The story: Act I. The action unfolds on Cyprus, under Venetian rule in the 16th century. The scene is outside the castle, residence of Otello, governor of the island, facing the port. It is night. A furious storm churns the sea, and a crowd of Venetian citizens and soldiers helplessly watch while the ship of the Moor Otello desperately tries to make it into port. Only Iago, one of Otello's men, does not participate in the general apprehension for the safety of his leader: he hates Otello, because Otello has promoted Cassio captain instead of him; he meditates revenge. The crowd is jubilant as Otello finally lands safely and announces that the Turkish fleet has been defeated. When the Moor enters the castle, the fireworks start and all drink to his victory. In the midst of the rejoicing, Iago starts to weave the scheme that will lead to his commander's downfall: he treacherously insinuates to Roderigo, who had revealed to Iago his love for Otello's wife, Desdemona, that Captain Cassio also feels the same affection for the woman. Then Iago gets Cassio drunk, and incites a fight between the two men, but the dangerous duel that starts between them is stopped by Montano. However, the peacemaker is wounded by Cassio. Iago sounds the alarm, swelling the episode out of proportion until the crowd is in tumult. Called back by the shouts and noise, Otello, falsely informed by Iago, punishes Cassio and demotes him. This is a first victory for Iago, who exults.
Act II. A ground-floor hall in the castle; a door leads to the garden. Iago continues his plan: he suggests to Cassio to ask Desdemona to intercede in his favour with Otello. In a monologue, Iago describes his cynical view of life, then he plants the seeds of jealousy in the Moor's soul, leading him to suspect that there is a secret love between Cassio and Desdemona. Thus, when the woman, arriving from the garden, tries to intercede for the degraded captain, Otello's jealousy is enflamed, and he brusquely refuses the request. Once again, Iago insinuates having heard some compromising words murmured by Cassio in his sleep, and, having obtained with the help of his wife Emilia a handkerchief that Otello had given to his young wife, affirms having seen it in Cassio's hands. For Otello, this is proof enough. He vows terrible revenge.
Act III. The great hall of the castle. The lookout has sighted the galley bringing Venetian ambassadors. Unsuspecting Desdemona once again asks Otello's pardon for Cassio, but all she gets for an answer is Otello's request for her to show him the handkerchief he had given her as a talisman. Since she cannot give it to him, outraged, he accuses her of being a courtesan and repulses her. Alone, he mourns his lost happiness. But the arrival of Iago revives him; the henchman wants to complete his web of lies and prepares more deception. He manages to get Otello to listen, hidden, to a conversation he has with Cassio about a courtesan, making Otello think they are talking about Desdemona. Otello pledges to kill his unfaithful wife. But in the meantime the ambassadors have landed and announce that Otello has been recalled to Venice and that his place will be taken by Cassio. In the presence of the dignitaries, Otello, by now completely out of his mind, tells his wife "we will sail tomorrow" and brutally grabs her arms and throws her to the ground. Iago puts in motion the last part of his diabolical plan, urging Roderigo to kill Cassio, while Otello damns Desdemona; all flee in horror. Delirious, the Moor falls to the ground senseless. Iago triumphs over the inert body of his commander.
Act IV. Desdemona's room. She is getting ready to go to bed, aided by Emilia. She is hurt by Otello's attitude toward her, for which she finds no explanation. She has just finished her prayers when Otello enters. He openly accuses her of having been unfaithful to him, even though, unheeded, Desdemona proclaims her innocence. He has already condemned her and proceeds to strangle her. Emilia returns announcing that Roderigo has been killed while trying to assassinate Cassio. Seeing Desdemona dead, she accuses Otello and cries that he has killed an innocent woman. Iago appears, and Emilia reproaches him for his intrigue; his only answer is to flee. Otello, dismayed and suddenly aware of the trap into which he has fallen gives a last kiss to his beloved wife and stabs himself.