Dr. Elise Hanover quite literally lives for her job—since quitting would mean meeting a silver bullet with her name on it. She works alone, struggling to unlock the mysteries of an affliction that should only exist in nightmares. But Elise knows from personal experience just how real it is. Because the first time its deadly power pulsed through her veins was the last time she saw the love of her life. Until now...

The surprise visit from FBI agent Nic Franklin is merely the first in a series of shocks. After her lab is firebombed and her most bloodthirsty test subject escapes, Elise and Nic have no choice but to join forces. Unfortunately, the situation in remote Fairhaven, Wisconsin is far from safe: Nic has too many questions about Elise's work and why she deserted him years ago; townsfolk are disappearing, and Elise feels her own condition intensifying in ways as terrifying and exhilarating as her rekindled attraction to Nic. Now, as a shadowy evil closes in, it’s becoming all too clear that Elise is the only one who can stop it—if it doesn't stop her first...