Grukel Athosien, a Concept sent by It, materializes on the Moon. His mission is to see if Goshmo Castle can be the new home of the humanity that It has absorbed shortly before the Earth disappeared in the Pharynx.

When Athosien tells Rhodan and Danton he needs to use the Iron Duke for his mission, the two men oppose him, afraid that his actions will draw the attention of the Hulkoos. Athosien manages to escape on board the Iron Duke and the Hulkoos suddenly realize that the Terran base on the Moon has been reactivated.