Shannon and Rohan Scott have retreated to their family's cabin in the Australian bush to escape a virus-ravaged world. After months of isolation, Shannon imagines there's nothing he doesn't know about his older brother, or himself – until a stranger slips under their late-night watch and past their loaded guns.
Reluctantly the brothers take the young woman into their fold, and the dynamic within the cabin shifts. Possessiveness takes hold, loyalties are split, and trust is shattered. Before long, all three find themselves locked into a very different battle for survival.