"The Folk" are a shipload of refugees recently escaped from a race of cruel masters who employed them as combat troops and kept them in a state of technological ignorance. With few resources beyond a melange of battered neo-Irish myths and a stock of advanced but irreplaceable weapons, they are trying to colonize an Earthlike new home. Ciaran, daughter of the colony's leader, heads those trying to overcome the Folk's superstitious dread of anything alien. The chief targets are the highest form of native life (the "Seademons," an octopus-like race) and Maeve, a wild human foundling popularly reputed to be a witch and certainly on terms of strange intimacy with the Seademons. Maeve's beauty leads two of Ciaran's brothers to their deaths; the entire Folk is drawn into the ensuing tragic campaign against the Seademons. Yep, author of well-received juveniles, has not previously tackled an adult novel; this one falls uncomfortably somewhere on this side of the young adult category. The emotional range is truncated, and much of the dialogue is pallid and soon-palling badinage. But the situation is outlined with imaginative verve, and the story is put together with confidence and smoothness. Hard to categorize, but nice.