Artemis Fowl: The Atlantis Complex by Eoin Colfer

In this book Artemis Fowl finds he isn't himself--and not just because he has a plan to save the world. As Artemis suffers from the Atlantis Complex, Butler's sent on a wild goose chase to rescue his sister in Mexico, and a hardened criminal (who's hijacked a deep-space probe and sent it back to Earth to cause troubles) takes Artemis's meeting with Holly and Foaly as the excuse to start his escape plan, things look grim for our heroes. The book is a solid entry in the series; I found Artemis's alter ego, Orion, to be sort of funny. The plot moved a bit slowly for me, though.