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.
As he gets ready for a class trip, a boy worries about all the things that might go wrong--but they are nothing compared to what he experiences the day of the excursion.
On the first day of a new school year Mrs. Green's imagination runs wild as she thinks of all the horrible things she's heard about her new class, including that they've sent their previous three teachers into early retirement.