The American naval officer Benjamin Franklin Pinkerton is looking for a house in Nagasaki for the duration of his posting to Japan. In keeping with Japanese tradition he agrees a contract with Goro, a real estate and marriage broker which provides him with a house and a Japanese bride, the geisha girl Cio-Cio-San, also known as “Butterfly”, for a term of 999 years. The key point of this agreement is that Pinkerton is allowed to cancel both the marriage and the rental agreement at any time. On the day of the wedding he waits impatiently for his bride. He regards the Japanese wedding ceremony as no more than a tiresome formality to be got out of the way as soon as possible. He is greeted by the American consul Sharpless. In the light of Pinkerton’s enthusiasm for his nonbinding rental and marriage contracts, he advises him not to treat this relationship too recklessly. Cio-Cio-San, on the other hand, takes the marriage very seriously. She has already been to the American consulate to find out about America and to the Christian mission to take her husband’s faith. Once Cio-Cio-San appears together with her friends and relatives, the ceremony can be completed. The celebrations which follow are abruptly interrupted by her furious uncle Bonzo. He has learned that Butterfly has renounced her Japanese religion and curses her. The rest of the family also rejects her. That evening Butterfly is made ready for her wedding night by her confidant Suzuki. The enamoured Pinkerton can hardly wait to be alone with his “toy”. Butterfly confesses that she truly loves him.
Three years have passed since Pinkerton’s departure. Ostracised by society and her family, Butterfly lives alone with Suzuki. While Butterfly waits resolutely each day for her husband to return, Suzuki has doubts whether Pinkerton will keep his promise to return. Sharpless visits Butterfly to deliver a letter from Pinkerton. His cautious efforts to prepare her for the news that Pinkerton is on the way to Japan, though not to see her, fail. Cio-Cio-San prevents him from reading out the letter which contains the bitter truth. Though Butterfly is in desperate need of money, she rejects the rich Yamadori when he asks for her hand. She believes too strongly in her “American” marriage, which – unlike a Japanese one – is binding. When Sharpless advises her to accept Yamadori’s proposal, Butterfly shows him her child, Pinkerton’s son – whom she sees as the symbol of her unbreakable bond with Pinkerton. Cannon fire announces the arrival of a ship. Butterfly is convinced: this must be Pinkerton. She and Suzuki spread out flowers to welcome him. Then, with the child, she waits all night for Pinkerton.
By daybreak Pinkerton still has not arrived. Butterfly lies down exhausted, ready for sleep. Ultimately Sharpless and Pinkerton enter accompanied by Pinkerton’s new wife Kate. Sharpless reveals to Suzuki that the couple has come to take the child away with them to America. Pinkerton, who avoids any encounter with Butterfly, withdraws from the situation and runs away. When Cio-Cio-San wakes and sees this foreign woman, she understands immediately. However, she is only prepared to hand the child to Pinkerton himself. Suzuki attempts to stay with her but Butterfly sends everyone away. She says farewell to her life. Then she commits suicide with her father’s dagger.