Katie Martin wasn’t looking for a mystery… but when she discovers a hidden switch in her school library, it moves an entire bookcase, revealing a secret world waiting to be uncovered. With her friends Ben and Ella, Katie forms The Snoops — a team of ordinary kids with a knack for noticing what others miss. Packed with puzzles, daring teamwork, and hidden clues, this thrilling mystery is the first in A. J. Bolster’s Snoops Mystery Adventures: Secrets of the School."