 At Larwood House, a boarding school where many of the children of executed witches are sent, a note claiming "Someone in this class is a witch" is found by a teacher.This launches an internal investigation of the more unpopular students at the school (Nan Pilgrim and Charles Morgan), who are gradually coming to terms with the fact that they are witches.Mayhem gradually ensues as magic is used to make birds appear in the classroom, to rain shoes, to curse a classmate into having his words always be true, and other pranks.