When the mutilated body of a young woman is discovered in the Santa Monica Mountains, LAPD Detective Jessica Allen knows this isn't the work of a first-time killer. She's seen this MO before -- two and a half years ago on the other side of the country. Allen begins to dig deeper and soon uncovers a terrifying truth. A sadistic serial killer has been operating undetected for the past decade, preying on lone female drivers who have broken down. The press dub the killer 'the Samaritan', but with no leads and a killer who leaves no traces, the police investigation quickly grinds to a halt. That's when Carter Blake shows up to volunteer his services. He's a skilled manhunter with an uncanny ability to predict the Samaritan's next moves. At first, Allen and her colleagues are suspicious. After all, their new ally shares some uncomfortable similarities to the man they're tracking. But as the Samaritan takes his slaughter to the next level, Blake is forced to reveal that the similarities between the two men are closer than even Allen suspects. With time running out and an opponent who knows all of his tricks, Blake must find a way to stop the Samaritan... even if it means bringing his own past crashing down on top of him.