Montparnasse. The poet Rodolfo and the painter Marcello are struggling to keep warm in their attic apartment on Christmas Eve. Rodolfo sacrifices his latest manuscript to the stove. The philosopher Colline enters and they watch the play burn. In comes the musician Schaunard with food, fuel and wine. As the young men celebrate their sudden good fortune, Benoît the landlord enters to collect the rent. They get him drunk and ply him with questions about women, then shove him out, feigning indignation at his supposed immorality. Marcello, Colline and Schaunard set out for the Café Momus, leaving Rodolfo alone to finish an article. He hears a timid knock: it is a pretty neighbor whose candle has gone out on the stairs. She suddenly feels faint, and he revives her with a little wine and relights her candle. She realizes she has lost her key, and as they both bend down to look for it, he finds it and slips it into his pocket. Their hands meet under the table, hers icy cold. He asks her name. She is called Mimì, and she lives alone in a garret where she embroiders flowers. The two are instantly and madly enamored and leave for the Café Momus to join Rodolfo’s friends.

The Latin Quarter. Everyone is in the street–selling, shopping, dining, celebrating. Rodolfo buys Mimì a lovely gift and they join the others at a table at the Café Momus to order supper. Parpignol the toy-vendor passes by with jubilant children in his wake. A commotion accompanies the entrance of the spectacular Musetta, once Marcello’s lover, upon the arm of the aged and wealthy Alcindoro. Musetta sings a chic waltz–a hymn to her own appeal–then makes a scene over a too-tight shoe. She sends Alcindoro off with it to the cobbler’s and falls into Marcello’s arms. The military band passes by, and the friends follow the soldiers, leaving Alcindoro to pay the bill when he returns.

A gate to the city. A cold dawn breaks as milk women, scavengers, farmers, and truckmen wait to be admitted. Mimì arrives and sends a message to Marcello to come out of the warm, lively tavern to talk to her. She explains that Rodolfo is so jealous that she fears they must part. Rodolfo comes out of the tavern in search of Marcello, and Mimì hides. Rodolfo tells Marcello that he wants to separate from Mimì because of her flirtatiousness. Marcello doesn’t believe him, and Rodolfo confesses his real fear that their poverty aggravates her declining health. Mimì weeps and coughs violently, revealing her presence. Rodolfo rushes to her. They gently decide to part. Marcello hears Musetta’s laughter from the tavern and soon re-emerges with her in the heat of a quarrel over her flirtatiousness. While they hurl epithets, Mimì and Rodolfo postpone their parting until the spring.

Montparnasse. Back in the attic, Rodolfo longs for Mimì, of whom he has had no news, and Marcello pines for Musetta, who is with a wealthy patron. Colline and Schaunard bring a little food, and the friends seek to lift their spirits with a frolic, which turns into a mock duel. In the midst of the fun Musetta bursts in, saying she has met Mimì in the street. The girl is desperately ill and wants only to be brought up to Rodolfo. Rodolfo brings Mimì in and holds her icy hands. They have nothing to give her. Musetta takes off her earrings and gives them to Marcello to sell. Colline goes to pawn his coat. Musetta runs off to get a muff for Mimì’s hands. Left alone, Mimì and Rodolfo relive and proclaim their love. Musetta and the others return, bustling, Musetta praying, but it is too late. While they prepare medicine for her, she slips away. As the others stand dazed, Rodolfo collapses upon her: “Mimì! Mimì!”