As a child, Kotarou felt that he could not fit in with those around him. His parents take him to sit in on lectures at the Martel Group, an environmental protection organization, where he meets a young Akane who can only say a single word. At night, Kotarou uses his superpowers to hunt and kill various creatures he finds at school or in the forest, dubbing himself the "Earth-saving hunter". However, he is nearly killed by several dinosaur-like monsters one night, only for them to be destroyed by Esaka and his men...