Last year, Ann Hui’s “The Way We Are” was lauded for piercing through the media hype surrounding Tin Shui Wai and giving us an honest picture of ordinary people trying to get by in the so-called “City of Sadness.” It might come as a surprise, then, that her follow-up picture, “Night and Fog,” chooses to spotlight the more morbid aspects of life in the area. That said, the film is no less honest a piece of social realism than its earlier companion piece. Not only does it home in on the true malaise of the troubled new town, but also like its companion piece, it speaks volumes about where the rest of Hong Kong is today.

The film takes its cue from real-life horror stories in Tin Shui Wai, such as the 2007 case of a mother who threw her two children from a window before leaping to her own death—an episode many quarters of the press subsequently had a field day with. We learn about a similarly grim tragedy at the start, and the events leading up to it are then told through flashback. The drama surrounds Sum (Simon Yam), a violent brute and scrounger off the state, his mainland wife Ling (Zhang Jingchu), and their twin daughters.

Yam inhabits his character as sympathetically as possible, but ultimately we come to know Sum as nothing but an irretrievable thug. Mainland starlet Zhang meanwhile delivers a strong performance as his abused wife, hostage to far more dire circumstances than she knew at home across the border.

With her usual rigor, Hui successfully documents and dramatizes three issues of personal importance to her in Hong Kong today: the growing poverty gap, domestic violence, and the callous attitudes towards mainlanders that still linger in local culture. Some have questioned the film’s appropriation of its English title from Alain Resnais’ Auschwitz documentary. Whether this is deliberate (and why it might be) is unclear. You’re best off not puzzling over it through this tragic eye-opener of a drama, whose honesty delivers more of a shock than any of the sensationalism the papers could hope to cook up about Tin Shui Wai.

4 Stars by John Robertson.

Directed by Ann Hui. Starring Zhang Jingchu, Simon Yam, Jacqueline Law, Amy Chum. Category IIB, 122 minutes. Opened May 14.