Only children can colonize the planet Prokaryon, genetically modified for a world whose chemistry kills unaltered adults. A colony of orphans struggle to survive, and find the planet hides strange secrets. ***** The Prokaryan landscape is ordered, as if by unseen gardeners, "hidden masters" no human has ever found. The weather behaves as though designed to meet the planet's needs. When fire threatens a forest, a rainstorm appears, only to dissipate when the fire is put out. ***** When a ruthless corporation threatens to terraform Prokaryon, to recreate it for "normal" humans, there is a sudden urgency to find the intelligent life form directing the planet. For only then can the colonists save their world-and reveal unexpected possibilities for the human future.