Set in 1848, Darkest Walk of Crime sees recently promoted Detective Mendick sent on his first case. Disturbing new evidence suggests the working class Chartist movement is seeking violent action after years of oppression and the defeat in Parliament of its plans for social and political reforms. With the spectre of civil war looming, Mendick goes undercover in the heart of Britain's industrial region - Manchester. He struggles with his loyalties when his sympathies are awoken by the plight of the working classes and the beautiful and enigmatic Chartist, Rachel Scott. But Mendick discovers there is more to the case than he has been led to believe. Soon he becomes wrapped up in a conspiracy that threatens to tear the country apart, and in unravelling this darkest walk of crime will take a perilous journey to the hub of British society.