In a breathtaking but remote mountain town in South Island, New Zealand, a twelve year-old girl named Tui is discovered to be pregnant. Local police enlist help from Detective Robin Griffin, a child protection specialist who has recently returned to the area to care for her mother.

As Tui's disappearance remains unsolved, fear for her survival increases, while her father solicits help, Robin has a run-in with the girl's half-brother and a perverted local.

Robin makes a breakthrough in her investigation, but Al warns that her own dark past is colouring her judgement.

A violent indiscretion sees Robin thrown off the case but she cannot let go. Her passionate affair with Johnno, Tui's half-brother, intensifies and complicates.

Robin is back on the case, whilst Matt gathers troops to hunt his daughter down. Tui's friends trek deep into the mountains to celebrate her birthday, with tragic consequences.

Tui is about to give birth. Matt reveals a secret that almost destroys Robin. The investigation reaches its shocking conclusion.