Synopsis
Act I

In the first act of Madama Butterfly, Lieutenant B.F. Pinkerton, a sailor with the USS Abraham Lincolnin the port of Nagasaki marries Cio-Cio-San, or, as she is known to her friends, "Butterfly," a 15-year-old Japanese geisha. The Matchmaker Goro has arranged the wedding contract and rented a little hillside house for the newlyweds. The American consul Sharpless, a kind man, begs Pinkerton to forget this plan, when he learns that Butterfly innocently believes the marriage to be binding. (In fact, both the marriage and the lease on the house may be canceled at short notice). The lieutenant laughs at Sharpless' concern, and the bride appears with her friends, joyous and smiling. Sharpless learns that, to show her trust in Pinkerton, she has renounced the faith of her ancestors and, therefore, she can never return to her own people. (Butterfly: "Hear what I would tell you"). Pinkerton also learns that she is the daughter of a disgraced samurai who committed seppuku, and so the little girl was sold to be trained as a geisha. The marriage contract is signed and the guests are drinking a toast to the young couple when the bonze, a Buddhist monk, (uncle of Cio-Cio-San) enters, uttering imprecations against her for having adhered to the foreign faith. The bonze's curses induce her friends and relatives to abandon her. Pinkerton, annoyed, hurries the guests off, and they depart in anger. With loving words he consoles the weeping bride, and the two begin their new life happily. (Duet, Pinkerton, Butterfly: "Just like a little squirrel"; Butterfly: "But now, beloved, you are the world"; "Ah! Night of rapture").

Act II

Pinkerton's tour of duty is over, and he has returned to the United States, after promising Butterfly to return "When the robins nest again." Three years have passed. Butterfly's faithful servant Suzuki rightly suspects that he has abandoned them, but is upbraided for want of faith by her trusting mistress. (Butterfly: "Weeping? and why?") Meanwhile, Sharpless has been sent by Pinkerton with a letter telling Butterfly that he has married an American wife. Butterfly (who cannot read English) is enraptured by the sight of her lover's letter and cannot conceive that it contains anything but an expression of his love. Seeing Butterfly's joy, Sharpless cannot bear to hurt her with the truth. When Goro brings Prince Yamadori, a rich suitor, to meet Butterfly, she refuses to consider his suit, telling them with great offense that she is already married to Pinkerton. Goro explains that a wife abandoned is a wife divorced, but Butterfly declares defiantly, "That may be Japanese custom, but I am now an American woman." Sharpless cannot move her, and at last, as if to settle all doubt, Butterfly proudly presents her fair-haired child. "Can my husband forget this?" she challenges. Butterfly explains that the boy's name is "Sorrow," but when his father returns, his name will be "Joy." The consul departs sadly. But Butterfly has long been a subject of gossip, and Suzuki catches the duplicitous Goro spreading more. Just as things cannot seem worse, distant guns salute the new arrival of a man-of-war, the Abraham Lincoln, Pinkerton's ship. Butterfly and Suzuki, in great excitement, deck the house with flowers, and array themselves and the child in gala dress. All three peer through shoji doors to watch for Pinkerton's coming. As night falls, a long orchestral passage with choral humming (the "humming chorus") plays. Suzuki and the child gradually fall asleep - but Butterfly, alert and sleepless, never stirs.

Synopsis (continued)
Act III

Act three opens at dawn with Butterfly still intently watching. Suzuki awakens and brings the baby to her. (Butterfly: "Sweet, thou art sleeping.") Suzuki persuades the exhausted Butterfly to rest. Pinkerton and Sharpless arrive and tell Suzuki the terrible truth: Pinkerton has abandoned Butterfly for an American wife named Kate. The lieutenant is stricken with guilt and shame (Pinkerton: "Oh, the bitter fragrance of these flowers!"), but is too much of a coward to tell Butterfly himself. Suzuki, at first violently angry, is finally persuaded to listen as Sharpless assures her that Mrs. Pinkerton will care for the child if Butterfly will give him up. Pinkerton departs. Suzuki brings Butterfly into the room. She is radiant, expecting to find her husband, but is confronted instead by Pinkerton's new wife. As Sharpless watches silently, Kate begs Butterfly's forgiveness and promises to care for her child if she will surrender him to Pinkerton. Butterfly receives the truth with apathetic calmness, politely congratulates her replacement, and asks Kate to tell her husband that he must come in half an hour, and then he may have Sorrow, whose name will then be changed to Joy. She herself will "find peace." She bows her visitors out, and is left alone with young Sorrow. She bids a pathetic farewell to her child (Finale, Butterfly: "You, O beloved idol!"), blindfolds him, and puts a doll and small American flag in his hands. She takes her father's dagger--the weapon with which he made his suicide--and reads its inscription: "To die with honour, when one can no longer live with honour." She takes the sword and a white scarf behind a screen, and emerges a moment later with the scarf wrapped round her throat. She embraces her child for the last time and sinks to the floor. Pinkerton and Sharpless rush in and discover the dying girl. The lieutenant cries out Butterfly's name in anguish as the curtain falls.
Synopsis courtesy of Wikipedia.