Humanity is on the verge of extinction 15 years after the global apocalypse. Civilisation has vanished, food is scarce, and most people make a living by stealing and killing. One boy clings to life in the desolate British countryside, where avoiding others has been critical to his survival. But his self-imposed isolation comes to an end when he encounters another group of survivors and faces an enemy far more ferocious than any of them could have imagined.