Idealistic Brother Rod and the Spirit Brethren sponsor an orphaned children's colony on the harsh and inhospitable alien planet Prokaryon. But the entire planet's ecosystem is too structured, too controlled, to be natural. So when Proteus Unlimited, a greedy interstellar corporation decides to strip-mine and then terraform the planet, the search for the intelligences behind the environment becomes a race against time. And what will happen to the orphans if the surface of the planet is boiled off?