On planet Geta, a long-abandoned human colony struggles to survive amid a hostile, genetically incompatible local biota, and famine is endemic. So the Getans have evolved various social systems based on cannibalism, whereby those low in ""kalothi"" (Darwinian survival ability) sacrifice themselves for the common good: bodies are food; indiscriminate slaughter (i.e. war) is unthinkable; the ruling priestly clans worship an ancestral spaceship and practice grisly rituals; the dominant Kaiel are managers; their deadly rivals the Mnankrei are sea-masters; the clans direct their own evolution via eugenic cloning and breeding programs but are largely ignorant of physical science. And within this deep, subtle, always logical construction, move three ambiitious Kaiel brothers: impetuous Joesai, calculating Hoemei, and peacemaker Gaet, who hope to complete their group marriage with the inception of physicist Kathein. But Prime Predictor Aesoe, coveting Kathein, orders them instead to approach Oelita, a heretical young woman who exerts control over a neighboring seacoast. So the frustrated Joesai initiates a courtship rite, a series of seven murderous trials which Oelita must endure to prove her high kalothi. . . while the hateful Mnankrei are breeding pathogens combining human genes with local lifeforms in order to strike at the Kaiel. Reminiscent of Frank Herbert (short, intense chapters, didactic asides), this first novel by a veteran sf storyteller is a feat of nonchalant, assured complexity: rich, teeming, somewhat weak only in characterization--and decidedly not for the squeamish.