An unmarked grave. Two killers. And one woman who stands in their way... Forensic profiler Dr. Sophia Channing will be the star witness against Mason Vance, a brutal sexual sadist who kidnapped, raped and murdered six women. She can offer unique insight on the psychopath--she's his only witness that escaped alive. But the killer has other plans for her, even while behind bars. And when she's marked for assassination, Sophia realizes she's not finished with the violent psychopath either. DCI Agent Cam Prescott is providing Sophia protective custody while she continues her work with his team. Vance's accomplice is still on the loose. And as more bodies show up with the mark of the killers, Cam and Sophia begin to realize the terrifying breadth of the crimes. Their time is running out to catch the second killer. He's already picked out his next victim. And he's willing to go through Sophia to get her.