Nagasaki, early 20th century. The geisha Cio-Cio-San, called Madame Butterfly, has married an American naval officer, Pinkerton, who deserts her shortly after the wedding. Butterfly bears his son and patiently awaits her husband's return.
One day, the American consul receives a letter from Pinkerton in which he says he has an American wife (his marriage in Japan not being legally recognized in America) and is returning to fetch his child. Pinkerton's ship finally arrives and he sets out to visit Butterfly with his wife Kate.
Filled with remorse, however, he is unable to face Butterfly and leaves Kate alone with her. Butterfly tells Kate that she will give Pinkerton his son if he comes to fetch him. Rejecting a life of disgrace, she kills herself with her father's sword. Pinkerton arrives to find her dead.