From what I've gathered after seeing the first episode (And I don't remember the names):
A poor girl who looks like a boy goes to an expensive, high class school due to her excellent grades. Unfortunately while wandering around she stumbles upon the "Hosting Club." While she's there, she accidently destroys a vaulable vase. In order to pay off her debt, the host club has her (though thinking she's a he) join their club and work it off.
Mostly a Shoujo storyline with some great humor in it. I highly recommend it.