Grave New Day (Jess Vandermire, Vampire Hunter Book 3)

Vampire and New York City Police Black Ops Captain Jess Vandermire is faced with the hardest Decision of her life—become human again and regain her soul or remain a vampire forever and fight an ancient evil that is a threat to every human on the planet. Ensnared in a plan that might go terribly wrong, she has little choice. As a human she can’t fight the ancient enemy. Then a mysterious stranger shows up and offers to help, and she’s not sure if he’s really on her side. She discovers her entire existence has been leading up to the challenge ahead. A challenge that has insurmountable odds, and if she doesn’t win, every human on the planet loses.