1814, London's Covent Garden entices rich and poor alike with a cocktail of gin, beer and sex. In the surrounding parishes a group of young men are found murdered, all of them wearing masks, all of them behind locked doors. Constable Charles Horton's investigation into these violent crimes begins at Thorpe Lee House in Surrey, where accusations of witchcraft have swept the village. What connects these broken London men, and a village awash with talk of burning witches?