Artemis Fowl and the Lost Colony

Centuries ago, a great battle forced the fairy world underground, leaving one demon colony trapped in Limbo. Now, as their time spell unravels, these demons are returning to Earth, threatening to expose all magical creatures. The fairies turn to the brilliant young mastermind, Artemis Fowl, to decipher complex temporal equations and prevent catastrophe. However, Artemis soon discovers he's not the only genius who has cracked the secrets of the fairy world, facing an unexpected rival in a twelve-year-old girl.