In a world where monsters called Yoma prey on humans and live among them in disguise, humanity's only hope is a new breed of warrior known as Claymores. Half human, half monster, these silver-eyed slayers possess supernatural strength but are condemned to fight their savage impulses or lose their humanity completely.

Teresa, a powerful Claymore, saves a young girl from her bandit captors and leaves the child in the care of some villagers. But triumph quickly gives way to despair when the situation takes a tragic turn, and Teresa is forced to kill a human--an act that will condemn her to death at the hands of her own kind.