First science-fiction outing for the author of Snow-Eyes, etc. (not reviewed). In the middle of the next century, after a disease- induced breakdown of society, the village of Monkar clings precariously to existence on America's northwestern coast. Nearby stand some ruinsof a lighthouse?that once contained machinery, long since scavenged by the villagers, and papers headed ``UBAS'' bearing lines of code that none can interpret. The women of Monkaramong them sensitive Emily, earth mother Maria, and doctor Aliceare unable to bear normal children; those who survive infancy are decidedly but indefinably odd. Now, four villagers have decided to trek south, braving such dangers as ``trolls'' (deadly machines) and ``deecees,'' government operatives intent on stamping out the ``ubes'' plague that killed all male children. Only when two members of the expedition return with horrifying tales to tell do the villagers make an effort to put the pieces of the puzzle together: Their children are hermaphroditic, amphibious seals, and communicate in an ultra-high-pitched, complex, and beautiful language of their own. The backdrop's an infuriating mixture of the enigmatic and the obvious, and too much happensnot always convincinglyin the last few pages; still, a smoothly handled, intriguing, sometimes unsettling drama.