A square in Amiens, with an inn
A group of students, drinking outside the inn, mingles with the townspeople. The student des Grieux joins his friends. In answer to some chaffing by Edmondo, one of the students, he assures them that he has never known the pangs of love. To humor them he accosts a group of girls, asking if one of them will prove to be the one to ignite the spark in him.
A coach arrives, depositing Manon, her brother Lescaut and Geronte, an elderly rich tax-collector. Des Grieux is struck by Manon's beauty, and seizes the opportunity to address her when she is alone. In answer to his eager questions she tells him she is being sent to a convent by her father. She agrees to meet him later. Des Grieuz rhapsodises about her and his fellow students are amused to find him so suddenly in love.
A brief conversation between Lescaut and Geronte shows them beginning to understand each other. Lescaut has an eye to the main chance and Geronte is obviously interested in Manon and invites Lescaut to supper. But then he waits until Lescaut's attention is turned elsewhere (he joins some students in a game of cards) and makes an arrangement with the innkeeper to have a coach ready in an hour's time. He intends to abduct Manon, but he is overheard by Edmondo who warns des Grieux and they plan to outwit Geronte.
When Manon reappears she tells des Grieux that all her joy in life is gone; but she begins to respond to his declaration of love. However when he warns her of Geronte's intentions and urges her to fly with him instead, she is most reluctant. Finally she yields and they escape, urged on by Edmondo, just as Geronte appears.
Edmondo tells him what has happened and he then tells Lescaut who, after a burst of rage, becomes philosophical, consoling Geronte with his account of Manon's character: she will not long be happy with a poor student and since he can see Geronte has such a "fatherly" interest in her he feels that the future happiness of Geronte with Manon is assured, with himself added to the menage as "son."
An elegant room in Geronte's house
Manon is putting the finishing touches to a stylish toilette when her brother appears. He congratulates her (and himself, as architect of the scenario) on her present position. He had tracked her down and lured her away by dazzling her with Geronte's wealth. But Manon tells him she misses des Grieux and would now prefer love and poverty to her present loveless wealth. Lescaut tells her he has been helping des Grieux to make his fortune by teaching him to cheat at cards.
Some singers serenade Manon with a madrigal written by Geronte. When she complains of boredom Lescaut descides to go and find des Grieux and tell him where to find her.
Manon is instructed in courtly dancing, to the rapturous admiration of an audience of Geronte and his friends. She dances with Geronte and sings him a pastoral ditty, describing a shepherdess pining for her shepherd. The company leaves for an outing and Manon waits for her sedan chair.
Des Grieux enters and reproaches her for her faithlessness, to which she offers a variety of answers: she is sorry, she did it all for him, she loves him passionately. He is won over by her spell and reaffirms his love. In the middle of their ecstatic reunion Geronte comes back. Manon answers his reproaches with a mirror, asking him to compare himself with her and des Grieux. He departs, promising to return. As the lovers prepare to depart Manon expresses regret at leaving her life of luxury, but when des Grieux upbraids her and accuses her of bringing him to a life of shame she promises to be good.
Lescaut rushes in out of breath to tell them that Geronte has been to the police and that Manon will be punished with deportation. Manon delays their departure by trying to collect as many jewels as possible, and when the arresting party, headed by Geronte, confronts the lovers, the jewels fall from her cloak. As she is taken away Lescaut restrains des Grieux as he draws his sword, warning him that he must stay free to save Manon.
A square near the harbor of Le Havre before dawn
Manon is in a cell waiting to be deported to America. Des Grieux and Lescaut have made a plan to save her and although nervous of the outcome Manon is persuaded to try to escape. But there is a commotion and Lescaut rushes in to warn des Grieux that the plan has failed.
Manon, with the other girls being deported, is led out of the building and a sergeant calls the roll while the townspeople comment freely on the proceedings and the individual girls. Lescaut tells them a tall story about Manon having been torn away from the arms of her lover, rousing their sympathy.
Des Grieux stands with her for as long as possible. She tells him to leave her, forget her and return to his father. When they come to drag Manon away he resists at first, but then turns to the captain of the waiting ship and begs to be allowed to go with her, as cabin boy if necessary. The captain accepts him jovially - "so you want to populate America, do you?" and des Grieux joins the ship as cabin boy.
A desert plain near New Orleans
Des Grieux tries to support and encourage Manon who is weak from thirst and exhaustion. She begs him to try and find water and when he has gone laments her sad fate. He returns unsuccessful and she dies in his arms. He flings himself on her body.