Mrs Craydon was taken with the idea of digging up the history of the family. And once started she became more enchanted by the project. Even her husband George, having once seen the ancient photograph of a most attractive girl, long since dead, developed an interest in the family genealogy. The only snag was that even Great-Aunt Maud, the owner of the photograph, had no idea what had happened to the beautiful girl named Isabella. Apparently she had completely vanished and to the rest of the family had simply become The Unknown. Would the mystery ever be solved?