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.