Director Jia Zhangke’s epic tale of a changing China covers the years 1979 to 1990 and the mutation of a troupe of young performers. As the Fenyang Peasant Culture Group they performed propagandist praises of Mao, but come privatisation, they become the All Star Rock and Breakdance Electronic Band, purveyors of Taiwanese and Cantonese pop. And that’s just the beginning of the startling transformations.