Benjamin Franklin Pinkerton, a young US Navy lieutenant stationed in Japan, has arranged with Goro, a marriage broker, to acquire a 15-year-old Japanese bride, Cio-Cio-San(also known as Butterfly). Pinkerton has taken a 999-year lease on a home overlooking Nagasaki harbour; this lease, as well as his marriage, can conveniently be cancelled at a month’s notice. Sharpless, the American Consuland Pinkerton’s friend, arrives to witness the signing of the wedding contract. He warns Pinkerton not to treat the marriage lightly, as his bride-to-be is truly in love with him. Pinkerton claims to be smitten with Butterfly, but he then proposes a toast to the American woman he will one day wed. Butterfly arrives. She tells Sharpless that her family was once wealthy, but hard times forced her to become a geisha. After Butterfly admits that her father is dead, Goro tells Pinkerton that he committed ritual suicide at the Emperor’s command. Butterfly’s relatives arrive and the formalities proceed. The festivities are interrupted when the Bonze, Butterfly’s uncle, enters to denounce her for forsaking their ancestral religion. Pinkerton angrily orders the guests to leave. He comforts the distraught Butterfly, and the newlyweds proclaim their love.