When Maddy Miller gets her long-awaited heart transplant, she thinks her life has been saved. But the heart came from a vampire, and he wants it back. The heart of a vampire is a powerful and valuable thing. From rabid dog-monsters to mysterious con-men and clandestine government agencies, there's no shortage of people who are after the heart that now beats in Maddy's chest. As people start dying all around her, Maddy begins to realize that she's in mortal danger. A mysterious figure arrives on the scene, offering to save her, but can even he be trusted? Maddy must make a decision fast, and the consequences could change the world forever. Will Maddy get to keep her heart? Who will win the struggle to win her trust? Why did one of the world's most powerful vampires lose his heart in the first place? And what dark forces are working behind the scenes to change the fate of the entire world?