A woman's suicide is thought to be related to another death. The independent investigator makes an admission to Mared which gives her a lead regarding the case she is investigating with Tom. More than one person stands in their way.
An estranged husband kidnaps his son. Mathias and Rhys make a dark discovery at his parents home. Mathias risks his own life by searching alone. A former Superintendent puts pressure on the independent investigator to close another case.
A minister has been killed. Mathias and Rhys investigate his life and violent death. DS Owens leads an investigation into the attack on Mathias and his home as he struggles to keep his emotions under control. Prosser faces an old rival.
A curator's body is found in a shallow grave. The team investigate her death. Mathias comes under suspicion when another dead body is discovered. An independent officer is appointed to investigate the death and invites DS Owens to help him.
The body of a young woman is found abandoned but carefully placed in the marshes. This case, in the series finale, pushes DCI Mathias to the edge, both personally and professionally.
A solicitor is found murdered. There is hostility in the community towards Daniel Protheroe. Mathias needs to find him before the vigilantes. Mathias knows that the relationship between the daughter of the gang's leader and Daniel is key.
The team investigate the personal life of Greta Pritchard after discovering a body in her car. Who is the mysterious girl hiding from Mathias? This is a world full of secrets. Will Mathias and the team unravel them in time?
On his first day on a new job DCI Tom Mathias investigates a blood soaked bathroom and the disappearance of 64 year old Helen Jenkins. The inquiry focuses on an old Children's home above the ravine spanned by the Devil's Bridge.