The Mystery of Mrs. Blencarrow - Margaret O. Oliphant

The location is the English Lake District and the characters very ordinary people. Mrs. Blencarrow is a widow with five children and control of her late husband's small estate. She is eminently respectable and is involved with the usual round of tea and dinner parties as expected in a quiet town. She is unremarkable, apart from her disdain for scandal, or even gossip of any kind. Imagine the surprise when a stranger describes her as "a woman with a history"? That can only mean a disreputable past or even a scandal, but as she has lived in the community for 18 years, without a hint, what could it possibly be?