It takes a pristine gift for mediocrity to ruin Mary O’Hara’s muscular children’s novel about a wild boy and his wild horse, but director Michael Mayer has brought off the massacre with aplomb. En route from the 1943 movie through the beloved 1956 television series into this sorry remake, the boy has become a Katie (Alison Lohman), and we can tell the kinship between girl and horse by the teased hair they both toss whenever adversity heaves into view. Mayer is primarily a theater guy, and his way with actors is stiff and awkward, though I can imagine country singer Tim McGraw (who plays Equally Stubborn Dad, a man who should be locked in a room with “Feelings” on the turntable) would pose a challenge to almost any director. The harsh, livid lighting gives the movie a distressed Ralph Lauren look, the score is Brokeback-plaintive, and the few scenes of genuine rodeo excitement are marred by the fact that Katie, by way of masculine disguise, has dressed herself up to look like Johnny Depp, the pirate version. Rain falls, sad things happen, and as we left the theater, I could have sworn I could hear horsy girls all over America, crying—with laughter.