Yamadori is a wealthy Japanese citizen of New York in the book and play and a prince in the opera, but in all he is smitten with Butterfly's beauty and wants to add her name to the list of wives he has conveniently married and as conveniently divorced on his visits to his native land.

Butterfly insists that she is an American and cannot be divorced Japanese fashion, and is amazed when Sharpless hints that Pinkerton might have forgotten her and she would better accept Yamadori's hand.
First she orders him out of the house, but, repenting her of her rudeness, brings in the child to show him something that no one is likely to forget.

She asks the consul to write to his friend and tell him that he has a son, so fine a son, indeed, that she indulges in a day dream of the Mikado stopping at the head of his troops to admire him and make him a prince of the realm.

Sharpless goes away with his mission unfulfilled and Suzuki comes in dragging Goro with her, for that he had been spreading scandalous tales about the treatment which children born like this child receive in America.

Butterfly is tempted to kill the wretch, but at the last is content to spurn him with her foot.
At this moment a cannon shot is heard.