ACT I. The courtesan Violetta Valéry has been out most of the night running from party to party with a group of friends, who are now continuing the festivities in her Paris apartment. Flora Bervoix, the Marquis d’Obigny, Gastone, and Violetta’s patron the Baron Douphol are among the revelers, as is a new admirer of Violetta’s, Alfredo Germont. Having long adored her from afar, Alfredo now flirts with Violetta in a rousing drinking song (Brindisi: “Libiamo”). As the guests move to another room of the house to hear an orchestra play, Violetta suffers a fainting spell. Quickly regaining her composure, she assures her friends that all she needs are a few minutes alone. Concerned, Alfredo returns and confesses his love (“Un dì felice”). Violetta makes light of his declaration – she seeks pleasure, not love. But he persists, and she agrees to meet him the next day. After the guests depart, Violetta ruminates on her new suitor (“Ah, fors’è lui”), wondering if Alfredo could be the man to change her life. But she quickly opts instead for continued freedom (“Sempre libera”), as Alfredo’s voice, heard outside, sings of the pleasures of romance.
ACT II. Scene 1. For three months Alfredo and Violetta have been living blissfully in a country house near Paris. Alfredo reflects on their contentment (“De’ miei bollenti spiriti”). When their servant Annina reveals that Violetta has sold her possessions to keep the house, Alfredo hurries off to the city to settle matters at his own cost. Violetta enters and receives an invitation from Flora to a party that evening. She is soon surprised by the arrival of Alfredo’s father, Giorgio Germont, who demands that Violetta break off her affair with his son; the scandal of their relationship has threatened Germont’s daughter’s engagement (“Pura siccome un angelo”). Violetta says that she cannot, but she eventually gives in (“Dite alla giovine”). Alone, the desolate woman sends a message of acceptance to Flora and starts writing a farewell note to Alfredo. He enters suddenly, and she can barely control herself as she reminds him of how deeply she loves him (“Amami, Alfredo”) before rushing out. A servant brings Violetta’s note to Alfredo as Germont returns to console his son and remind him of his loving family back home in Provence (“Di Provenza”). But Alfredo, catching sight of Flora’s invitation, suspects Violetta has left him for another lover. Furious, he resolves to confront her at the party.
Scene 2. At her “Spanish soirée” that evening, Flora learns from the Marquis that Violetta and Alfredo have separated, then clears the floor for hired entertainers—a band of fortune-telling gypsies and matadors (“E Piquillo un bel gagliardo”). Before long, Alfredo strides in, making bitter comments about love and gambling recklessly at cards. Violetta arrives with Baron Douphol, who challenges Alfredo to a game and loses a small fortune to him. The crowd moves to another room for supper. Violetta has asked to speak with Alfredo privately. Fearful of the baron’s anger, she wants Alfredo to leave, but he misunderstands her apprehension and demands that she admit she loves Douphol. Hurt by the accusation, she says that she does. Alfredo calls in the others, denounces his former love, and cruelly hurls his winnings at her feet (“Questa donna conoscete?’’). Violetta is distraught. Germont arrives in time to witness his son’s rash act and denounces his behavior. The guests rebuke Alfredo, and Douphol challenges him to a duel.
ACT III. In Violetta’s bedroom six months later, Dr. Grenvil tells Annina that her mistress does not have long to live: she will soon die of tuberculosis. Alone, Violetta re-reads a letter from Germont saying the Baron was only wounded in his duel with Alfredo, who knows everything and is on his way to beg her pardon. But Violetta senses it is too late (“Addio, del passato”). In a feverish daze, she hears street revelers celebrating Mardi Gras and believes them to be her old friends. As she rushes downstairs to join them, Annina stops her, announcing that Alfredo has arrived. Ecstatically, the lovers plan to leave Paris forever (“Parigi, o cara”). Germont enters with the doctor, but Violetta says she feels her strength miraculously returning. But this surge of vitality lasts just a moment; she suddenly staggers and falls dead at her lover’s feet.