After an explosion, a new crime by an old murderer, and the sad passing of the founder of Norvelt, Pennsylvania, twelve-year-old Jack accompanies his slightly mental elderly mentor, Miss Volker, on a cross-country run as she pursues the oddest of outlaws.

It used to be the Thirteen-Story Treehouse, but now Andy and Terry, two creative boys who write books together, have added on and it is Twenty-Six Stories now, complete with a skate ramp, the Maze of Doom, an ice cream parlor, and even an antigravity chamber--plenty of space to have adventures in.