Act I: A salon in Violetta’s house in Paris, around August 1850.
Welcoming her guests to a party, Violetta remarks that pleasure is a drug that makes life bearable. Among the arrivals are Baron Douphol, Violetta’s current lover, who keeps her; Flora Bervoix, a friend of Violetta’s; and Gastone, a young man-about-town. Gastone introduces Alfredo Germont, who has admired Violetta from a distance. To make the tongue-tied young man feel at home, Violetta pours wine, and he responds by proposing a toast (brindisi: Libiamo ne’ lieti calici), in which Violetta and the others join. It is evident from his verses that Alfedo takes love more seriously than Violetta. A dance orchestra strikes up in the next room, and the guests start for the door, but Violetta feels faint and stays behind. Everyone leaves except Alfredo, who tells her he is deeply concerned. She cuts off his declaration (Un difelice, eterea) with frank advice: romance is not for her, and he should look for someone else. When he starts to leave, she hands him a camelia and asks him to visit her when it has wilted—the next day. Overjoyed, he kisses her hand and goes. The other guests return, saying daybreak is near and thanking their hostess. When they have gone, Violetta questions herself about the strange feelings aroused by Alfredo (A’h, fors’è lui): does she dare allow herself a serious affair? After pondering the idea, she rejects it (Sempre Libera) declaring that the giddy whirl must continue—even though Alfredo, outside repeats his words of love.
ACT II: A country house near Paris, the following January.
In the five months that have elapsed since the time of Act I, Violetta has gone to live with Alfredo outside the city. Alfredo enters the drawing room and rhapsodizes about his happiness (De’ miei bollenti spiriti). When Annina, Violetta’s maid, returns from a trip to Paris, Alfredo learns that her mission was to sell her mistress’ belongings: life in the country is expensive. The young man resolves to get money of his own to set the situation right (Oh mio rimorso!). He has no sooner left than Violetta appears, asking Annina where he went. The news that he is en route to Paris strikes her as odd, but she is interrupted by the servant Giuseppe, who hands her an invitation to a party at Flora’s that evening. Having renounced her old life, Violetta puts it aside. Giuseppe then announces a gentleman caller, and Violetta, thinking it is someone on business, asks for him to be shown in. The visitor turns out to be Alfredo’s father, who starts to address her harshly, taking her for a common fortune hunter. He is impressed at once, however, by her ladylike manners. To clear up the question of money, she shows him receipts from the sale of her belongings. Aware that he is dealing with a woman of dignity and character, the elder Germont asks rhetorically why her past should condemn her. She replies that her love for Alredo has reemed her, but Germont says he must ask a sacrifice. Because the scandal of the liaison makes it impossible for his daughter to make a respectable marriage (Pure Sicome un angelo), Germont is sympathetic but persists, reminding Violetta that she is young and can still make a life for herself, and that Alfredo will eventually tire of her (Un di, quando le venere). She finally gives in, asking Germont to tell his daughter of the sacrifice made for her sake (duet: Ah! Dite alla giovine). After exchanging farewells with Germont, she decides she can only leave, sending Annina with a note accepting Flora’s invitation. As she writes to Alfredo, however, he suddenly appears. She tries in vain to conceal her agitation, begging Alfredo to love her (Amani, Alfredo) as much as she loves him, then saying good-bye. Only when the gardener appears with Violetta’s farewell note does he realize that she has left him. His father reappears and tries to comfort him, reminding him of their native Provence (Di Provenza il mar). Too distraught to listen, Alfredo believes that Violetta has gone back to Baron Douphol; Germont renews his plea, promising forgiveness if Alfredo returns home (No, non undrai rimproveri). Instead, Alfredo sees Flora’s invitation on the table and rushes to follow her to the party. When Flora, mentions to her protector, the Marquis d’Obigny, that she has invited Alfredo and Violetta, he says that the lovers have separated. Women dressed as Gypsies read fortunes (chorus: Noi siamo zingarelle), and Gastone and group of men dressed as matadors hail the prowess of a bullfighter (È Piquillo un bel gagliardo). Alfredo enters alone and starts gambling with forced nouchalance. When Violetta appears on the arm of the baron, the letter orders her not to speak to Alfredo. Tension builds as Alfredo wins at cards and the Baron challenges him by joining the game (ensemble: Qui desiata giungi). Aflredo’s winning streak continues until dinner is announced. Violetta stays behind as the others go into the next room; Alfredo appears, in reply to her summons. Warning him of the Baron’s singer, she succeeds only in intensifying his jealousy; Alfredo forces her to say that she loves the Baron. Then he calls the others in to witness the fact that he is repaying Violetta the money she squandered on him (Ogni sun aver tal femmina), throwing his winning at her feet. Germont unexpectedly enters, denouncing his son’s unworthy behavior (Di Sprezzo degno). The Baron challenges Alfredo to a duel, and Violetta, near fainting, tells Alfredo she does not deserve his contempt.
ACT III: Violetta’s bedroom in Paris, a month later.
Abandoned by Alfredo, the Baron, and almost out of money, Violetta lies dying of tuberculosis. Only the faithful Annina and a friend, Dr. Grenvil, still attend to her. The doctor tells Annina that her mistress cannot last much longer. Sending Annina out to give a few coins to the poor at Carnival time, she rereads a letter from Germont (Teneste la promessa) saying that Alfredo wounded the Baron and left the country but will return to ask her forgiveness, having leraned the truth about her sacrifice. Looking in a mirror, she sees how changed she is by illness and realizes that it is too late, bidding farewell to her past dreams (Addio del passato). As merrymakers are heard outside, Annina announces that Alfredo is on his way. When he arrives, the lovers dream briefly of a new life away from the city (duet: Parigi, o cara), but Violetta falters and cries out against approaching death (Gran Dio! Morir sì giovine). Annina goes to fetch the doctor, who returns with the repentant Germont. Violetta gives Alfredo a miniature portrait of herself as she once was (Ensemble: Prendi, quest’è l’immagine) and urges him to marry and be happy one day. Then, feeling her pain stop, she rises as if reborn, only to fall dead.