1893: A train to the bustling industrial town of Pontypridd crashes, and in the chaos of the disaster a killer covers up a violent murder. Two years later Thomas Chard's arrival to take up his post as inspector in the burgeoning police force coincides with the grisly discovery of a body in the River Taff. Chard grapples with the demands of his new job – rudimentary Victorian police procedures, an authoritarian superintendent, and finding a murderer. His investigations lead him beyond respectable society, through the dark back streets of Pontypridd to a seamy world of money lenders, pick pockets, prostitutes and gamblers. As the number of suspects grows, each with their own secret to protect, Chard must disentangle the web of lies being spun around him in order to catch a killer.