Third entry in Sargent’s interstellar colonization saga that began in 1983 and continued with Farseed (2007).
After Ship founded a colony on planet Home, it flew off to continue its mission. The colony, meanwhile, sundered into disparate and untrusting groups. One remained in the domes built by the founders, using the advanced technology left them by Ship, and claims to be the only true humans. Others preferred a natural environment and wandered down a huge river toward the sea, creating a simple, peaceful agrarian culture of scattered villages. Both fear Ship as a godlike entity that will return to judge them. Villager Nuy, the heroine of the previous book, is now the oldest human on Home, and when she discerns an enigmatic new light in the sky she knows that Ship is returning. Nuy's descendant, Bian, vows to travel upriver to speak with the dome dwellers, who have a radio and therefore must already be speaking with Ship. All the dome faction’s adults are dead, however, the oldest being teenager Safrah, while the younger children have turned agoraphobic and feral; worse, their technology is failing—and somebody has sabotaged the radio. Mutual antipathy, alas, is no substitute for a plot, and the youthful, incurious cast’s inability to think or plan quickly grows tiresome.
Put this one back on the YA shelf where it will find its natural audience.