The scene opens on the street in front of Olivia's house. Sebastian and Feste are talking, and we realize that Feste has mistaken Sebastian for Cesario. Feste insists that his mistress has sent Feste to him, meaning Cesario. Sebastian is annoyed at the jester's persistence; "Thou art a foolish fellow," he says, and gives him a generous tip to send him on his way — or else he will give Feste "worse payment," meaning a kick in the rump if he doesn't leave him in peace.
Sir Andrew, Sir Toby, and Fabian enter, and Sir Andrew assumes that Sebastian is the "cowardly" Cesario; Sir Andrew strikes him, whereupon Sebastian promptly beats Sir Andrew, asking, "Are all the people mad?" Feste says that he is going to report to Olivia all that has happened, and she will not be pleased to learn that her favorite suitor, the reluctant Cesario, has quarreled with Olivia's uncle and with Sir Andrew. Sir Toby, meanwhile, decides that it is time for him to act; he grabs the young upstart (Sebastian) by the hand in an effort to save Sir Andrew from greater injury.
Olivia arrives, assumes that Sebastian is Cesario, and pleads with him to go into the house. She severely reprimands Sir Toby and sends him away, out of her sight, and he exits, taking the other two with him. She apologizes for the "pranks of [these] ruffians," and while she is talking, Sebastian is speechless. He cannot believe what is happening: he is being wooed in the most ardent of terms by a beautiful young countess; if this be a dream, he says, "let fancy still my sense in Lethe . . . let me sleep." Olivia is insistent: "Come, I prithee," she says, and begs him to marry her. Without hesitation, Sebastian accepts: "Madame, I will," he says, and off they dash to look for a priest to perform the ceremony.
