Andy and Terry live in a treehouse. But it's not just any old treehouse, it's the most amazing treehouse in the world! This treehouse has thirteen stories, a bowling alley, a see-through swimming pool, a secret underground laboratory, and a marshmallow machine that follows them around and automatically shoots marshmallows into their mouths whenever they are hungry. Life would be perfect for Andy and Terry if it wasn't for the fact that they have to write their next book.