Geologist Emily Hansen, working as a mudlogger in the Tensleep Sandstone oilfield near tiny Meeteetse, Wyo., is sorely troubled by the seemingly accidental death of head geologist Bill Kretzmer and the subsequent killing of his protÇgÇ Willie Sewell, who had suspicions of his own. Inexplicable things are happening at the drilling operations, too, all of it overseen by vulgarly nasty company engineer Ed Meyer and his quiet sidekick Merle Johnson. Em investigates some disquieting minor occurrences: horses' hoofprints in strange places; a missing drill bit used as a doorstop for her primitive, on-site trailer; tank trucks moving without lights in the wee hours; papers vanished from Kretzmer's Denver office. It all comes together in a way that nearly kills a doggedly persistent heroine. Oil-drilling operations and the rough-mouthed, rough-living characters who do the work get robust treatment here, but with the same sweet edge that enriches Em's spiky character and gives subtle nuancing to geologist Andrews's unhackneyed, accomplished first novel.