This nicely plotted space yarn sends a young, pretty trainee in some future Peace Corps to an unpropitious planet where the human colonists have split up into a grim anti-mutant Puritan society and the bizarre evolutionary byways of the increasingly numerous mutants. The book's central genetic premise is ingenious and suspensefully introduced; Van Scyoc fleshes out the details of her fictitious world with satisfying inventiveness. The writing ranges from incisiveness to banality; the flaccidity of the heroine is a major structural flaw. On balance, however, an attractive achievement.