In a near-future Australia, the death penalty is reinstated. The catch: the family of the victim must carry out the sentence. One family member gets twenty-four hours in a room with the condemned. No cameras. No microphones. They can dole out whatever punishment they decide. The only rule: at the end of the twenty-four hours, the criminal must be dead.

When ten-year-old Lucy is murdered, her family is doubled over with grief. While her killer waits them to decide on his fate, psychologist Octavia Tate is assigned to guide the family, living remotely on their ethical cattle farm, through their decision, but she finds herself amidst a family at war with different views on what constitutes justice. Lucy's mother, Stella - a survivor of domestic abuse - harbours a desire to carry out the sentence, and a burning fantasy of revenge. Her wife, Matisse, the creative earth mother and calming presence, can not support her, because she harbours a secret: she has taken a life before and is not willing to do so again. And Sebastian - a vet with the golden-retriever temperament - refuses to participate, but only for fear of darker inside urges. Meanwhile, bookish teenager Hannah, too young to be legally allowed to participate, has her own plans.

As the execution date nears, and Stella is adamant that she has to carry out the punishment, Octavia realises the truth: if Stella steps into the room, she will not survive it whole.