The main female protagonist of Diana Wynne Jones’s Howl’s Moving Castle is Sophie Hatter. She is the eldest of three sisters in Market Chipping, a town in the magical kingdom of Ingary.
At the beginning of the novel, Sophie is resigned to running her family’s hat shop because fairy-tale convention says the eldest of three children is least likely to succeed. Her life changes when the Witch of the Waste mistakes her for her sister Lettie and curses her with the body of an old woman.
Sophie then leaves home and becomes the cleaning woman in the moving castle belonging to the wizard Howl. Her practical courage, ability to speak life into objects, and growing confidence make her the story’s driving character. Howl, Calcifer, Lettie, and Martha are important figures, but they are not the main female protagonist.