Seen Yentl? Don't bother reading this, then. That's basically this, but with songs. Oh, wait. This has songs, too. Nobody ever sings them, though.
The story begins with this guy brooding about how he's in love. He's a duke, so people think he's important, so we have to listen to him. It's actually supposed to be a song, but I've never seen anybody present it that way.
At the same time Mr Duke is carrying on, Viola is being shipwrecked. She's lost pretty much everything, and she's all alone, poor thing. So, since she's a woman and has pretty much nothing (keeping in mind that Shakespeare wrote this during Shakespeare's time) she decides to dress up as a boy and serve this some duke guy so that she can at least earn enough money to get home. Since her brother is dead, she figures, hey, I might as well pose as him. Makes her story more plausible or something.
Well, anyway, we realize in the next scene that this guy Viola plans on working for is the jerk was saw carrying on in the first scene. Blah. He sends Viola to court Olivia for him. Olivia's upset and mourning for her brother, and is ornery and stuff. Viola goes, but she's sad that she has to go, because she's in love with the Duke herself. So she goes, blah blah... and Olivia falls in love with her. Remember, she's (meaning Viola) is dressed as a boy at this point.
Then, there's a bit of a cut scene with Sir Toby, Sir Andrew, Feste the Clown and Maria. It isn't really important. Just humorous side action. If you're taking a test on it, though, I suggest you read it.
Aren't I wicked?
Basically, Malvolio (Olivia's chamberlin, or something like that) is mean to them, so they want to make him look like an idiot.
Viola and the duke have a poignant conversation about love. Aw. Malvolio falls victim to a trap the Sirs set up for him. Now, he's going to dress in yellow, cross-gartered. Ooh. Freaky. I think Britney Spears wore the same thing at her last concert, so now thousands of eight year old children look like Olivia's balding chamberlin guy. Well, whatever. I went on a tangent there, didn't I.
Viola tries to convince Olivia (again) not to love her. Doesn't work.
Man, the parts with the sirs are long, boring and drunken.
So then in comes Malvolio looking like Britney Spears, so Olivia promptly has him put in a cave or a mental institution or something. Because he's crazy, see. And Sir Andrew and Sir Toby aren't. Mmhmm.
Antonio shows up around then. Good for him.
Then Sebastian shows up! Yay! He isn't dead after all! But he does end up marrying Olivia. Of course, then, after a bit of hilarity, the situation is resolved. Malvolio comes back, the Sirs reveal the trick, everybody laughs, Viola marries the dude, ta da, the end. Hooray.
Suggested Listening: Any song from the play you can come up with, "Being for the Benefit of Mr. Kite - the Beatles, Irish Drinking Songs.