Irish Detective Theo Richter travels to a small town in New Zealand and teams up with Māori Detective Diana Huia to find a missing Irish couple.

As Diana struggles with being on home ground. Richter fights his own demons as they both work hard to find Sinead and Ronan.

Irish gangster Derry Fallon becomes a prime suspect in the couple’s disappearance but when he remains elusive and Irish journalist Aileen Ryan disappears, the case begins to fall apart.

With two bodies in the morgue, Richter and Diana make a discovery which connects Sinead and Ronan to a historical case called the Mountain Murderer.

A murderer revealed, the race is on to find Sinead but when hope is lost, the case is closed until an unexpected return marks a new beginning.

The extent of danger the town faces unfolds. Aileen risks everything and when Diana and Richter finally face the murderer he has to conquer his demons if he wants to survive.

When Irish journalist Aileen Ryan goes missing, Irish Detective Theo Richter and Kiwi Detective Diana Huia are compelled to remain in Mt Affinity, New Zealand to lead the search.

As Diana and Richter struggle to make sense of what could have happened to Aileen, and fearing the worst, they discover another Irish person is missing.

The truth about how Aileen went missing is revealed. The detectives find the two missing Irish, but when one still ends up in the morgue, they now have a homicide on their hands.

Evidence suggests the Mountain Murderer is back and responsible for the latest killing, leaving a trail of breadcrumbs for Diana and Richter, who close in on a very unlikely suspect.

A convicted criminal linked to the case escapes from prison as Diana and Richter track down their latest suspect.

With Mount Affinity locked down with lead suspect Frank Pastor on the loose, Diana and Richter must solve the case before the Mountain Murderer gets to their next victim.