England, 1975. Neville Lark - 70's popinjay, relentless womanizer, connoisseur of baked goods, staunch supporter of public houses, investigator of the unusual and a deeply troubled northern soul - is drawn into a brutal murder case in the historic city of Chester. All signs point to an horrific incident from the past when an entire Roman garrison was slaughtered by supernatural forces, but who is resurrecting the ancient evil and why?