Conan, once a powerful officer in Earth Federation's Star Command, has paid the price for saving his brother from the Rulers' just punishment. He is exiled, no longer a man but a one-armed eunuch--until famed cyborg-maker, Pak Song, fashions him new appendages.

Nebula, a woman with the mutant gene, has undergone sterilization. She seems a perfect mate for the resurrected Conan. Shunned on Earth, they seek their lifetime together on the utopian planet, Luna Ten.