Drury Lane, 1844. A robbery has been committed at a pawnbroker's, leaving three people dead. The man called in to investigate is Pyke, head of the Metropolitan Police's newly formed Detective Branch at Scotland Yard.Pyke must find the culprit and quickly, especially as the identity of one of the victims threatens to expose his own criminal past. A valuable religious artefact appears to have motivated the robbery but when the main suspect commits suicide in police custody, the investigation falters. Then the rector of a wealthy parish is brutally murdered and Pyke spots a connection. His suspicions lead him to a dissolute former Catholic priest, rumours of devil worship, and an old case that no one wants him to investigate. With time running out and the murderer threatening to kill again, Pyke must face up to forces within the police and the church who would prefer the secrets of the past to remain buried forever.