Helen Mirren reprises her iconic role as the formidable Detective Superintendent Tennison one last time. As her exemplary career heads towards its inevitable conclusion. Jane is paying dearly for 35 years of repressed rage and loneliness.

When the body of missing schoolgirl Sallie Sturdy is discovered, the hunt for her killer begins. But as Tennison and her team work to identify their prime suspect, the emotional fallout from the brutal murder starts to take its toll.

As the investigation gets underway, Tennison is not only dealing very privately with the imminent death of her father but also an addiction to alcohol she is desperately trying to keep hidden. But as the pressure mounts on all sides to secure a conviction on the high profile case, the cracks begin to show. The boundaries between her professional and private life begin to blur as her personal demons become all consuming. As the investigation starts to slip beyond her control Jane forms an emotional bond with Sallie's closest friend, Penny Phillips, in whom she recognizes a kindred spirit.

While the crisis threatens to destroy the reputation of an exemplary career, Tennison struggles to stay afloat as the storm around her intensifies. Yet despite the occupational danger inherent in the relationship, Jane becomes unable to detach herself from the teenager, convinced Penny is her only lifeline.

With her superiors clamoring for her to take retirement early, her loyal team of DI Traynor, DS Simms and DC Cox close ranks. But this is Jane's personal journey, and her battle alone to fight. As she struggles to redeem herself professionally, she must first find redemption personally. But if the will to fight has gone, what hope is there of recovery?