Who is stalking Mathias? Is it related to the murder of Aron Bowen? All will be revealed in the series' climax.

A burnt body on the dunes embroils the team in a long-standing family feud with a connection to the murder of a young mother 13 years earlier. Mathias is convinced the young woman's murder holds the answers, but Prosser isn't keen on Mathias delving into the past.

In a world full of dark secrets will Mathias and the team unravel them before another person is killed?

The discovery of a body in a lake leads to an investigation about a local primary school teacher.

Why did Nora and Daniel live such a secluded life? What has Mathias discovered in the garden?

The murder of a local dignitary and barrister leads to the uncovering of a tragic story of love and loss fuelled by distrust and suspicion in the depths of the Hinterland.

The team have a suspect to question, but Mathias believes he is an unlikely killer. In his current state of mind, Mathias is fascinated by the lifestyle choices of ex-soldier John Bell. He also knows that he cannot avoid Meg for much longer.

Mathias is under pressure. Meg Mathias, his wife, has turned up in Aberystwyth, and he's under investigation by the IPCC following the death of Mari Davies. When a bus driver's body is found shot on an isolated mountainside, the investigation provides a welcome escape for DCI Mathias.

The climax of the first series saw DCI Tom Mathias pushed to the edge; with a local woman's death on his conscience and blood on his hands, the series came to a dramatic end with Mathias' future hanging in the balance.

Mathias' struggle to differentiate between his professional duties and personal feelings should have left his career in tatters, but Chief Superintendent Prosser has other ideas, and the one-off special episode begins with Mathias' difficult return.

DI Mared Rhys, who has led the team in Mathias' absence, is forced to step aside as her old boss investigates an arson attack on an isolated farmhouse. An attack that has left a mother and child fighting for their lives.

As the investigation unfolds Mathias is drawn into a community of failing farms, festering resentments and long standing feuds. Suspicion falls on several in the community, including the victim's husband - a local timber merchant who was unscathed by the attack - and a young man displaced by the closure of his farm.

With lives hanging in the balance, Mathias is forced to act, but what is it about this case of a mother and child that draws him in, pulling him back from the brink? Could it be a connection with his dark and troubled past?