Near Olivia’s house, Feste the clown comes across the person who he thinks is Cesario and tries to bring him to Olivia’s house. This individual, however, is actually Viola’s twin brother, Sebastian. Sebastian, of course, is confused by Feste’s claims to know him. Sir Toby and Sir Andrew then find them. Sir Andrew, thinking that Sebastian is the same person he was about to duel a few minutes before, attacks him. But Sebastian, unlike Viola, is a scrappy fighter, and starts to beat Sir Andrew with his dagger, leading the foolish nobleman to cry for mercy. The bewildered Sebastian wonders if he is surrounded by madmen and tries to leave. But Sir Toby grabs him to prevent him from going. The two exchange insults, and Sebastian and Sir Toby draw their swords and prepare to fight.

Suddenly, Olivia enters. She sees Sir Toby preparing to fight the person who she thinks is Cesario. Angrily, she orders Sir Toby to put away his sword and sends away all the others. She begs Cesario to come into her house with her. Sebastian is bewildered, but Olivia does not give him time to think, and the still-confused Sebastian agrees to follow her, saying, “If it be thus to dream, still let me sleep!” (IV.i.59).

Inside Olivia’s house, Maria, Sir Toby, and the other servants have locked Malvolio into a small, dark chamber. Maria asks Feste to put on the robes of a clergyman and pretend to be Sir Topas, a fictional curate, or priest. Sir Toby and Maria then send Feste to talk to the imprisoned Malvolio in the voice of Sir Topas while they listen in on the conversation.

Pretending to be the priest, Feste addresses Malvolio, who cannot see him inside his prison. Malvolio tells Feste that he is not insane, and Malvolio begs Feste to get him out of the locked room. But Feste deliberately misunderstands and misleads the steward. He tells Malvolio that the room is not actually dark but is full of windows and light and that Malvolio must be mad or possessed if he cannot see the brightness. Malvolio denies Feste’s claims, and he urges Feste to question him in the hopes of proving his sanity. But Feste uses ridiculous questions and then contradicts the steward’s answers. He concludes by telling Malvolio he is still mad and must remain in the darkness.

Sir Toby and Maria are delighted by the joke but are also tiring of it. Sir Toby is worried that Olivia, already offended by his drinking and carousing, might catch him in this prank. They send Feste back to Malvolio, where Feste—now using both his own voice and that of Sir Topas, as if the two are having a conversation—speaks to Malvolio again. Malvolio swears he isn’t crazy, and begs for paper, ink, and light with which to write a letter to Olivia. Feste promises to fetch him the items.

Elsewhere in the house, Sebastian is wandering, dazed yet happy. He is very confused: he doesn’t seem to be insane, and yet a beautiful woman—Olivia—has been giving him gifts and wants to marry him. He wishes he could find Antonio to discuss the situation with him. He states, however, that when he went back to their inn, Antonio was nowhere to be seen. Olivia now returns with a priest, asking Sebastian (who she still thinks is Cesario) if he is still willing to marry her. Sebastian happily agrees, and they go off to get married.

Sebastian briefly takes center stage in these scenes, but he fails to make much of an impression as a character in his own right: his principal role is to serve as a male substitute for his resourceful and attractive twin sister, Viola. Sebastian’s primary state of mind in these scenes is total confusion, which is understandable. Having arrived in a country that he has never seen before, he is suddenly surrounded by people who seem to think they know him and who have extreme attitudes toward him: some want to kill him, while others appear to be in love with him. It is not surprising that, after trying to fend off the insistent Feste and being abruptly attacked by Sir Andrew, Sebastian asks in bewilderment, “Are all the people mad?” (IV.i.24). Olivia’s approach forces him to wonder about his own state of mind: “Or I am mad, or else this is a dream” (IV.i.57). These references to insanity are significant. As he does with Antonio and Malvolio, Shakespeare suggests here that madness and the chaos associated with comedy are closely linked.

By Act IV, scene iii, however, Sebastian begins to come to terms with his situation. He decides that the sun that he sees is real, as are the air that he breathes and the pearl that Olivia has given him. “[T]hough ’tis wonder that enwraps me thus, / Yet ’tis not madness,” he decides (IV.iii.3–4). He even reasons out the situation with the beautiful woman who claims to love him. If Olivia were mad, he figures, surely her servants wouldn’t obey her—so she must be sane. All the same, he realizes, “There’s something in’t / That is deceivable” (IV.iii.20–21). He is right, of course; he just hasn’t figured out yet exactly what the deception is.

Meanwhile, issues of madness and identity are addressed in a different way in the dialogue between Feste and the unfortunate Malvolio. In this scene, Feste proves himself a master of disguise by imitating the curate’s voice and speech patterns. But there is something very strange in his disguise: there seems no reason for Feste to dress up in a priest’s robes if Malvolio, locked in the darkness as he is, cannot even see him. Again, as with Viola’s male clothes and Malvolio’s fantasies about wearing a nobleman’s garments, Shakespeare seems to suggest a link between garments and identity.To impersonate Sir Topas, Feste must dress like him, so closely are clothes and public personae bound together.

Feste also uses tactics of confusion on poor Malvolio, telling him outright lies to make him think his senses deceive him and, thus, trying to make Malvolio himself believe that he is insane. He adds the final insult after Malvolio angrily claims that he is as sane as Feste himself, telling Malvolio, “Then you are mad indeed, if you be no better in your wits than a fool” (IV.ii.82–83). Again, we are impressed with Feste’s cleverness; yet, as he torments Malvolio, we begin to wonder if he is employing his talents to a good end. The steward, whose earlier humiliation is perhaps well deserved, now seems a helpless victim. It is as if Malvolio, as the embodiment of order and sobriety, must be sacrificed so that the rest of the characters can indulge in the topsy-turvy spirit of the Feast of the Twelfth Night that suffuses the play.

Malvolio is hardly a tragic figure. After all, he is only being asked to endure a single night in darkness. But he earns our respect, nevertheless, as he stubbornly clings to his sanity, even in the face of Feste’s insistence that he is mad. Malvolio, perhaps more than anyone else in this frenetic, zany play, knows that he is sane, and he will not allow the madness swirling in the air of Olivia’s home to destroy his sense of his own sanity. One cannot help pitying him, in spite of his flaws. He seems to be punished for not being as mad as everyone else, more than he is for any real sin. He cries, “I say this house is as dark as ignorance, though ignorance were as dark as hell; and I say there was never man thus abused,” making the darkness of his prison a powerful symbol for the madness that seems to have taken over the world of the play (IV.ii.40–42). Malvolio is right—but being right avails him nothing. Twelfth Night is a play filled with absurdity and madcap fun, and Malvolio suffers his unhappy fate because he is unable to put his scruples, his puritanism, and his pride aside to join in the revelry.