The House of Puzzles

A mysterious coded message. A search for a fabled perpetual motion machine. A terrifying horse ride. And a night in the exclusive Billionaires' Club House of Puzzles. If Gerald thought his term in a Scottish Highlands school camp was going to be all snow-covered heather and tartan rugs he couldn't have been more wrong. With Professor McElderry in the clutches of Gerald's nemesis, Sir Mason Green, and a seemingly impossible task required to save his life, Gerald, Ruby, Sam and Felicity face their greatest challenge yet.