The scene is set in the Latin Quarter, Paris. It is a cold Christmas Eve in the garret shared by the bohemians: Rodolfo, a poet, Marcello, a painter, Colline, a philosopher, and Schaunard, a musician. Marcello is at work on a painting. Rodolfo is trying to write. He suggests that he sacrifice his tragedy for fuel, and the manuscript goes into the stove. Colline enters, closely followed by Schaunard, who has managed a windfall. He is laden with fuel and food. Benoit, their landlord, wants the rent. The quartet invites him in and then feigns horror as the old man boasts of his conquests. With mock indignation, they eject him.

As the others go off to the Café Momus to celebrate, Rodolfo stays behind to finish an article. A timid knock interrupts him. He discovers a frail young woman at the door. It is Mimi, who requests a light for her candle. Rodolfo asks her to come in and lights her candle with his. Mimi suddenly collapses in a fit of coughing. As she recovers, a draught blows out both candles. In the confusion Mimi drops her key. As they search in the darkness, Rodolfo slips her key into his pocket, then touches her hand. Tenderly, Rodolfo offers to warm her hands with his own. He tells her of his life as a poet and she describes her work making embroidery. Voices call up from the street below. As they leave to join their friends, Rodolfo confesses that he has fallen in love.

A happy crowd swirls about the Café Momus. The dashing Musetta, who alternately loves and quarrels with Marcello, enters on the arm of the doddering but wealthy Alcindoro. When she sees Mimi and the four young men, she pretends that her shoe is pinching. She sends Alcindoro off to have it fixed Musetta and Marcello embrace. Joining the others, they order an expensive supper. As Alcindoro returns from the cobbler’s shop, they run off, leaving him to pay the bill.

At the gate of the city, months later, at dawn, Mimi comes to an inn. Coughs rack her and she is very weak. A message from her brings Marcello out of the tavern. Rodolfo and Musetta are inside, but Mimi refuses to join them. She tells Marcello of Rodolfo’s jealousy and says they must part. Just then Rodolfo comes out to look for Marcello. Mimi hides and overhears Rodolfo confess his fears for her health. Overcome, her sobs give her away. Regretfully, the two lovers remember happier times. They agree that they must separate. Meanwhile, Marcello discovers Musetta flirting with one of the men in the tavern. Their violent quarrel breaks through Mimi and Rodolfo’s poignant farewell.

Back in the garret, Marcello and Rodolfo long for their lost loves. Surreptitiously Rodolfo fingers the little bonnet he bought for Mimi. When Schaunard and Colline return, the four friends attempt to forget their sorrows and a frolic ensues. Just as the fun is at its height, Musetta enters to tell them that Mimi is dying. As a last request, she has asked to be brought back to the attic where she had been so happy with Rodolfo. Rodolfo helps the fragile girl to a cot and gently supports her. Mimi coughs and Rodolfo takes her hands to warm them. Musetta gives her earrings to Marcello, asking him to buy medicine for the dying girl. Colline goes off to pawn his overcoat to buy food. Musetta leaves to find a muff for Mimi’s cold hands. Mimi and Rodolfo revive their love. The others return with provisions. Before Rodolfo, they become aware that it is too late. He turns and reads the news in their faces. With a cry, he falls on Mimi’s lifeless body.