In the future, on a distant star lives a new society. Ruled by a computer system, named Jupiter, men are divided into classes based on their hair color. The Blondies, genetically altered by Jupiter, are the highest class and occupy the capital city of Tanagura. Those with black hair, Mongrels, are forced to live in the slums, Ceres. Iason, the leader of the Blondies, encounters Riki, a mongrel, in the streets of Ceres one night and sets out to own him.