In their garret apartment on Christmas Eve, Marcello is painting while Rodolfo writes. They have no firewood, so Rodolfo burns his manuscript to provide some heat. Colline and Schaunard arrive, the latter laden with fuel and food. The landlord Benoit shows up to demand the rent, but the four bohemians feign indignation at his scandalous past and throw him out. As the others go off to celebrate the holiday, Rodolfo stays to finish an article. He is interrupted by Mimì, who requests a light for her candle. Mimì suddenly collapses in a fit of coughing. As she is about to leave, Mimì discovers that she has dropped her key. As they search in the darkness, Rodolfo finds her key and then touches her hand. It is cold, so he offers to warm her hands with his own. He tells of his life as a poet and she describes her work making embroidery. They begin to fall in love.

Mimì and the four young men join the celebrating crowd at the Café Momus. Musetta, who alternatively loves and quarrels with Marcello, arrives with the doddering but wealthy Alcindoro. She pretends that her shoe is too tight and sends Alcindoro off to buy another pair. Musetta and Marcello embrace and everyone orders expensive suppers. When Alcindoro returns, the bohemians run off, leaving him to pay the bill.

A checkpoint in the city, months later, at dawn. Mimì appears, coughing and weak. A message from her brings Marcello out of a tavern. Rodolfo and Musetta are inside, but Mimì refuses to join them. She tells Marcello of Rodolfo’s jealousy and says they must part. Just then Rodolfo comes outside and confesses his fears for Mimi’s health. Overcome, her sobs give her away. The two lovers regretfully agree that they must separate, but then begin to remember happier times. Meanwhile, Marcello discovers Musetta flirting with one of the men in the tavern. Their violent quarrel contrasts with Mimi’s and Rodolfo’s new resolution to stay together until the arrival of spring.

Back in their garret apartment months later, Marcello and Rodolfo long for their lost loves. When Schaunard and Colline arrive, the quartet attempts to forget their sorrows through some horseplay. Musetta appears and announces that Mimì is dying. As a last request, she wants to return to the attic where she met Rodolfo. He helps the fragile girl inside the apartment. Musetta gives her earrings to Marcello, asking him to buy medicine for the dying girl, then goes to buy a muff for Mimì’s cold hands. Colline goes to pawn his overcoat for food. Mimì and Rodolfo revive their love, then Rodolfo steps away to let her sleep. The others return and they all realize that Mimì has died.