Artemis Fowl and the Opal Deception

Child genius Artemis Fowl is in terrible danger
He just can't remember why
Opal Koboi is back, and the power-crazed pixie wants revenge. Her to-do list:
- Frame Holly Short for murder
- Start a war between fairies and humans
- Kill anyone who's ever annoyed her (yes, this includes Artemis)
But knowledge of the fairies has been erased from Artemis's mind, and when you don't believe your arch-enemy exists, it can be quite tricky to defeat them.
It's unfortunate that Artemis's only hope is a farting dwarf. Enter Mulch Diggums . . .