Snappy stylist Maristed (Out After Dark, 1993) shows herself to be a scathing sociologist--if a less than thrilling mystery writer--in this occasionally romantic fictional exposÇ of the world of show jumping. It's a world where hard-as-nails trainers put their teenage riders through a hellish summer on the way to national competition. Unsavory practices in this moneyed culture include doping steeds so they'll perform better, and bumping off highly insured mounts for the money. Lex Healey is a 40ish drifter who's fallen in with this set largely, it seems, because of his practical wardrobe: T-shirts and jeans (good around the paddock). A security man who bumbles more than he protects, Lex has a fling going with the trainer everyone loves to hate, Erica Hablicht, an outsider whose riders have a habit of triumphing against established favorites. It's unclear whether Erica shares Lex's dizzy lovesickness, but she certainly doesn't let her reservations show when they're boffing, which is often. Minor characters--Hispanic grooms, slimy insurance investigators, loudmouth WASP parents, and unscrupulous trainers- -nip around the edges of the plot, but the one Maristed focuses on- -to the tale's detriment--is Ruth Pryor, a former rider crippled in an auto accident. Like a paralyzed Nancy Drew, Ruth motors around the shows in her golf cart, determined both to solve the mystery of several suspicious horse deaths and to learn the identity of the man who crippled her. She emerges as a tragic figure, but her story can't compete with Lex and Erica's more straightforward struggle. Lex is playing detective, too, but his talentless fumblings are clouded by Maristed's tendency to spend more time displaying her vast knowledge of what show jumping is about than in sticking to the mystery. A well-told and sinuously written story, full of flashes of brilliance. But, unfortunately, it deals with such a small sporting universe that it runs the risk of eluding the notice it deserves.