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.

The Claymore warrior Teresa has broken the cardinal rule that forbids her kind from killing humans. In time, a group of Claymores comes to kill her, and yet Teresa defeats them all with her superior skill and experience. But rather than slay the powerful ringleader, Teresa decides to spare her instead--an act of human weakness that will have devastating consequences for them all.