Doug thought he knew everything about his best friend, Harry . . . until he discovers that Harry has a secret hideout in the woods. Unfortunately, Harry can't keep his hideout under wraps for much longer, because it is going to be replaced by a big apartment building - unless the kids in Room 3B can save it. They want to turn the land into a nature center after seeing its beautiful wildflowers. But can Harry convince the principal? Or will his horrible fear come true: losing his hideout forever?