Harry Houdini. A poison injector ring. Alcatraz. Mary Shelley's Frankenstein. What can they possibly have in common? Amy and Dan don't know, but fans of the 39 Clues series will soon find out. The first Cahill card series features 56 thoroughly intriguing evidence cards that kids need to hunt down the 39 Clues. The oversize cards (3.25 x 5) are loa...more