Fifteen years ago, 29 Barley Street in Menham, South London, became notorious as the scene of alleged poltergeist activity and then as a crime scene when young Holly Wasson hanged herself.

The shadow cast by the unhuman figure that tormented Holly has never entirely left Menham, or the gang of friends who were so affected by the strange and tragic events. The shadow looms large in the present when one of the group dies in a horrific circumstances.

Matt Hunter, former minister and now professor of sociology, is called in to advise the police on the possible ritualistic elements of the death. He can’t help being drawn into the potent mix of prayer walkers, spiritualists and talk of demons at large in the town, and drawn into the question: have forces beyond the grave been unleashed, or is a flesh-and-blood killer at work?