Orsino approaches Olivia’s house, accompanied by Viola (still disguised as Cesario) and his men. The Illyrian law officers come in looking for Orsino, dragging Antonio. Orsino, who fought against Antonio long ago, recognizes him as an honorable enemy. He asks Antonio what caused him to come into Orsino’s territory, where Antonio knew he would be in danger. Antonio responds by telling the story of how he rescued, befriended, and protected Sebastian, traveling with him to this hostile land. He lashes out at Cesario, whom he continues to mistake for Sebastian, claiming that Sebastian has stolen his purse and denied knowing him. Viola and Orsino are both bewildered, for Viola truly does not know Antonio.

Olivia enters and speaks to Cesario, she too believing him to be Sebastian, whom she has just married (at the end of Act IV, scene iii). Orsino, angry at Cesario’s apparent betrayal of him, threatens to carry Cesario off and kill him. Viola, resigned, prepares to go with Orsino to her death and says that she loves only him. Olivia is shocked, believing that her new spouse is betraying her. She calls in the priest, who, thinking that the young man in front of him is Sebastian, testifies that he has just married Olivia to the young man. Orsino orders Olivia and Cesario to leave together and never to appear in his sight again.

Suddenly, Sir Andrew enters, injured and calling for a doctor. He says that he and Sir Toby have just been in a fight with Orsino’s servant, Cesario. Seeing Cesario, Sir Andrew accuses him of the attack, but the confused Viola answers that she is not responsible. Olivia orders Sir Andrew and Sir Toby away for medical attention.

Finally, Sebastian appears, apologizing to Olivia for having beaten up Sir Toby and Sir Andrew. Recognizing Antonio, and not yet seeing his sister, Sebastian cries out joyfully how glad he is to see him. Dazed, all the others stare at Sebastian and Viola, who finally see one another. They interrogate one another with a barrage of questions about their birth and family history. Finally, they believe that they have each found their lost sibling. Viola excitedly tells Sebastian to wait until she has put her woman’s clothing back on—and everyone suddenly realizes that Cesario is really a woman.

Orsino, realizing that Olivia has married Sebastian, doesn’t seem terribly unhappy at losing her. Turning back to Viola, he reminds her that, disguised as a boy, she has often vowed her love to him. Viola reaffirms her love, and Orsino asks to see her in female garb. She tells him that her clothes were hidden with a sea captain, who now has taken service with Malvolio. Suddenly, everybody remembers what happened to Malvolio. Feste and Fabian come in with Malvolio’s letter, delivered from his cell. At Olivia’s order, Feste reads it aloud. Malvolio writes that the letter seemingly written to him by Olivia will explain his behavior and prove he is not insane.

Realizing that Malvolio’s writing does not seem like that of a crazy man, Olivia orders that he be brought to them. Malvolio is brought in, and he angrily gives Olivia the letter that Maria forged, demanding to know why he has been so ill treated. Olivia, recognizing Maria’s handwriting, denies having written it but understands what must have happened. Fabian interrupts to explain to everyone how—and why—the trick was played. He mentions in passing that Sir Toby has just married Maria. Malvolio, still furious, vows revenge and leaves abruptly. Orsino sends someone after Malvolio to make peace and find Viola’s female garments. He then announces that the double wedding will be celebrated shortly. Everyone exits except Feste, who sings one last song, an oddly mournful melody about growing up and growing old, and the play ends.

This long scene concludes the action of the play. A few at a time, the play’s main characters enter until they are all in the same place at the same time, and the various confusions and deceptions can finally be resolved. Of course, the ultimate climax is the reunion of Sebastian and Viola—their meeting unravels the major deceptions and conflicts of the play.

The moment before the climax, significantly, is the most complicated moment in the entire play for Viola, at least in terms of how everyone understands her identity. Just before Sebastian’s entrance, Viola, in her disguise as Cesario, is surrounded by many people, each of whom has a different idea of who she is and none of whom knows who she actually is. Sebastian’s entrance at this point effectively saves Viola from her identity crisis. We might think of the scene as showing Sebastian taking over the aspects of Viola’s disguise that she no longer needs to wear. It is Sebastian whom Antonio has really been seeking, Sebastian who has really married Olivia, and, in the end, Sebastian who is actually male. Thanks to her brother’s assumption of these roles, Viola is free to cast off her masculine disguise. First she casts it off through speech, as she lets everyone know that she is really a woman, and then through deed, as she talks about putting back on her women’s clothing, or “maiden weeds” (V.i.248).

But even once the truth about Viola’s womanhood comes out, the uncertainty that her disguise has raised remains. For instance, Orsino’s declaration of love to Viola is strangely phrased. Continuing to address Viola as if she were male, he says, “Boy, thou hast said to me a thousand times / Thou never shouldst love woman like to me” (V.i.260–261). Similarly, in his final lines Orsino declares,

Orsino continues to address his future wife by her assumed male name, which hints at his ongoing attachment to Viola’s masculine potential. Though he knows Viola is a woman, he continues to recognize Cesario as a legitimate identity for Viola. His statement that in female garb Viola will be his queen does not make it clear that he is asking Viola to renounce her assumed male identity forever; nor is it clear whether Orsino is truly in love with Cesario or Viola.

Equally puzzling, but in a different way, is Orsino’s earlier threat to kill Cesario when he thinks his servant has betrayed him. “I’ll sacrifice the lamb that I do love,” he says, and Viola acquiesces meekly (V.i.128). “And I, most jocund, apt, and willingly, / To do you rest, a thousand deaths would die,” she declaims (V.i.130–131). These bizarre speeches—articulating Orsino’s strange violence and Viola’s apparent death wish—recede into the background amid the general rejoicing that follows, but they leave critics baffled. Perhaps Shakespeare is suggesting that love is so close to madness that both Orsino and Viola can easily tip over the edge into blood-drenched insanity, where one lover becomes a killer and the other a sacrificial lamb.

Meanwhile, the general happiness that prevails is marred by the reemergence of Malvolio from his dark prison. When the trick is revealed, no one else seems to be quite as upset about it as the steward. “Alas, poor fool, how have they baffled thee!” Olivia says to him, calling the resolutely unfoolish Malvolio a “fool” (V.i.358). This barb, at once, adds insult to injury and shows how the spirit of the play has upended even the steadfast, puritanical steward. The unamused Malvolio’s parting remark—“I’ll be revenged on the whole pack of you”—sounds a jarring note in the supposedly tranquil, joyful concluding scene (V.i.365). Malvolio’s anger injects a hint of pathos or realism into the otherwise idyllic ending: someone must suffer while everyone else is happy. Antonio is likewise sacrificed to the anarchic spirit of the play, although less noticeably: his homosexual ardor for Sebastian must go unsatisfied in a play where heterosexual marriage is the logical endpoint.

For those who feel a sense of disquiet and ambivalence amid the joy of the conclusion, Feste’s closing song seems to provide some support. The song is the last of many musical numbers in the play, and it is also one of the most melancholy, recounting a story of growing up to discover the harshness and unkindness of life. Comedy and romantic bliss triumph in Twelfth Night, but through characters like Malvolio and Feste, Shakespeare leaves us with a feeling of unease. Like the feast that gives the play its name, Twelfth Night is festive and joyful—but all feast days must come to an end, the concluding song suggests, and give way to the “wind and the rain” of life (V.i.387).