John Marquez is back - but his mission is the same: shut down animal traffickers. Still attached to the California Fish & Game's Special Operations Unit, it's the open, unsolved investigations that now land on his desk.Then a tip call comes which reveals the location of a gun used to kill two young women camping along the Klamath River two years ago. At the same time, Marquez is on the hunt for a notorious animal trafficker known as Rider, who's rumoured to have a hideout in mountainous northern California. The subsequent discovery of thousands of invasive northern pike triggers a cascade of clues and questions that draws Marquez away from his pursuit of Rider. Or do they? Is there a connection?When a Siskiyou County investigator and an ambitious sheriff question Marquez's interest in the murders of the two women and his relentless presence in the remote northern county, the stakes rise ever higher - and the way forward is fraught with risk.