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

...

Andy and Terry must get past their differences to save their story ideas from a herd of spy cows.

"Andy and Terry live in a 143-story treehouse. (It used to be a 130-story treehouse, but they built another thirteen stories.) Andy's been a bit stressed out lately, so Terry decides the perfect way to relax would be to head up to their new camping ground level for a much-needed vacation. But it turns out to be not quite as relaxing as planned. Terry forgets to pack the tent and the food, their attempt at fishing ends in disaster, the spooky campfire...

Dory, a highly imaginative youngest child, makes a new friend at school but her brother and sister are sure Rosabelle is imaginary, just like all of Dory's other friends.

When their over-the-top ideas expand their amazing treehouse to include a giant submarine sandwich shop and a human pinball machine, Andy and Terry find themselves babysitting Mr. Big Nose's three troublesome grandkids.

After Nobody destroys the connection between fictional and nonfictional worlds, causing nonfictional people to lose their imaginations, Owen and Bethany must risk everything to save multiple realities.

Fourth-grader Frankie Piccolini's vivid imagination does not help him advance in rank with the rest of his Possum Scout troop, but winning the Pine Run 3000 model car race would give him the points he needs.

Two little girls who love to draw witches build an elaborate world around the imaginary Old Witch and her family.

When young Boo is followed home by a dinosaur that only she can see, it causes a bit of trouble for her older brother, Sammy.