Musicologist Ngawang Choepel, a Tibetan exile in Dharamsala, India, returned to his homeland in 1995 to archive vanishing native folk songs but fell afoul of the occupying Chinese government; it sentenced him to an 18-year prison term for “endangering its national security” before an international protest forced his release in 2002. This documentary combines what the director shot before his incarceration with additional footage recorded by colleagues in 2004, and it’s a harrowing look at the coerced nationalization of a people, whose culture the Chinese erode through threats both physical (prison, torture, execution) and psychological (blaring Chinese music, the replacement of authentic Tibetan singers with party propagandists). What the film lacks is a broader history of Tibetan music. In English and subtitled Tibetan and Mandarin.