In 19th century Australia, teenaged brothers Tommy and Billy are returning from swimming when they meet with a shocking tragedy. Thirsting for vengeance against the man they believe has wronged them—their former Aboriginal stockman—the distraught brothers turn to the ruthless and cunning John Sullivan, the wealthiest landowner in the region and their father's former employer. Gathering a posse of British colonial police, they ride across the barren outback in pursuit. Their harsh and horrifying journey will have a devastating impact on Tommy, and will hold enduring consequences for a young country struggling to come into its own.