The documentary Audience Award winner at this year's Sundance festival, Buck follows itinerant horse trainer Buck Brannaman as he applies his uniquely humane and frankly astounding methods in four-day clinics around the country. If that sounds as exciting as watching hay turn yellow, director Cindy Meehl finds the real story in Brannaman's fractured past as a child celebrity trick-roper who, along with his older brother Smokie, was systematically abused by their alcoholic father. Despite these odds, Brannaman grew into a preternaturally gentle adult who channels hard-earned patience and compassion into his work. You can hardly blame him if he plays to this narrative hook with a showbiz veteran's skill, and Meehl generally resists identifying too closely with her subject. She gets candid comments from Brannaman's associates and childhood friends. Lest Buck get too clubby and touchy-feely for its own good, Meehl closes the film with a sobering last-act scene in which the trainer encounters a raging, haphazardly reared colt even he can't reach. It's a subtle and harshly evocative reminder of how differently his life could have turned out.