Alfredo has won Violetta’s love. For several months, they have been living happily together in Violetta’s country house.
Violetta’s maid, Annina, tells Alfredo reluctantly that Violetta has been selling off her property to pay for the life she’s now leading. Realizing she has been paying his expenses, Alfredo leaves for Paris immediately to stop this. In his absence, Violetta gets a visit from Alfredo’s father, Giorgio Germont.
He’s a well-to-do businessman who believes the courtesan is ruining his son’s reputation. And, he tells her their illicit love affair is the reason he can’t marry off his daughter.
At first, Violetta assumes Germont wants her to leave Alfredo until a wedding can take place. But that alone won’t satisfy the old man. He reminds her that her past will always haunt them, and that true love can never be hers. In despair, Violetta tells him Alfredo is all she lives for, and such a sacrifice would kill her.
In the months she’s been in the country with Alfredo, her health has improved substantially and she believes she has escaped her past – and her illness. Giorgio cruelly tells her that her beauty will fade eventually and that Alfredo, like all men, will grow tired of her. Succumbing to his cruelty, Violetta agrees to Germont’s demands, asking only to be embraced as a daughter and to allow her to break the news to Alfredo.
Having won, Germont leaves Violetta to decide how to break it off with Alfredo. She writes him a letter and plans to leave before he returns. Just then, Alfredo surprises her. She says she’s leaving for a short while but vows to return. Then, turning to leave, she frantically confesses her love.
Alfredo reads the letter and is crushed. His father reappears to offer consolation and to ask him to come home to his family. Angrily rejecting this suggestion, Alfredo notices an invitation for that evening from Flora, one of Violetta’s friends, and he concludes this is where he will find her.
Scene Two. A magnificent party, with gambling, dancing, entertainment and gypsy fortune-tellers, is underway. Violetta has returned to her former lover, Baron Duphol, and arrives with him. Alfredo enters, to the surprise of everyone. He gambles with the Baron and wins a substantial amount.
Violetta begs Alfredo to leave, but he forces her to explain her behavior. In desperation, and to protect Alfredo’s father, she says she no longer loves him. At this, Alfredo calls the guests to witness that he pays his debts in full and throws his winnings at Violetta. Flora’s guests are outraged at his cruel behavior, and the Baron challenges Alfredo to a duel.
It’s winter, and the scene is Violetta’s bedroom. Her health has declined. The Baron has left her. And her money is almost gone. She tells Annina to give half of what little remains to the poor.
She has gotten a letter from Alfredo’s father explaining that the Baron was wounded in his duel with Alfredo, and that Alfredo has left Paris. He tells her his son now knows the truth of her sacrifice and that they will both soon return to ask her forgiveness. Too late, she cries, and in a magnificent aria, she realizes her life will soon be over.
Alfredo arrives and for a moment, he convinces her she will recover and again be happy. She gives Alfredo a locket and asks that he give it to the woman he will one day meet and marry. She asks him to be happy, and remember her. Reconciled to both father and son, and no longer bound by social convention, Violetta’s sacrifice is complete as the curtain falls.