Andy and Terry live in a 26-story treehouse. (It used to be 13 stories, but they've expanded.) It has a bumper car rink, a skate ramp, an antigravity chamber, an ice cream parlor with 78 flavors, and the Maze of Doom-a maze so complicated that nobody who has gone in has ever come out again. Well, not yet, anyway. This time, the two friends have a whole week to finish their next book, and Andy even knows what it should be about-the story of how he...