Scene i: The setting is the foreign land of Illyria, and the play opens at the palace of the youthful Duke Orsino as he speaks in lyrical but melancholy verse about his love for a beautiful countess, Olivia. A messenger arrives with bad news for the Duke: Olivia has rejected his marriage proposal, saying that she wishes to enter into a period of seclusion following the death of her brother. This vow only adds to the Duke's admiration of Olivia and her devotion increases his ardor.
Scene ii: On the seacoast of Illyria, we see the play's chief protagonist, Viola with a sea captain and learn that the ship that they were sailing on has been wrecked. Sebastian, Viola's twin brother, was aboard the same vessel. Although his fate is still unknown, the captain tells Viola that Sebastian may also have been rescued. The story of Duke Orsino's unrequited love for Olivia is related to Viola by the captain.
She then decides to join the Duke's court disguised as a young man.
Scene iii: At the palatial home of the countess Olivia, we are introduced to her uncle, Sir Toby Belch, and to one of her servants, Maria. Sir Toby complains about his niece's reclusiveness. Uncle Toby's concern here is not Olivia's withdrawal, but its effect on his plan to marry his lovely niece to one of his rich and foppish friends, Sir Andrew Aguecheck. Maria says that Toby and Sir Andrew should tone down their hard-drinking merriment, of which Olivia disapproves. Having made no headway in his suit for Olivia's affection, Sir Andrew enters and says that he will leave the house because the Duke is actively courting her, but Sir Toby assures him that Olivia has rejected the Duke's romantic overtures.
Scene iv: The act...