Advertising materials tell us all we need to know about Step Up. She's a little bit Fame, and he's a little bit West Side Story. She's an ice queen, while he's a Vanilla Ice clone. We get it. Yet choreographer-turned-director Anne Fletcher does everything short of laying down railroad track and positioning her leads on opposite sides to hammer home the from-different-worlds hook that carries her fleet-footed tween fairy tale.Channing Tatum fills the baggy jeans of street-tough foster kid Tyler - all the truly edgy names must have been taken. Using a baseball cap and blank stare as method tools, the actor aims for the fiery rebellion of James Dean or early Richard Gere but achieves a flatness reserved for James Franco.This watered-down Eminem walks his own 8 Mile until the cops bust him for vandalizing property at the Maryland School of the Arts. Tasked with serving 200 hours of community service, Tyler mouths off to authority (Rachel Griffiths, longing for her Six Feet Under days), romances self-centered dancer Nora (Jenna Dewan), and discovers a career path that might one day lead him out of the ghetto.Fletcher's resume is littered with professional choreography jobs on films like Bring it On and Ice Princess. She pours her creative juice into this film's numerous dance routines, and it's during those moments that Step Up shows flashes of potential. Tatum and Dewan have limited ability as dramatic actors, but each can move to the beat with the best of them.Fletcher desperately needs someone in her cast to - pardon the pun - step up and elevate the film past the stacks of storytelling clichés cranked out by screenwriters Duane Adler and Melissa Rosenberg. Their script half tries, with unfinished results. Days after Tyler arrives on campus, Nora's dance partner conveniently drops out of her senior routine with a temporary injury. Nora's mother frowns on her unyielding dedication to dance, yet pays for her daughter to attend a private arts program. When Step Up reaches beyond the dance floor, exploring a gang grudge that leads to the death of someone close to Tyler, the movie fatally stumbles and never regains its footing.Step up? How 'bout you step off!?