At Goro's Tea House, Cho-Cho San, Sylvia Sidney is bidding farewell to her mother and grandfather, stepping into geisha training to support her family. The atmosphere hums with tradition as relatives depart, and Goro introduces Prince Yamadori, a prospective husband, to Cho-Cho San. When Yamadori notes her withdrawal, Madame Goro explains that Cho-Cho San is high-born and not yet accustomed to the geisha lifestyle.
On an American steamship set to spend months abroad, Lieutenant Barton, Charles Ruggles convinces his friend Lieutenant B.F. Pinkerton, Cary Grant, that they should skip the consul’s formal party and instead seek their own amusement. Pinkerton eyes a photograph of a blonde woman tucked away in his trunk, a memento that will color the ensuing days.
Back at Goro's, Mrs. Goro outfits Cho-Cho San for another encounter with Yamadori. Pinkerton and Barton visit the house, greeted by geishas and the music that accompanies their world. They watch a dance performance, and Pinkerton becomes enchanted with Cho-Cho San; she retreats into the garden, frightened by the sudden intensity. Pinkerton follows, and under a screen, he sees her practicing a dance and speaks with her, even as Goro admonishes him. Cho-Cho San runs away, yet a spark is kindled between them.
Yamadori returns to press his suit, but Goro’s scheming angers him when a neighboring geisha reveals she’s accompanied by a naval officer. Yamadori vows never to set foot in Goro’s house again, and Goro’s anger at Cho-Cho San follows. Pinkerton, alone with Barton, learns a troubling pragmatism: in this culture, marriage can be a formality and desertion doesn’t legally shatter a geisha’s life. With that seed of possibility, Pinkerton tells Goro of his intent to marry Cho-Cho San, a decision that will ripple through both families.
Cho-Cho San’s relatives gather at their new house as the marriage is celebrated in a tea ceremony. Cho-Cho San prays before the family altar, where a portrait of her ancestors overlooks the ceremony. Pinkerton asks Barton to keep the relatives away, while he begins to deepen his bond with Cho-Cho San and even teaches her how to kiss.
Weeks pass. Pinkerton returns home to a Cho-Cho San who greets him with warmth. He presents her with a translucent veil, and she offers him a drink and a pipe. While rummaging in Pinkerton’s trunk for pipe cleaners, Cho-Cho San finds a picture of the blonde Adelaide—an inscription to Pinkerton on the back. With a grave face, she asks if he is in love with that woman; he denies it.
Weeks later, their home altar now bears Pinkerton’s portrait, and Cho-Cho San welcomes Pinkerton and Barton with happiness. In a private aside, Pinkerton confides in Barton that he lacks the courage to tell Cho-Cho San that he will leave the following day. Barton suggests they all dine at the hotel, as news of departure hangs in the air. The next morning, the commander of the naval vessel visits their table and mentions they sail tomorrow. Cho-Cho San is shaken.
The next spring, Cho-Cho San is seen with her infant son, and she points to a robin nesting nearby, naming her child “Trouble” for now, with the hopeful promise that the name will change to “Joy” when Pinkerton returns. The scene shifts to America: Adelaide Pinkerton, Sheila Terry, and Pinkerton are together in a garden, a ring on her finger signaling their engagement. She speaks of spring, and Pinkerton, troubled, hints he might reveal something that could upset her.
Back in Japan, Cho-Cho San’s grandfather urges her to marry Yamadori, but she explains that American divorce rules require a judge and years of waiting, unlike the Japanese system. She refuses and declares that she and the house belong to Pinkerton. In response, her grandfather disowns her and banishes her from his home, a rupture that is deeply felt.
Meanwhile, Pinkerton and Adelaide are married in America, while Cho-Cho San learns that the robins nest only once in the American year. The consul confirms the situation, and Cho-Cho San goes to a temple to seek solace. She learns that American naval ships are approaching, and she joyfully tells her son that his father has returned.
At the dock, Pinkerton is met by Adelaide as Barton announces that a party hosted by the consul is to take place that night. Cho-Cho San, hopeful, signals Suzuki to help with Trouble, planning a quiet reunion. They wait through the night by the window, watching for Pinkerton, but morning finds only a sense of waiting and doubt, as Suzuki warns that “men always forget.”
In the end, Pinkerton and Adelaide arrive at Cho-Cho San’s home amid the radiant confusion of kin and visitors. Pinkerton explains that his time is up and that he will never return. Cho-Cho San’s world collapses as she sees Adelaide waiting outside; the truth lands hard—Pinkerton has married the woman from the photograph. She tenderly tells Trouble that his father has taken another woman, then instructs Suzuki to take Trouble to his grandfather to be raised “in the ways of his ancestors.” She returns to prayer, recalling the vow she once heard: "till death do us part." She draws the knife that bears an inscription, wraps Pinkerton’s veil around her neck, and, with a final breath, ends her life. Her last words are a quiet, heartbreaking declaration: > I love you for always.
