Criminal mastermind Artemis Fowl is so is his cunning enemy from Artemis Fowl: The Arctic Incident, Opal Koboi. At the start of the fourth adventure, Artemis has returned to his unlawful ways. He`s in Berlin, preparing to steal a famous impressionist painting from a German bank. He has no idea that his old rival, Opal, has escaped from prison by cloning herself. She`s left her double behind in jail and, now free, is exacting her revenge on all those who put her there, including Artemis.