Best-selling author Alexander McCall Smith enthralls children with Akimbo adventures, Harriet Bean mysteries, and Max & Maddy detective tales like Max & Maddy and the Chocolate Money Mystery. Wealthy adventurer Harry Helium hires Max and Maddy Twist-world Clue champions and children of private detective legends-to stop a saboteur from affecting a New York to Vancouver hot-air balloon race. But as the race begins and dangerous incidents grow worse, the mysterious culprit lurks closer than anyone realizes.