On the planet Amoi, a person's status is primarily determined by the color of their hair. This society is governed by the AI supercomputer known as Jupiter and its ruling board of perfect blondes, called Blondies, who reside in the capital city of Tanagura. However, darker-haired humans live their lives in the golden "pleasure city" of Midas and its surrounding slum, Ceres. They are referred to as "mongrels," and most are unable to rise above the slums. Three years ago, a boy named Riki vanished from the slums of Ceres. Once the respected leader of the gang Bison, a sudden encounter with an elite Blonde, Iason Mink, forced Riki to abandon everything he had built. The boy was taken from his home and compelled to become Iason's pet. Riki has spent the past three years enduring repeated blows to his pride, with his time in Tanagura amounting to nothing but torture. Now that Riki has returned, Bison once again rallies behind him. The danger he faces, however, is far greater than ever before—there is always someone ready to betray him.