The Gene-Parasites

David terGorden and Narda are aboard a Collector, an organic spaceship, with Aura Damona Mar, an Oracle. The Collector is heading towards the exile of the Buds of the Tree, but Aura Damona Mar cannot fully control it. The Collector has absorbed Change Seeds, programmed gene modifiers, which have mutated due to radiation from Arioch into dangerous Gene-Parasites. These parasites are causing uncontrolled cell growth and tissue death within the Collector.

Aura Damona Mar reveals that the Gene-Parasites entered the Collector when David terGorden and Narda boarded it with the Sky-Stormer. She explains that the Gene-Parasites are attacking the Collector's organic material and that the Collector will die if the infection progresses too far. If the Collector dies in Space II, it will dissolve, killing everyone inside. Aura Damona Mar guides David terGorden and Narda through the Collector's interior toward the energy conversion center, hoping they can interrupt the energy intake and force the Collector back into normal space.

As they progress, they encounter Web-Nets, a form of the Gene-Parasites, which attack and paralyze Narda. David terGorden frees her, and they continue, facing increasing danger and the Collector's antibodies, which attack anything classified as foreign. Aura Damona Mar's influence weakens, and the Collector is drawn towards a Kaiser Force accumulation. They reach the energy center, but it's too late to fully deactivate it. The Collector is knocked off course by a World Tree and is now heading toward a sunless planet, the Solitary Wanderer.

David terGorden and Narda are ejected from the Collector as it enters the atmosphere of the Solitary Wanderer. They are separated. David terGorden is rescued by the Amrymm-Hoth, cloud dwellers led by Mramad. Narda encounters Fhlimag, a Pelzige, who guides her. Both are trying to reach the Stamm, a World Tree, to save the planet. David terGorden helps the Amrymm-Hoth fight off Air Leeches, and Mramad agrees to lead him toward the Stamm. Narda encounters Perina, a Procontrabitterin, who helps her reach the Stamm.

David terGorden reaches the Lenker, Mhyon, who is dying. Mhyon reveals that David terGorden is the Bearer of the Monochord and tasks him with awakening the Weltenbaum. David terGorden and Narda unite their powers and awaken the Weltenbaum. Aura Damona Mar, empowered by the Weltenbaum, regains control of the Collector and eliminates the Gene-Parasites. The Collector is saved, and the Solitary Wanderer is no longer threatened by the Kaiser Force accumulation. David terGorden and Narda fall asleep, dreaming of the Buds of the Tree and the Alte Wald. The Collector leaves orbit, seeking the Buds of the Tree.