Scene: Early 20th-century Japan
U.S. Navy Lieutenant B. F. Pinkerton stands on a flowery terrace overlooking the Nagasaki harbor, inspecting the house he has just leased from Goro, a marriage broker who has given him three servants and a geisha wife, Cio-Cio-San, also known as Madama Butterfly. Pinkerton describes the carefree life of a sailor to Sharpless, the American consul. The young Butterfly has captivated his heart, but he knows full well that his marriage contract contains a monthly “renewal option.” When Sharpless warns him that Cio-Cio-San may not take her marriage vows so lightly, Pinkerton callously remarks that one day he will wed a “real” American wife. Meanwhile, Cio-Cio-San sings joyfully of her wedding day. As she enters with her friends, she tells Pinkerton about her life as a geisha. Her relatives hasten in to quibble about the marriage. Quietly, Cio-Cio-San takes Pinkerton aside to show him her dowry of treasures, telling him she will embrace his Christian faith. The Imperial Commissioner marries Cio-Cio-San and Pinkerton, and during the celebration, Cio-Cio-San’s uncle, a Buddhist priest, curses her for renouncing her ancient religion. In a heated moment, Pinkerton sends the guests away. Alone with Butterfly, he dries her tears, and they sing together of their love.
As Suzuki prays for help from the gods, her mistress, Cio-Cio-San, stands looking out onto the harbor praying for her husband’s return. Sharpless brings her a letter from Pinkerton, but before he can read it, Goro enters with a suitor, Prince Yamadori. Cio-Cio-San rejects them both, saying that one day her husband will return for her and their son, Sorrow. Moved with pity for the desperate Cio-Cio-San, Sharpless leaves without revealing the contents of the letter. Meanwhile, Cio-Cio-San sees Pinkerton’s ship in the distance and begins a vigil with her son as night falls on the moonlit house.
Dawn breaks, and Suzuki implores her mistress to rest. Cio-Cio-San sings Sorrow a lullaby, and soon Pinkerton arrives with Sharpless and his new wife, Kate, who waits in the garden. Pinkerton begs Suzuki to persuade Cio-Cio-San to give the child to him and Kate. Suzuki promises to help, but Pinkerton is filled with remorse and flees the house. When Cio-Cio-San finally encounters Pinkerton and Kate, she instantly realizes who this new woman is. She promises to give them her son, but only if they return later. Alone, Cio-Cio-San takes out her father’s dagger, bids her son a last farewell, and pushes him away. She stabs herself. Hearing her cries, Pinkerton rushes to the house, crying, “Butterfly! Butterfly!”