A new restoration of this 1980 British cult classic makes plain that its themes of disaffection and racial discord in south London are still relevant nearly four decades later. Through the perspective of a DJ for a local reggae crew (Brinsley Forde), the city’s heated Jamaican subculture unfurls. It’s an intricate network, influenced by poverty and intraracial rivalry as much as anti-Black racism and police misconduct. The drama is notable for its cast of mostly young Black musicians and its refusal to shy away from troublesome territory. The movie also features a wellspring of talent behind the camera, from late director Franco Rosso to cinematographer Chris Menges (who went on to win an Oscar for The Killing Fields) to reggae producer Dennis Bovell, who supplies the film’s propulsive score. In English and Jamaican patois with subtitles.