The story is set in the future on the planet named Amoi which is controlled by a supercomputer named Jupiter. Among the mostly male human population, the blond-haired elite class is allowed to temporarily keep slaves as luxury pets. One elite member, Iason, encounters a lower class slum mongrel named Riki and decides to forcibly take him as a pet which is unusual and taboo in elite society. However, Iason keeps Riki longer than it is socially approved, and rumors abound about their possible relationship.