The Bailey School kids set out to discover whether Mr. Squash, the hairy, yellow-toothed giant they met while on a nature hike at Rudy Mountain is really Bigfoot.
After relating all of the horrible things the school custodian, Fester Smudge, is known to have done, a student whose locker won't open needs Mr. Smudge's help.
Kids are spreading rumors about what a horrible cook the new cafeteria lady is, so everyone is expecting the most disgusting lunch possible, but when they sit down to eat, they find a pleasant surprise.
Eleven-year-old Harriet keeps notes on her classmates and neighbors in a secret notebook, but when some of the students read the notebook, they seek revenge.