The children of murder victims are targeted by a copycat killer in this detective thriller by "the new-wave leader of crime fiction" (Lee Child).

Detective Tom Thorne specializes in solving the London Police Department's most difficult murder cases. When he's called into what seems like an ordinary domestic crime scene, he thinks he's caught a break. A woman has been murdered by someone she knows. Thorne plans to question the husband, arrest him, and get back to his own deteriorating personal life. But something doesn't fit . . .

A sliver of X-ray was found in the victim's fist. When bits of the same X-Ray are found at other crime scenes around the city, Thorne realizes he has a grisly puzzle to solve. As the pieces begin to form a picture, a terrifying truth is revealed: the murderer is following in the footsteps of infamous serial killer Raymond Garvey—hunting the children of Raymond's victims.

Now, as Thorne attempts to protect those still alive, he gets dangerously close to one of the most twisted killers he has ever hunted.