The world is populated by two opposing races, "humans" and "beastmen." The humans, who outnumber the beastmen, avoid the beastmen, who are humanoid but have the characteristics of beasts, and have organized an extermination squad to persecute them. One day, Megumi is suddenly chased by the exterminators, but is rescued by Ares, a one-eared beastman, and his friend Sou. During her escape, Megumi discovers that she is neither human nor beast, and is confused by the sudden disintegration of her daily life.