L.I.E., stupidly rated NC-17 by the reliably dense Motion Picture Association of America, concerns teenage boys and an older man who preys on them sexually. It’s a disturbing fact of life, and when handled responsibly, as it is by director/co-writer Michael Cuesta in L.I.E. — meaning without nudity or pandering — the topic can provoke a vital discussion between older teens and parents. The NC-17 rating, barring those under seventeen from attending the film, cuts off the discussion. Such hypocrisy is invariably at the expense of indie films, while studio product such as American Beauty, in which Kevin Spacey enjoys graphic fantasies of the underage Mena Suvari, slides by with an R rating. The system stinks; Cuesta’s movie does not. It’s a powerful and provocative achievement from a first-time filmmaker of enormous promise. L.I.E. stands for the Long Island Expressway, which runs past the New York suburb where fifteen-year-old Howie (newcomer Paul Franklin Dano is remarkable) lives with his widowed, workaholic father, Marty (Bruce Altman). Howie’s pal Gary (the terrific Billy Kay), for whom Howie is feeling erotic stirrings, gets him involved with a teen gang that robs houses. One day they break into a house owned by Big John (Brian Cox), a local kingpin who buys sex from boys. When Howie’s dad is arrested for using unsafe building materials and Howie is virtually abandoned, Big John steps in as paternal figure and predator. The ambiguity of the role is sure to stir controversy, but Cox — who delivers one of the year’s best performances — catches the troubling complexity of a man who can’t be written off as a stereotype. Real villains don’t wear signs to warn vulnerable kids. How like the ratings board to censor a film from which both teens and parents might actually learn something.