When Kate Marshall finds the body of a young man floating in the Shadow Sands reservoir, the authorities label it a tragic accident.

But the details don't add up: why was he there in the middle of the night? If he was such a strong swimmer, how did he drown? As Kate and her assistant Tristan Harper follow the evidence, they make a far darker discovery...

This is only the latest victim in a series of bloody murders dating back decades. A mythic serial killer is said to hide in the rolling fog, abducting his victims like a phantom. And when another woman is taken, Kate and Tristan have a matter of days to save her from meeting the same fate.