The capricious ways of nature frame this eighth novel by the popular Bohjalian (Midwives; Trans-Sister Radio). Several years after the devastating loss of their nine-year-old twin daughters in a flood, Vermont residents Laura and Terry Sheldon decide to adopt a child. When a state agency grants them a taciturn 10-year-old African-American boy on a foster-parent trial basis, they acquiesce, albeit with some reluctance. The trial is no less unsettling for the child, Alfred, who has already endured separations and is aware of his solitary status in the small, white town. What will save the boy, and lend poignancy to the novel, is a growing friendship with an elderly neighbor, Paul, a retired teacher, who accepts him without preconditions. He gives the boy a book about a post–Civil War western black cavalry unit, the Buffalo Soldiers, and a cap with a picture of their buffalo symbol and then invites the boy to learn to ride his horse. Alfred, moved by the book, responds to Paul and begins to break out of his isolation. Bohjalian writes honestly and often movingly, but his characters do not escape stereotyping. Terry, a uniformed state trooper, is all tough policeman when he catches Alfred arranging a hidden stash of food. He angrily accuses him of thievery, insensitive to Alfred's fear that he may be rejected and need to escape. Laura, an unhappy, colorless character, is only lent dignity by her growing love for the boy and a willingness to understand him. In an echo of the book's opening scene, another natural disaster brings the novel to a handy but credibility-straining conclusion. Bohjalian's facile handling of both plot and narrative makes for fast reading, but fans may conclude that the result feels rushed and cursory. 13-city author tour. (Mar.)