Use the decoder wheel to solve the mystery . . . then turn the page for a whole new challenge! This exciting spy activity book has 18 pages of codes to crack and whodunits to solve. A few turns of the included decoder wheel bound right into the book and visible from every page will help young detectives complete each challenge as they put their deductive skills to the test! To uncover even more case-busting clues, sneaky double agents, and hidden treasure, a magic-reveal pen is included, giving every page plenty of play value. It all stores neatly within the tab-close covers perfect for spies on the go.