The Greek Island
Scene 1: Corrado's ship
The island is controlled by the corsairs, or pirates. A chorus introduces Corrado, the chief corsair, who is in exile. He laments his present condition: Tutto parea sorridere / "The world seemed to smile upon my early life". But he receives a letter containing military intelligence about the Turkish Pasha, Seid. It convinces him to set sail with his comrades, and he immediately starts rallying the troops: Sì, di Corsari il fulmine / "Yes, the lightning blow of the Corsairs shall I myself strike".
Scene 2: Medora's home
Medora is alone, and anxious for Corrado's return. She picks up her harp and sings a beautiful, but vaguely sinister aria; some sixth sense seems to be telling her that things are bound to turn out badly: Non so le tetre immagini / "Dark forebodings I cannot banish from my thoughts". When Corrado finally arrives, the two sing a duet that captures both the serenity of their love and the uncertainty of their future. Medora pleads with Corrado not to leave, but finally he departs to confront the Pasha.
Scene 1: The harem
The slave girls in Pasha Seid's harem are looking after Gulnara, the Pasha's favorite. However, Gulnara is unhappy about the Pasha's attentions. She chafes at life in the harem, and longs for freedom and true love: Vola talor dal carcere / "At times my thought flies free from its prison". A eunuch brings Gulnara an invitation to a celebratory banquet anticipating the Pasha's victory in the impending sea battle with the corsairs. She expresses a hope of something better awaiting her in life: Ah conforto è sol la speme / "Ah, comfort lies only in hope for this lost soul" and the ladies of the harem tell her that "you are everyone's hope".
Scene 2: The banquet
Seid and his men express their feelings that Allah will protect them: Salve, Allah! tutta quanta / "Hail Allah! All the earth resounds with his mighty name". A slave asks the Pasha if a Dervish who has apparently escaped from the corsairs might be admitted. Seid grants an audience and questions him. Suddenly everyone notices flames at sea: the Pasha's fleet is burning. As the Dervish whips off his disguise and reveals himself to be Corrado, his corsairs invade the banquet, and a battle takes place. At first, it seems that Corrado and his men will win, but he makes a fatal mistake. Seeing that the harem is burning, Corrado decides to rescue Gulnara and the other women. This gives the Pasha and his men time to regroup. They take Corrado prisoner and Seid confronts him - Audace cotannto, mostrarti pur sai? / "Yet so bold do you stand before me" - as he condemns Corrado to a grisly death, in spite of pleas from Gulnara and the harem to spare him for saving their lives.
Scene 1: Seid's quarters
Seid is enjoying his victory, but he is not entirely satisfied: Cento leggiadre vergini / "A hundred lissom virgins asked love of me" he says, but "my heart beats only for Gulnara". He is afraid she has fallen for the dashing Corrado. Sending for her, he proclaims his basic credo of revenge: S'avvincina il tuo momento / "Your moment approaches, dread thirst for vengeance". When she enters, he challenges her and she tells him that he is right; he threatens Gulnara, but she defies him and the Pasha storms out of the room.
Scene 2: The prison
Corrado is in prison and assumes that he is doomed: Eccomi prigionero! / "Here am I a prisoner". Having bribed a guard to let her into his cell, Gulnara vows to help him, handing him a knife to kill Seid. Corrado rejects her offer, citing his honor as a combatant. He also senses her deep feelings for him, and tells her that he is in love with Medora. Gulnara leaves, saying that she will kill Seid. In a brief interlude, the stormy music, which opened the Prelude, is heard again; this time, it accompanies a murder. On her return Gulnara reports that she takes all the blame for killing the Pasha: Sul capo mio discenta, fierro Iddio / "Upon my head, grim God, let your dread lightning fall". With their enemy gone, she and Corrado resolve to escape together to the corsairs' island.
Scene 3: The Greek island
Near death after taking poison, Medora is convinced and she will never see Corrado again. The ship carrying Gulnara and Corrado appears in the distance and, when they arrive, Corrado and Medora throw themselves into each other's arms. In a trio with each character expressing his/her feelings, Corrado begins by explaining how he and Gulnara became free: Per me infelice vedi costei / "Unhappy for my sake you see this woman; she risked her life to save mine". However, their joy does not last for long, for Medora dies. With his men trying to stop him, Corrado leaps from a cliff to his death as the opera ends.