The Brittany Stones — Lynna Cooper

In the swirling London fog, Adele Putnam witnessed a very real murder -- but when the killer and his victim later vanished, she began to doubt her senses. Her brother Michael told her to forget the incident and to accompany him to Brittany, where he intended to study the ancient monoliths of Carnac, similiar to Stonehenge.

Adele was happy to go. Not only would she aid Michael in writing his book, but she could visit her girlhood friend Lysette, who had married the Count de Kerceval. But to her horror, she found that Lysette was dead, and the handsome grieving husband was none other than the man she'd seen in the London fog....