Synopsis: In "Kati with an I," documentarian Robert Greene ("Owning the Weather") turns his camera on his teenage half-sister on the brink of her high school graduation. That backdrop offers nothing new, but Greene's patient, understated portrait renders a universal rite of passage in strangely alluring, poetic terms. A resident of the close-knit Christian community in Piedmont, Alabama, Kati Genthner doesn't have it easy. Greene captures a key moment of transition in her life during the three tense days prior to her graduation. A few months earlier, her parents moved back to their home in North Carolina after her father lost his job. Living with her friend Bridgette for her final two months of school, Genthner appears firmly entrenched in her surroundings even as she expresses a deep-seated desire to escape them. Her boyfriend, James, lacks Genthner's decisive energy to leave Piedmont, despite his pledge to stick with her when she goes off to college. Meanwhile, her parents urge her to drop the guy and come home. Forced to make big decisions without any reliable support system, Genthner looks perpetually troubled, and Greene captures her discomfort in close-up.