In December 1811, two horrific murders shocked London’s East End district of Wapping. The cloth merchant Thomas Marr and his family are found mutilated in their home: father, mother, shop-boy and baby. Mere days later, the Williamsons, proprietors of the King’s Head pub, suffer the same fate. Known as the Ratcliffe Highway Murders, these events really happened, as did the clumsy investigation by the Shadwell magistrates that followed. Lloyd Shepherd makes this the basis of his eerily compelling novel: an early police procedural mixed with an ominous ancient evil. As the people of Wapping clamour for justice, Constable Charles Horton of the River Thames Police Office – under the aegis of his ex-navy boss, John Harriott – embarks on an investigation that, before it ends, will have ushered him into the very darkest places of the human soul.