Mr. Mystery Invisible Ink Trivia & Game Books Gift Set Bundle (4 Pack) All 4 Mr. Mystery Sets Included for Hours of Fun! Use your Invisible Ink pen to uncover the truth and solve the mysteries. 192 Pages of Fun! (48 pages in each set) Here are just some of the games you will find inside this book, decode the cryptograms, decipher Krazygrams, and nab the crook in jailbreak Ages 7+