Ben Mullinkosson is a film-maker and skateboarder from Chicago who brings an effortless, freewheeling intimacy to this immersive and sensual study of the underground club scene in Chengdu in central China. The title is enigmatic, but it seems to refer to the imminent closure of a club called Funky Town where his subjects have been hanging out; the darkness is the club’s darkness, which is enfolding and welcoming and reassuring, a neon-detailed night in which nothing matters but youth, beauty and the pleasure of the moment.

Mullinkosson is utterly at home and embedded with his group of friends – clubbers, performers, musicians – with whom he hangs out while they (utterly unselfconsciously) get very drunk; and in fact the spectacle of people throwing up in the street becomes a bit of a motif. He isolates a very strange setpiece in which a young woman rocks back and forth in the foreground as a prelude to a gruesome vomiting episode while two people in the background chatter away, entirely unconcerned.

Mullinkosson also gets up close and personal while people kiss, or fight. He is alongside a couple who have gone to a high rooftop to see the sunrise over the breathtaking sci-fi vastness of the city, and sees a woman who is depressed clearly flirt with the idea of taking her own life as she stumbles morosely to the edge to see the view better. Another character confesses candidly to having been molested on a certain spot as a seven-year-old. A drag artist has a kind of existential crisis (“I don’t even like seeing myself as a girl”).

The director brings his movie to a kind of vibey, coming-of-age climax to David Bowie’s Life on Mars and there is something very sad in seeing all the people involved bidding a kind of complicated, conditional farewell to hedonism.

• The Last Year of Darkness is on Mubi from 15 March.