After the battle in which the men of the destroyer Walker and their Lemurian allies repelled the savage Grik, Lieutenant Commander Matthew Reddy is shocked by the arrival of a strange ship captained by one Commaner Jenks of the New Britain Imperial Navy. As tension between the Allies and the Imperials mount, Reddy will come to realize that his suspicions are not misplaced, and that a greater danger than the Grik is closer than he ever suspected.