When Humphrey's teacher, Mrs Brisbane, doesn't come to school, he is unsqueakably worried. Then a supply teacher, the mysterious Mr E, arrives and everything changes. Humphrey has his paws full as he tries to gather clues to solve the mystery, and then, on Halloween, everything is revealed .

When Humphrey's teacher, Mrs Brisbane, doesn't come to school, he is unsqueakably worried. Then a supply teacher, the mysterious Mr E, arrives and everything changes. Humphrey has his paws full as he tries to gather clues to solve the mystery, and then, on Halloween, everything is revealed .