The fog of the title is London fog, rolling in to make everything murky and even more mysterious than it already is.
Saved by a stranger she believes is an anger when her parents are killed in a train wreck, Felicia Lamb grows up believing in the supernatural and the Afterlife. She comes under the influence of Mr. Newcastle, a medium, in reality the vampire, still watching over her.
Felicia has things other than a vampire to worry about however, thought she's unaware, for her fiance, Reginald Callendar is a gambler and a drunkard, left destitute by his wealthy uncles death and determined to marry Felicia to gain her fortune so he can spend it. He comes up against Newcastle, seeing in the medium a rival for Felicia's wealth if nor her love.
What follows is a Victorian-set gothic novel with a great deal of description, notations about the life of the times, and a chilling atmosphere enhanced by that creeping yellow fog. The ending was a surprise.
I didn't realize this was part of a series and I wish now I had a few of the other entries to read also.
This novel was purchased by the reviewer and no remuneration was involved in the writing of this review.