Staying on in Iowa at her great-grandparents' farm while her parents find a home in NYC, where Dad has a lucrative new job, Trapp clings to the turf whose impending loss is entwined, for her, with ""Grandma"" and ""Grandpa's"" mortality -- an idea given poignancy by the death, a year ago, of ""Nana Q,"" their daughter and Trapp's grandmother. Trapp, naturally solitary, thoughtful, and affectionate, pitches in with chores and observes her elders' happy 60-year relationship. Mystified at finding ancient carved initials -- Grandpa's ""RH"" with ""GS,"" not Grandma's -- she pieces together subtle clues (word choices, old photos) and arrives at a startling truth: Nana Q was adopted. This fact, which 50 years of rural reticence has rendered a secret, recasts Trapp's inner world, her concept of family, and her view of her birthplace (like the woman who bore Nana Q, she'll carry it in her heart, but it won't hold her). She also senses that her over-orderly mindset could be tempered by openness to chance. At this turning point in their history, Fakih's characters are leading fully examined (and discussed) lives; but though her narrative is leisurely, it holds interest with its unexpected flashes of humor and its engaging evocation of the Heartland and some of its sons and daughters, as well as the tantalizing mystery. A beautifully constructed book, rich in offbeat descriptions and exchanges that leave room for just the kind of serendipitous insights that ""GS"" -- who does turn up -- extols.