Twelve years ago, Stephan wrote a likable, atmospheric satire (A Dam for Nothing), and the strengths of her mystery debut come from atmosphere and character rather than from plotting ingenuity or suspense. Three families are sharing an uneasily communal, back-to-nature existence in a broken-down house on a near-barren farm in Massachusetts: a pair of natural-everything nuts; a lazy, alcoholic writer and his dancer wife; and the middle-aged Atkinses, George (gung-ho) and Emily (ironic and dubious). When vandalism and obscene letters start plaguing the mÃ‰nage, can murder be far behind? On hand to investigate is Sgt. Dave Putnam, country-smart and roughly sweet, and, though his solution is less than neat or convincing, he and his suspects are welcome, three-dimensional figures against the vivid backgrounds of a gossipy small town and the bleak countryside.