Lucinda's Secret

The Grace children Jared, Simon, and Mallory face increasingly dangerous encounters with fantastical creatures, including goblins, a bridge troll, and the house boggart Thimbletack. With more creatures from Arthur Spiderwick's Field Guide appearing, the children turn to their Great-Aunt Lucinda for help. Simon has hidden an injured griffin in the carriage house while the children rely on the Field Guide for protection against the magical threats surrounding them. This is the third book in the Spiderwick Chronicles series, written by Tony DiTerlizzi and Holly Black.