Valentine's Day and a dispute between rival gangs escalates into bloody violence. One teenage girl dead is left dead, another injured, and a police officer is caught in the crossfire. Detective Inspector Charlie Resnick, nearing retirement, is hauled back to the front line to help deal with the fallout. But when the dead girl's father seeks to lay the blame on DI Lynn Kellogg, his colleague and partner, Resnick finds the line between personal and professional dangerously blurred. Meanwhile, a murder case in which Kellogg was the chief investigating officer has stalled. One vital witness is threatened, and another is missing. But when SOCA  the Serious and Organised Crime Agency  start to show a keen interest in the case, believing there are links to international gun running and people trafficking, Lynn Kellogg finds herself drawn into a web of deceit and betrayal that puts both her and Resnick in mortal danger.