Spiderwick Chronicles - Lucinda's Secret

Lucinda's Secret was published on October 1, 2003. The novel opens upon and argument among the Grace children on whether or not to destroy the Field Guide, Jared alone insisting that they keep it. They eventually agree to consult their Great-Aunt Lucinda, who is now staying in a psychiatric hospital and is the only person whom they know to have been in contact with Arthur Spiderwick, who was her father. When they ask her about Arthur, it is revealed that the last she saw him was one day when she was a little girl, on which Arthur had set out from the house on foot and never returned. She is horrified that the Grace family is staying at the Estate, which she says is not safe, and even more worried when she hears that they have the guide, believing her father to have taken it with him when he disappeared. However, when Jared takes the book from his backpack to show her, it has been replaced with another book, assumedly by Thimbletack. Once home, the Grace children decide to find out what happened to their great uncle, and set out from the Estate with a map of the area on which is written- "September 14th. Five O'clock. Bring the remains of the book." On their journey they meet a Phooka, a creature that talks only in riddles. They finally reach a forest grove inhabited by elves, who threaten to trap one of the children there unless the guide is given to them. The children escape, however, promising to bring the guide as soon as they can. On passing by the Phooka again, one of his riddles leads them to think that Arthur is still alive, but imprisoned in Faerie with the elves.