From the Publisher:
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 loaded with top-secret Cahill information and intriguing puzzles that unlock the family's secrets. Each pack contains 16 randomly assorted cards, with at least one rare or ultra-rare card per pack.
Who will be first to solve the mystery of the Cahill family? Who will be the first to win the $100,000 in real prizes? THE 39 CLUES is a ten-book series about a vast historical puzzle that includes Harry Houdini, Napoleon, and more. The books set the stage for the adventure, but kids will need to buy CARD PACK 1, because each card offers a clue that can help lead them towards actual prizes.