The Wolves of Willoughby Chase, by Joan Aiken

A children's book I read, not surprisingly, to my girls. Poor, orphan Sylvia Green is going to live with her rich cousin Bonnie. Bonnie's parents are about to leave on a long journey for the sake of Bonnie's mother's health. They have hired a distant relative to look after and teach the girls in their absence. But Miss Slighcarp, that distant relative, is not all that she seems to be. There follows a series of adventures for the two girls, which concludes happily. My girls were enthralled, and I was happy enough to comply with their repeated requests for more, and more, and yet more. They have commissioned me to search out other books by Joan Aiken.