Leeds. December, 1916. Deputy Chief Constable Tom Harper is called out in the middle of the night when a huge explosion rips through a munitions factory supplying war materials, leaving death and destruction in its wake. A month later, matches and paper to start a fire are found in an army clothing depot. It's a chilling discovery: there's a saboteur running loose on the streets of Leeds. As so many give their lives in the trenches, Harper and his men are working harder than ever--and their investigation takes a dark twist with two shootings, at the local steelworks and a hospital. With his back against the wall and the war effort at stake, Harper can't afford to fail. But can he catch the traitor intent on bringing terror to Leeds?