Jennifer Kent’s debut feature “The Babadook” was one of the most imaginative and chilling horror films of recent years, featuring an exceptionally unusual boogeyman, and her second is no less unsettling, but in quite a different way. There are monsters in “The Nightingale,” but they’re all of the human variety, and perhaps more frightening for that very reason.

Though the film runs for over two hours, the scenario is rather a simple one, involving a difficult journey motivated by a desire for revenge. In early nineteenth century Tasmania, or Van Diemen’s Land as it was then known, two Irish exiles, Clare (Aisling Franciosi) and Aidan (Michael Sheasby) have married and had a child, but while he has completed his term as a convict and received official confirmation of his freedom, she remains in thrall to British Lieutenant Hawkins (Sam Claflin), despite having completed her seven-year sentence, since he refuses to provide documentation proving her release.

Hawkins is infatuated with Clare, compelling her to sing for his band of ruffian soldiers, including Sergeant Ruse (Damon Herriman) and callow Ensign Jago (Harry Greenwood), and forcing her, unbeknownst to Aidan, to have sex with him. In a confrontation that becomes heated, Aidan demands that the officer certify his wife’s release papers, and when Hawkins decides to leave for the northern town of Launceston to seek promotion to a captaincy for which his on-site superior declines to recommend him, he—along with Ruse and Jago—stop at the couple’s cabin to exact retribution for the insult. The sequence is but the first of several that will convince some viewers to divert their eyes from the screen.

Clare determines to pursue the three men as they traipse through the wilderness, and manages to hire an aboriginal guide named Billy (Baykali Ganambarr) to lead her. She and Billy are initially hostile to each other—she sees him as dangerous (the action is set in the midst of the so-called “Black War” of the late 1820s and early 1830s, and there are sporadic glimpses of the violence brought on by the ethnic strife—farms set ablaze, corpses hanging on trees), while he initially identifies her with the Brits who have slaughtered his family and stolen the land. Eventually, however, as they tell one another of their lives, they see each other as having a common enemy in the English, who after all were seen as oppressors by the Irish too, and they grow more understanding—and more protective—of one another.

The narrative juxtaposes their journey with that of Hawkins, his men, and the minions they have brought along, including a boy named Eddie (Charlie Shotwell); they too have an aboriginal guide, an old man named Charlie (Charlie Jampijinpa Brown), who ultimately reveals his own agenda. The soldiers’ lust and casual cruelty explode sporadically as they go, particularly after Ruse encounters a native woman (Magnolia Maymuru) and her child in the forest. But Hawkins mistreats his own men as well as the aboriginals; handsome but hot-tempered, he’s quick to take up his pistol at the slightest provocation, even against Eddie, whom he tries to train as a personal acolyte.

Clare’s desire for revenge, and Billy’s equally great sense of the injustice he and his people have suffered, do ultimately find release, though in unexpected ways. The film seems poised to end before the two-hour mark, but an abrupt change in one character leads to a final act at Launceton that brings not one scene of retribution but two very different ones. It’s here, especially, that “The Nightingale” moves beyond being a grisly tale of personal revenge to emerge as a wrenching microcosm of the results of cultural imperialism.

The power of the film is attributable first and foremost to Kent’s script and hyper-realistic direction (accentuated by Radek Ladczuk’s grim, gritty visuals, shot in forbidding locales, as well as in hand-held style and the constricting academy-box format, and by Alex Holmes’ grimy production design and Margot Wilson’s costumes, among which only Hawkins’ uniforms—and those of the other soldiers in Launceston—sport bright colors).

But its impact is equally dependent on the performances, especially Franciosi’s ferocious turn, which captures both Clare’s tremulous vulnerability and her apparently adamantine resolve—as well as her undying sense of nationality. Ganambarr, though not so overtly intense, is equally effective, embodying more resignedly the intense pain of a whole people being oppressed and nearly exterminated. Claflin, meanwhile, conveys perfectly how utter malevolence can exist under a handsome surface and a veneer of cultivation, while Herriman shows the stupid brutishness of one of his underlings and Greenwood the cowardly acquiescence of the other. There is outstanding support, from Sheasby, Brown, Shotwell and Maymuru in particular.

“The Nightingale” might be compared to “Midsommar,” the recent sophomore effort by Ari Aster, whose “Hereditary” was also an auspicious genre debut. Visually the two films couldn’t be more different, Aster presenting his horrors in luminously bright images while Kent’s film is relentlessly dark and gloomy.

But both films are notable for extremely high levels of violence and sexuality, which will prove highly disturbing to many viewers—Kent’s perhaps more so, since it is presented in a less stylized, artsy form. Both films can also be criticized for their epic length; Aster’s is languid throughout, and Kent’s tends, in the final stretch, to meander and lose clarity (the editing is by Simon Njoo).

From the opposite point in the spectrum, one might also question the note of hopefulness that Kent brings to her film at the close, not only in terms of an episode in which an elderly English settler shows kindness to Clare (and especially Billy) even as others are engaged in what can only be seen as mass executions of indigenous prisoners, and in the final sequence on a sun-drenched beach, which takes advantage of Ganambarr’s dancing skills but adds a poetic touch that comes across as being rather at odds with the grim realism that’s prevailed to that point, although some viewers may appreciate the hint of possible light in the darkness.

Still, Kent’s work is the superior film of the two, because it is not merely about the deployment of horror tropes in service of a weak storyline. “The Nightingale” is horrifying because it so powerfully portrays the deepest recesses of inhumanity, in terms of both men’s treatment of women and the brutality of a conquering race against peoples they dismiss as inferior.