Season 1

When an Irish couple goes missing in New Zealand, Dublin detective Theo Richter heads to that country in search of a possible gang connection. There he teams up with a young Māori detective sergeant named Diana Huia to try to find out what happened.

After learning more about the missing couple, Sinead and Ronan, the detectives suspect Irish gangster Derry Fallon. Sinead's parents join the search, but news of a violent incident causes Diana to look a little closer to home.

The team is forced to let Fallon go after it becomes clear he's innocent. When Irish journalist Aileen disappears and the case begins to fall apart, Theo looks to his Dublin colleagues for help locating her.

With two bodies in the morgue, Theo and Diana make a discovery that connects Sinead and Ronan to a historical case known as the Mountain Murders. The team must question if they have a copycat-or if the serial killer has returned.

Diana and Theo have a convincing suspect in their sights, but a shocking move and new evidence make the detectives feel like they have failed. Meanwhile, Aileen's latest encounter leaves her with more questions than answers.

Although scheduled to fly home the following morning, Aileen takes a risk to break the story after receiving an anonymous tip. Theo and Diana are caught up in a deadly confrontation, and Theo is forced to face his demons.