Three times the mystery. The Challenge Trilogy is a Sherlock Holmes inspired collection of brain teasers. From Baker Street to your living room, you can now use your powers of deduction and reasoning to solve over 150 riddles, puzzles and absolute enigmas! Grab your magnifying glass and join in the Holmes fun!This trilogy includes: The Case of the Double Agent, The Case of the Cryptic Clue and The Case of the Curious Conundrums.