Repression, sublimation and their terrible psychic toll ripple through “The Power of the Dog,” Jane Campion’s handsome adaptation of Thomas Savage’s 1967 novel. In 1920s Montana, brothers Phil and George Burbank (Benedict Cumberbatch, Jesse Plemons) tend to their family’s ranch, a prosperous spread whose Gothic main house evokes the windswept romance of a Wyeth painting. But any notion of romance is swiftly extinguished by the toxic emotions seething beneath the Burbank brothers’ household.

During a cattle drive, they stop at a boardinghouse run by a fragile, refined widow name Rose (Kirsten Dunst) and her delicately weedy son Peter (Kodi Smit-McPhee). At dinner, when Phil finds out that Peter made the frilly paper flowers that adorn the tables, he taunts the boy with gleeful cruelty. He’s a mean, manipulative and emotionally sadistic caricature of masculinity, traits that come into florid focus when George proposes marriage to Rose and brings her into the strained, increasingly strange Burbank family circle.

Although “The Power of the Dog” is a Western, with all the riding, wrangling, sweeping vistas and kink-tastic leather wear that the genre demands, Campion leans into the psychological horror of the monster who haunts George and Rose’s married life: With Peter away at school, it falls to Rose to endure Phil’s wanton acts of viciousness and spite. When she begins playing the piano again, he ridicules her efforts, making sure to whistle a tune that she stumbles over whenever she’s in earshot. (Jonny Greenwood’s musical score accentuates the creeping sense of unease with suitably unsettling dissonance.)

Exquisitely filmed by cinematographer Ari Wegner, “The Power of the Dog” exerts a dreadful tidal pull of doom and endangerment. Framing the gorgeous scenery through windows and doors (Montana is played by New Zealand), she and Campion have found an intriguing visual language to reflect the film’s themes of concealment and potentially disastrous disclosure, fully embracing the wide-open expanses of western landscape, but also restricting and containing it. Grant Major’s production design possesses the same push-pull energy: stately and simple on one hand, minutely detailed on the other.

Rose’s victimization and decline – and George’s passivity – too often feel perfunctory, driven by the necessities of plot rather than human nature. But once Peter arrives at the ranch during a break from his medical studies, the story deepens in ways that are revelatory, disturbing and, finally, perversely triumphant. “The Power of the Dog” is an ensemble piece in which all the actors are working at the top of their game (even if Dunst is given relatively little to do except look desperate, dissipated or both).

But this is Cumberbatch’s movie, one in which he invests his character with just the right degree of menace, casual erudition and unconscious grief. It might not take long for present-day audiences to figure out what’s at the core of Phil’s rage, especially when Peter comes into his orbit, but there’s still suspense to be found in just how the two men wordlessly navigate the shifts in power and perception that define their ambiguous bond.

That bond has to do with how Phil and Peter define manhood and the lengths to which they’ll go to live up to it – a groundbreaking theme in the 1960s that is just as germane now. The title of the “The Power of the Dog” refers to the shape of a mountain near the Burbank ranch and who has the ability to recognize it. Once again demonstrating her own strong, clear vision – not to mention superb control of her craft – Campion proves her ability to illuminate hidden truths and let us see what was hiding in plain sight all along.