Simon, Mallory, and Jared Grace know that faeries are real-and that they aren't always the charming creatures portrayed in popular fairy tales. Ever since they discovered Arthur Spiderwick's Field Guide to the Fantastical World Around You, the Grace family has been surrounded by magical beings with decidedly hostile attitudes. They have a wounded griffin convalescing in the carriage house, a spiteful house boggart playing malicious tricks, and even weirder oddities lurking around practically every corner. Hoping to learn more about the book and its long-vanished author, the kids decide to consult their Great-Aunt Lucy, Arthur's daughter. She has been hospitalized ever since she was attacked by faerie beings who suspected that she knew where her father's book was hidden. She warns that the family will be in grave danger if they remain at Spiderwick Estate. When the siblings find an old map that leads into the elves' secret forest, their aunt's grim prediction seems all too plausible. The story ends with a cliff-hanger, to be continued in book four.