Stately, austere and somewhat soap operatic, “The Power of the Dog” is an intimate story in a Cinemascope setting, and marks a welcome return to feature films for New Zealand’s Jane Campion, director of “The Piano” and most recently (in 2009) “Bright Star.”

Netflix has given her a big canvas and great cast for another tale of repressed desire, emotions and sexuality, her specialty.

Based on a Thomas Savage nove, “Dog” is a 1920s saga set in Montana, the story of two brothers, the widow one marries and the son that comes with that marriage. And even if it doesn’t manage many surprises, it’s still an acting showcase for Benedict Cumberbatch, going larger-than-life, and Kirsten Dunst, quietly underplaying against that.

Cumberbatch and Jesse Plemons play brother ranchers, the Burbanks. The oldest, Phil (Cumberbatch), is a grizzled cowman who throws his weight around, hangs with the ranch hands and avoids bathing at all costs. And with his first words he gives away much of his character, just interacting with his more subdued, genteel sibling, George.

“Hey, Fatso!”

Phil is a bully. And George lets him be one. He accepts second-banana status to the cattle-savvy, more macho Phil. He takes Phil’s abuse about being “a chubby know-nothing too dumb to get through college.” Because to some degree, it’s true. Phil gives hints of his superior intellect, referring to themselves as “the Romulus and Remus and the wolf who raised us” when talking about the cattleman, the fabled “Bronco Henry,” who taught them how to run a ranch.

George dresses more like his class, even when they’re taking their herd to town to sell. George is soft-spoken. George bathes.

And when Phil’s bullying makes the widow Rose (Dunst) who runs a boarding house and restaurant, weep, when Phil insults her thin, artistic son Peter (Kodi Smit-McPhee), George is the one to makes amends.

George is also the one who sets his cap for Rose, and we see the brothers — who shared a room in their big, two-servant house on the plains — drift apart.

The split is deftly-captured in just a couple of scenes and the chill between them comes out in a single sentence, a piece of news Phil wasn’t privy to.

“We were married Sunday.”

Thus does “The Power of the Dog” set us up for a cruel war of wills, with smart and condescending Phil never missing a chance to humiliate the “cheap schemer” new bride to her face, even encouraging the ranch hands to pick on the fey and delicate med student, Peter, aka “Little Lord Fauntleroy.”

Cumberbatch’s bluff and blustery bully seems studied, measured and calculated. On purpose.

Plemons gives us a another performance of soft tones and quiet kindnesses. He’s equally invested in making George a non-confrontational figure, somebody who’s used to “handling” his arrogant, banjo-picking alpha male brother.

Dunst gives us quiet suffering, a woman who accepts her lot and the improved prospects for her boy that a marriage provides, but who swallows her misery from a bottle — beaten down by a brother-in-law who not only knows how to spell “misogyny,” he lives it.

Smit-McPhee, a child star since “Let Me In,” gets across all we need to know just with his physicality. Everything about Peter screams “delicate.”

That points to the shortcomings in Campion’s slow-moving melodrama. “Netflix editing” is what we call it when films or series are padded, layered with onscreen fat that prevents the picture from developing anything like the necessary pace to pull us into the story.

And that’s important in “The Power of the Dog” because of the tropes it trots out that give away its “secrets” at first glance. When we know much of what’s coming, dawdling along the way makes characters and incidents play as pre-ordained, dulling their impact.

Cumberbatch’s portrayal becomes classic “over-compensating,” the way Hollywood has long depicted characters with a serious “He Man Woman Hater’s Club” streak.

Smit-McPhee’s Peter is more stereotype than archetype.

Even if some of the second and third act twists upend some expectations, even if the Big Sky setting (it was filmed in New Zealand) promises “epic,” the melodramatic characters and touches give it a predictable familiarity.

It’s great to see Campion making movies again, and if Netflix writes blank checks to cinema grand masters like her, Scorsese, Cuaron and others, that’s money well-spent and a service to the arts far beyond what cable services like HBO ever offered.

But given their heads, every single established director who has worked for Netflix has been flattered into making big, flaccid epics that viewers can leave on while they take bathroom breaks or make a dash to the kitchen. “Streaming” and “slow” shouldn’t be synonymous.

Rating: R, for brief sexual content and full nudity

Cast: Benedict Cumberbatch, Kirsten Dunst, Jesse Plemons, Kodi Smit-McPhee and Keith Carradine.

Credits: Scripted and directed by Jane Campion, adapted from the novel by Thomas Savage. A Netflix release.

Running time: 2:06