Sequel to "Planetfall Twenty-Seven" the adventures of Cordan and Lareesa as they continue to guide the development of the new colony on the desolate planet with a carbon dioxide and nitrogen atmosphere. Life is complicated more by their low-tech construction in-orbit of solar power satellites, solar powered total recyclers, and a small space station. Life is further complicated by discovery of aliens arriving there from the next planet out, which had been seeded with marine species by the first starship centuries before. But these marine creatures had been given intelligence-enhancing biochemicals to enable their survival on the watery world, and it had worked very well.