Hearts are fragile. For five hundred years Kassandra lived--and died. Now she's immortal, a vampire, and reunited with her soulmate, Rhys. They have all eternity to make up for lost time. Or they should. In the midst of a war against an insurgent organization, Rhys is accused of murder, and no one can prove his innocence. With Rhys imprisoned, awaiting dismemberment, Kassandra has only one option--train with Cade to learn how to fight this war, and develop skills that make her feel more like a monster than ever before. At night, Kassandra tracks down zombie-like failed vampires released to terrorize the humans. By day, she delves into the past, searching for answers to help free Rhys. But as she explores her past lives, Kassandra discovers evidence that she herself may be a traitor in the making. Anyone could be an enemy, old friends, or new. A single choice could define her in this new life: team player, or rogue element? Who can she trust when everyone is keeping secrets? One thing is clear: no one can survive without a heart, not even an immortal.