Violetta throws a party attended by her “protector” Baron Douphol and by her friends, including Flora, a fellow courtesan, and Gastone, a young aristocrat. Gastone introduces Violetta to his friend Alfredo Germont, one of Violetta’s greatest admirers. Gastone invites Alfredo to offer a drinking song, and Alfredo sings the praises of wine and the love it inspires. Violetta joins him, urging everyone to enjoy the fleeting pleasures of love and life.
As the guests move into the ballroom, Violetta has an attack of faintness, an unwelcome reminder of her quickly declining health. Alfredo urges her to abandon her exhausting way of life. He tells her that he has loved her since the moment he first saw her. Violetta tactfully suggests that she is not the kind of woman he should fall deeply in love with; nonetheless, she invites Alfredo to visit her again. When her guests have left, Violetta muses over his declarations of love. Disturbed to discover that her own emotions have been deeply stirred, she resolves to forget Alfredo and devote herself to the shallow pleasures of the courtesan’s world.
Alfredo has been living for three months with Violetta in her country house. He is ashamed to discover that she has been secretly selling her possessions to meet their expenses.
Violetta receives an invitation from Flora to a party in Paris, a reminder of the life Violetta has left behind for Alfredo. An unexpected visitor arrives: Giorgio Germont, Alfredo’s father. Germont asks her for a great sacrifice: his daughter’s marriage prospects have been threatened by Alfredo’s scandalous association with Violetta. Germont convinces her that leaving Alfredo would be the most generous, selfless thing she could do for him. Violetta knows that because she is mortally ill, any future happiness is unlikely without Alfredo. She writes two letters: the first is an acceptance of Flora’s invitation; the second is addressed to Alfredo.
When Alfredo returns, Violetta attempts to disguise her agitation. Desperately assuring him of her love, she leaves for Paris. Alone, Alfredo reads Violetta’s letter, which informs him that she is returning to Baron Douphol. Germont returns to console his son, but Alfredo sees Flora’s invitation and, unaware of Violetta’s sacrifice, vows revenge for her apparent faithlessness.
That evening, Flora’s guests are entertained by masqueraders dressed as gypsies and matadors. Alfredo arrives, alone; Violetta enters shortly afterward with Baron Douphol. Alfredo goes to the card table, where he is soon joined by the Baron, but Alfredo’s good luck at gambling is unmatched. When the guests sit down to supper, Violetta privately begs Alfredo to leave. Furious, he insults her in front of everyone, throwing his winnings at her as “payment” for their time together. The elder Germont comes in, joining the assembled crowd in expressing their outrage.
Violetta is near death, alone and impoverished. She reads a letter from Giorgio Germont: Alfredo had fled abroad after wounding Baron Douphol in a duel, but now that he knows the true circumstances of Violetta’s sacrifice, he is on his way back to her. When he returns, the lovers are reunited with tender words. Giorgio Germont also arrives, filled with remorse, but there is nothing to be done. Violetta feels a sudden rush of exhilaration as her pain disappears, and she dies.