Barton, hero of The Proud Enemy, is the only escapee from an alien planet upon which all members of captured races are surgically altered to become like the "one true race". Leading a new fleet of Earth ships, he ventures into deepest space to join the other races under attack. Thus is the first blow dealt to the alien slavers.
But Barton receives advice from yet another mysterious race by means of a strange, oracular pronouncement: go to the holy planet of the alien slavers, find their secret and the galaxy-wide plague of raiding will stop.