This first novel about the hothouse world of wealthy adolescent girls begins with the 15th reunion of a knot of prep school friends, and the first pages smack of Rona Jaffe--but read on. . . . Once the author brings her group back to Miss Pratt's School as new girls in the early Sixties, things grow far more resonant. The school, serving mainly the Eastern WASP insular rich, is administered with iron caprice by headmistress Mrs. Umbrage--who supplies a traditional curriculum, maudlin rituals, spartan fare, and arbitrary punishments (an object lesson in how to ""bow to the inevitable""). Five girls, strengthened and comforted by their friendship, survive both the school years and vacation triumphs and traumas: Lisa, good-natured and quite beautiful, the pride of parvenu parents; intellectual Anne; gentle Muffin, who loves horses and hates her nickname; Jenny, child of a well-known widowered actor whose male lover, kind and supportive, Jenny adores; and likable, reckless Sally, whose two wild brothers indulge in hilarious capers that are edged in cruelty--product of a splintered, loveless home. At the school or abroad or at society's tribal rites (""coming out"" productions or the elevated violence of the hunt), the girls run a high adolescent fever, pursuing love and sex with the heat of maenads, risking both comic shallows and deep hurts. Jenny and a young Latin teacher find the right love but at the wrong time; Muffin's soulmate turns to a swine; Sally, tragedy-bound, flounders; Lisa, passion-tossed, marries on the sly; and Anne has a dream-like morning of love with Muffin's father. With school ceremonies, hellraising, genuinely funny quips and pranks, Gutcheon has an impeccable fix on time, place, and native customs--and, within all the hoohah, the pathos of a vanished youth. Blatantly derivative of F. Scott Fitzgerald, but the dash and color and detail are all Gutcheon's own--a promising debut.