"Andy and Terry are once again inviting readers to come hang out with them in their astonishing 39-story treehouse (it used to be 13 stories, then 26 stories, but they keep expanding). And this year they will have even more time to jump on the world's highest trampoline, toast marshmallows in an active volcano, swim in the chocolate waterfall, pet baby dinosaurs, and go head-to-trunk with the Trunkinator, since Terry has created the greatest invention...

Andy and Terry's 13-storey treehouse is the most amazing treehouse in the world! It's got a bowling alley, a see-through swimming pool, a tank full of man-eating sharks, a giant catapult, a secret underground laboratory and a marshmallow machine that follows you around and shoots marshmallows into your mouth whenever you're hungry. Well, what are you waiting for? Come on up!