An attic in the Latin Quarter of Paris, Christmas Eve. Rodolfo and Marcello complain about the bitter cold. They burn the manuscript of Rodolfo’s latest play and they and their friend Colline enjoy the brief warmth. Schaunard arrives with wood, food and wine that he has earned working for an eccentric Englishman. The friends plan to go and eat in the Latin Quarter but are interrupted by Benoît, their landlord, who demands the rent. They offer him wine and, when Benoît boasts of his sexual prowess, pretend outrage and push him out. Marcello, Colline and Schaunard head off, leaving Rodolfo to finish an article. A girl knocks at the door and asks for a light for her candle. As she is leaving it flickers out again and she realizes that she has lost her key. Rodolfo’s candle also goes out as they search for it. Rodolfo tells the girl about his life as a poet. She tells him her name, Mimì, and describes her life as an embroiderer. Schaunard, Colline and Marcello shout up to Rodolfo to hurry. Mimì asks if she may join them at the Café Momus, and the lovers leave together.
The Latin Quarter. Rodolfo and Mimì wander through the Christmas Eve crowds. Rodolfo introduces Mimì to his friends. As they sit down to supper, Marcello’s ex-girlfriend Musetta appears with Alcindoro, her rich admirer. Musetta decides to seduce Marcello and launches into a song. She then complains of a painful foot, and dispatches Alcindoro to buy new shoes. She and the bohemians quickly depart, leaving Alcindoro with both their bills.
Outside the Barrière d’Enfer. Workers arrive at the city gates. Mimì meets Marcello outside a tavern. When she learns that Rodolfo is there she becomes agitated, and tells Marcello that Rodolfo’s jealousy is destroying their relationship. She hides as Rodolfo appears. Rodolfo tells Marcello that Mimì’s flirtatious behaviour has incensed him. But soon he reveals the real reason for their separation: she is very ill and he is too poor to help her. They hear Mimì crying and coughing. Rodolfo hurries to her, while Marcello, suspicious of Musetta’s flirtatious laughter, hurries back into the inn. While Marcello and Musetta quarrel and separate, Rodolfo and Mimì decide to postpone their separation until the spring.
The attic, autumn. Marcello and Rodolfo pretend not to miss their former girlfriends but admit that they do. Schaunard and Colline arrive with bread and a herring and the four eat and amuse each other. Suddenly Musetta enters. She has brought Mimì, who is desperately ill: Musetta explains that Mimì has begged to be taken to Rodolfo. Mimì rallies and greets the friends. Musetta instructs Marcello to sell her earrings to pay for medicine and a doctor. Colline leaves with Schaunard to pawn his coat. Mimì, alone with Rodolfo, expresses her boundless love for him, and the lovers reminisce about their first meeting. The others return with a muff and medicine, promising that a doctor will come – but Mimì dies unnoticed while they are preparing her medicine.