I love book titles with “quest” in it. The quest is still for immortality and our friends find themselves in the distant past of the Vegan planet. There they need to fight off the barbarians and they need to convince the Arkonide explorer Kerlon to try his luck on Earth, for some reason.
The highlight of the book is when Darlton says that Anne Sloane, one of the Mutants, proved that women too are capable of logical thinking. Because she proposed a plan, that was not worse than that of a man. Perry Rhodan writers were real feminists.