Many believe the Devil himself has entered Joseph Makepeace, the latest victim of a 'great fog,' that darkens the skies over England. When Joseph's children are found murdered, suspicions are confirmed: evil is abroad. Dr. Thomas Silkstone is not one to heed superstition. But when he arrives at the estate of widow Lady Lydia Farrell, he finds it's not just her livestock at risk. A shroud of mystery surrounds Lydia's lost child, a natural disaster fills the skies with smoke and ash.