One-off special episode where Mathias is called back to duty to investigate an arson attack on an isolated farmhouse.

DCI Mathias investigates the murder of a local bus driver while being investigated himself for his emotional fitness to perform his duties.

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?

DCI Mathias is tasked with solving the case of murdered Aron Bowen.