Artemis Fowl: The Opal Deception by Eoin Colfer
Evil pixie, Opal Koboi is back and she's more dangerous than ever. This time she doesn't just want power over the fairy People, this time she wants the lot. Everyone is under threat - humans and fairies alike. Captain Holly Short is the only fairy with a hope of stopping her, but as Holly knows, it takes one genius criminal mastermind to fight another. And the 14-year-old genius Holly is thinking of can't even remember that fairies exist. How is she going to convince Artemis Fowl to help her? Gold usually does the trick with that young man and this time is no different. Together Artemis, Holly, Mulch and Butler foil Opal Koboi's plans for world domination.