Who wouldn't want to live in a treehouse? Especially a 13-storey treehouse that has a bowling alley, a see-through swimming pool, a tank full of sharks, a library full of comics, a secret underground laboratory, a games room, self-making beds, vines you can swing on, a vegetable vaporiser and a marshmallow machine that follows you around and automatically shoots your favourite flavoured marshmallows into your mouth whenever it discerns you're hungry. Two new characters - Andy and Terry - live here, make books together, and have a series of completely nutty adventures. Because: ANYTHING can happen in a 13-storey treehouse.