Though happy living with her mother in London, twelve-year-old Susan is consumed by curiosity about the identity of her father and goes on a quest to look for him.
Young Mildred Hubble, an apprentice witch with a reputation for being the worst student at Miss Cackle's Academy for Witches, smuggles her cat Tabby on a class trip to Gloomy Cove with unexpected results.
Although her second year at Miss Cackle's Academy for Witches starts off better than her first, Mildred Hubble soon regains her reputation as the worst witch in the school when she and Ethel Hallow resume feuding.