- Inside Olivia's house, Maria makes Feste wear a disguise and pretend he's a clergyman named Sir Topas, who has come to visit Malvolio. (Malvolio is now locked up like a prisoner in a dark room in Olivia's house. Remember, Olivia told Maria, Toby, and crew to take care of him when it seemed that Malvolio had gone mad. Maria and Toby are pretending to believe that Malvolio is "possessed" and needs an exorcism.)
- Feste makes a crack about how he's not the first fraud to wear a clergyman's outfit. Then he approaches Malvolio and pretends to be "Sir Topas."
- "Sir Topas" says that he's come to visit "Malvolio the lunatic." Malvolio begs "Sir Topas" to fetch Olivia so the whole mess can be straightened out.
- "Sir Topas" says Malvolio's been possessed by a sex-crazed devil and proceeds with the mock exorcism.
- Malvolio complains about the darkness of the room but "Sir Topas" insists it's perfectly well lit. It has bay windows that are as clear as a stone wall and windows facing north and south that are blackened. So...really, Feste is agreeing that it's dark, but he's talking in riddles and saying that Malvolio thinks it's dark because he's mad.
- Malvolio insists he's sane and tells the fool to ask him a common sense question to prove it. The fool asks him about Pythagoras, and Malvolio answers, correctly, that Pythagoras believed in reincarnation, a philosophy Malvolio doesn't agree with.
- The fool turns Malvolio's views against him and steps out.
- Maria comments that Feste could have pulled off the prank without the physical costume since the whole joke depends more on Feste's ability to disguise his voice, not his looks.
- Toby tells Feste to go back to Malvolio and play himself and Sir Topas. Feste obliges.
- Feste returns to Malvolio and sings one of his catchy little songs. Malvolio recognizes Feste's voice and begs the Fool to fetch him a pen, paper, and a light so he can write a letter that will exonerate him.
- Feste treats Malvolio like a madman and Malvolio tries to explain that Toby and crew have locked him up and sent an exorcist in order to make him go crazy.
- Feste uses his "Sir Topas" voice and advises Malvolio to get some sleep. Then Feste pretends to have a conversation with Sir Topas about Malvolio's condition.
- Malvolio begs Feste for pen and paper again and claims he is as sane as anybody else in Illyria. Feste asks him if he's faking the whole thing and finally promises to fetch some paper and a pen.
- Feste skips off singing while Malvolio remains locked up.