The Forbidden Valley
Charlotte was worried to death about her cousin Phyllis, who seemed to have run away from home and left her children. It just didn't seem possible -- although Phyl's rather forbidding brother-in-law Edmund Leigh was only too ready to believe the worst of her.

So Charlotte set about solving the mystery, without letting Edmund realize who she was.

Hero: Edmund Leigh
Heroine: Charlotte de Lacey Smith