On a cold winter's morning, the body of a young boy is discovered in Epping Forest. The body is pristine and peaceful, his head resting gently on a pillow, an angel pendant clenched in his small fist. It is a murder as carefully planned as it is brutal, and there's one person DI Bishop needs back on his team to help solve such a calculated crime.

Holly Wakefield, clinical psychologist for the Met Police, is better than anyone Bishop knows at getting inside the brains of psychopaths. But with the body count rising, it's going to take all Holly's strength to dive into the murky mind of someone who preys on young boys. And all Bishop's resolve to stop the serial killer before any more young angels are put to their rest.