This is the story of tribes who lived in ancient times without even knowing the use of metal, and who improved their civilization through contact with some aliens. Those who lived in harmony with nature learn from the aliens that they can fulfill their needs artificially. That small development of civilization turns those who were originally cowards into warriors. This story narrates the adventure of the young lovers who lead the tribe, who stand up to and destroy a group of savages who are the enemies of their tribe.