The Opal Deception is the fouth book in the Artemis Fowl series. It starts with Artemis trying to steal a prized painting and beign unsuccessful. He has been brain washed so he remembers nothing of the fairies. He meet Holly after an attempt on his life by Opal Koboi. Opal has already killed Jullies. Hoppy is on the run because the LEP's think she killed Jullies. Butler is left behind and he runs into Mulch Diggums who give him a disk that not only refreshes his memory but he immediately knows what kind of danger they are in. They rescue Holly and Artemis from Opal and figure out she plan to give up fairies to the human race. They immediately set out to stop it and they do get Holly's good name back nd get Opal. This is a really good book and I am sure you will enjoy it.