State pathologist Terry O'Brien is about to take on her toughest role yet. Tasked with leading the Open Case Review Unit, her usual post-mortem work has been extended to cold-case investigation into unsolved suspicious deaths. When a garda detective is murdered, his body mutilated and dumped on gangland ground, she is called in. As a large-scale investigation takes shape to hunt down the killers, Terry's post-mortem uncovers uncomfortable evidence. She soon finds herself up against the powers that be. But, as new evidence emerges from her cold-case work that impacts closer to home, this may be the least of her worries.