When Raf Kurbi's Terran spaceship burst into unexplored skies of the far planet Astra and was immediately made welcome by the natives of a once-mighty metropolis, Kurbi was unaware of three vital things:One was that Astra already harbored an Earth colony--descended from refugees from the world of the previous century.Two was that these men and women were facing the greatest danger of their existence from a new outburst of the inhuman fiends who had once tyrannized Astra.Three was that the natives who were buying Kurbi's science know-how were those very fiends--and their intentions were implacably deadly for all humans, whether Earth born or Star Born.