Peter Grant, having become the first English apprentice wizard in fifty years, must immediately deal with two different but ultimately inter-related cases. In one he must find what is possessing ordinary people and turning them into vicious killers, and in the second he must broker a peace between the two warring gods of the River Thames. 

The graphic novel is based on the bestselling novel "Rivers of London" published by Gollancz in 2011 and recently re-released by Orion in paperback.