John River is a respected police officer haunted by the murder victims whose secrets he must uncover. Struggling to come to terms with the recent loss of a close colleague, River chases a potential suspect across London, with tragic consequences. In his fragile mental state, he comes under increasing pressure both from the press and within the police force as calls for his dismissal grow.

Still wracked with grief over the death of his friend and partner Jackie 'Stevie' Stevenson, River and his colleagues must attend her wake. There he is surprised to come across her brother Jimmy - recently released after serving sixteen years for a brutal murder, in which Stevie's own evidence was key. River reaches breaking point as he begins to suspect that Christopher Riley, the man he chased to his death, was innocent.

With his career and access to the Stevie case resting on the outcome of his psychiatric report, River must keep his investigations to himself, sending tensions high with his new partner Ira who fears being dragged down by River’s instability, and with Chrissie, who needs River working on his own caseload, most pressingly investigating a suspicious workplace accident that has left a foreman fighting for his life. But River’s mind is elsewhere as the discovery of Stevie’s second phone forces him to reassess how well he knew his best friend and colleague.

River’s state of mind reaches crisis point as the team launch a manhunt to find Haider, the man who owned the car used in her murder. Was Stevie really as lonely as River thought? As he tries to survive the torment of Haider’s uncontrollable manifest, a concerned Rosa encourages River to pay her back for the positive psychiatric report by attending a group of like minded troubled souls, with mixed results.

Following the murder in the public library, River and Ira must track down the killer. Their journey takes them deep into the world of the illegal immigrant community of London, a world of international hostels and immigration lawyers, they begin to get a sense of what it was that Stevie might have been unravelling before she died. Was it these investigations she was punished for? And as River finds himself back at the hearing voices group, an unfortunate contribution leads to River being drawn closer to Rosa, his colleague and counsellor.

River is convinced that Stevie’s investigation into the exploitation of illegal immigrants holds the key to her murder. Further questioning of someone close to the team reveals a system of immigration cases that could lead into some very unexpected places. When a common link to certain businesses is found, it all starts to fall into place for River, with unfortunate repercussions.