The Countess is of course deeply disappointed. Vain and proud, she does not want to show her true feelings to everyone, and decides quickly to leave (Zbudzić się z ułudnych snów aria). Dzidzi is full of new hope. The remaining guests raise a toast to the new couple.