Harry Cunningham is asked to review a case in a insurance dispute. The insurance company is refusing to pay out on an policy when the autopsy results show that the woman was intoxicated and likely was responsible for the fall that killed her. Her family insists that that is impossible as she was an abstainer. Nikki Alexander investigates when human remains are found buried in an field. The locals believe the body to be that of Clara Young, who had disappeared 18 months before. The remains are found on the site of a travelers or gypsy caravan site and the police are convinced that George Wood, one of the camp residents is responsible, but Nikki's evidence proves otherwise.

George Wood is released by the police but he is soon found dead in his caravan. Although made to look like a suicide, it is clearly a murder. The case gets even more complicated for Nikki and the authorities when she determines that there are the remains of two victims in the field, not just one. The evidence in the George Wood murder points to someone with connections to the police. Harry Cunningham believes that the dead woman in his insurance case was likely suffering from dementia and looks to prove the cause

Sam Ryan recruits the Lyell team to investigate the assassination of the health secretary, but Nikki is unsure whether Sam knows more than she's letting on.

DNA evidence linked to the health secretary's assassination forces Nikki to face her past in the present. As her investigation progresses, Nikki realises that its consequences will affect her, and her profession, forever.

The death of an investigative journalist throws the spotlight onto Sam Ryan. Nikki begins to realise that the implications of her discoveries will challenge the principles of forensic science.

Events lead Nikki to conclude that getting the truth will put the Lyell team and everything they love in danger.