Miss Viola Swamp is the meanest, most horrifying substitute teacher a child could ever imagine. She takes over Miss Nelson's rowdy, spitball-throwing elementary-school class in Harry Allard's children's book, Miss Nelson Is Missing, and forces the children to (gulp!) be quiet and do arithmetic. She also cancels story hour and assigns them an insurmountable amount of homework. Oh, and she's also a witch. Miss Swamp may be a terrifying teacher, but when Miss Nelson finally returns to class, she discovers that her students no longer misbehave.