Montana, 1925. The Burbank brothers, Phil (Benedict Cumberbatch) and George (Jesse Plemons), have recently taken over the family ranch and are adjusting to their newfound wealth and status in vastly different ways. George, naturally less inclined toward manual labour, instantly takes to indoor bathing, fine suits, and motor cars. Phil enjoys the sway his new position affords him but rejects its finer trimmings – he staunchly lives the life of a cowboy, refusing to wear gloves even as he castrates livestock, and stalking their enormous manor house in chaps and spurs like a disgruntled ghost of the prairie.

Phil is also a bully and a tyrant. He torments his younger brother and presides over his ranch hands while pontificating about times when men were ‘real men’. When the brothers and ranchers dine at an inn run by widower Rose (Kirsten Dunst) and her delicate teenage son Pete (Kodi Smit-McPhee), Phil’s immediate targeting of the boy (who makes paper flowers and hangs a tea towel over his arm just so) reduces Rose to tears. George is moved, soon marrying Rose and bringing her and Pete to live at the ranch – Phil’s dominion – setting the stage for a tense, interpersonal standoff between the old ways and the new.

 Kirsten Dunst as Rose Gordon in The Power of the Dog (photograph by Kirsty Griffin/Netflix)

The Power of the Dog spends its second act exploring how these characters may differ from our first impressions of them. The mild-mannered George is a sycophant, eager to roll out his new piano-playing wife to impress the governor (Keith Carradine) despite her anxious protests. In turn, the stoic Rose is quickly driven to drink by Phil’s constant, menacing presence. Meanwhile, Phil has a secret patch of land where he goes to cover himself in mud, swim naked, and meditate, his performative machismo masking an almost monastic relationship with the earth. And then there’s Pete – gangly, lisping, clearly not built for life on the ranch. He is studying to be a surgeon, and takes a surgeon’s eye to the world around him: dissecting rabbits, analysing bird’s nests, calmly removing the flesh from dead cattle. Pete wishes to examine the inner workings of every creature – including, and especially, Phil Burbank.

These days, we understand that most bullies are deeply tragic figures, corrupted by past trauma, repressed desire, or an inability to communicate. We understand that their destructive behaviour is cyclical and often hereditary. This makes Phil a fascinating time capsule, an endling for frontier masculinity. He would rather torture his new sister-in-law than see his brother happy. He would rather burn every cowhide on the ranch than sell them to the local indigenous people. He is loathsome, pitiful, and absolutely captivating. After a decade of smirking superhero antics and wan historical biopics, this is the best performance of Cumberbatch’s career.

Benedict Cumberbatch as Phil Burbank and Jesse Plemons as George Burbank in The Power of the Dog (photograph by Kirsty Griffin/Netflix)

By 1925, we’re looking at the last vestiges of what was once the ‘Wild West’. Any nervous hand-wringing at the appearance of railroads and telegraph poles has given way to bitter resignation as propriety and society encroach deeper into the heartland. The Power of the Dog takes an intriguingly bipartisan approach to this, refusing to romanticise the old ways or demonise the new. Campion eschews overt pastoral glamour, but steers clear of hardline, black-toothed historical realism, presenting the onslaught of time and the blossoming of civilisation with utmost objectivity. And while she may not give us much to work with in terms of plot or dialogue, she offers a wealth of sensory detail we can use to fill in the blanks. Ari Wegner’s gorgeous cinematography rebuffs the temptation of sweeping vistas, favouring fine texture over grand composition. She and Campion are more interested in the rippling muscles beneath a cow’s hide than they are in the distant mountains. And Jonny Greenwood’s score, an acoustic current of lilting paranoia, creates the palpable unease that undergirds the film’s final act.

Phil Burbank believes that ‘a man is made by the odds against him’. What those odds are exactly, Campion seems to be saying, is determined by the time and place of your birth; a king of the Wild West might be a sad punchline a decade later, just as effeminate young men could one day be admired, not mocked. Phil recounts endless anecdotes about his late friend and mentor, Bronco Henry, whose saddle sits in a makeshift shrine in the stables. While we can only guess the true nature of their relationship, it’s clear that Henry taught Phil both his trade and his cruelty. Stubborn as he is, Phil understands that this is how their lifestyle and legacy will live on: through stories. But in his hubris, he fails to realise that these stories are as fluid as the times he lives in – and it’s people like Pete who may yet determine their outcome.

The Power of the Dog (Transmission Films), 126 minutes, is currently screening.