In “Captain Fantastic,” Viggo Mortensen stars as a left-wing survivalist raising six children in the Pacific Northwest. Photograph by Erik Simkins / Bleecker Street

There’s something perversely ingenious about the writer and director Matt Ross’s independently produced feature “Captain Fantastic,” which opened in limited release a few weeks ago and is now playing nationwide. It is an independent film that seems to be as meticulously calculated to meet the expectations of its audience as any studio-made intergalactic adventure. Though it’s not an especially good movie, it’s a very skillfully constructed one, and it runs on a fantasy that’s as persuasive and as credible to its target audience as comic-book adventures are to a different viewership. For that matter, the title “Captain Fantastic”—which is comically but intentionally misleading—even suggests, with a self-aware bravado, Ross’s precise calibration of the movie to his audience’s counter-superheroic expectations.

“Captain Fantastic” is the story of a left-wing survivalist, Ben Cash (Viggo Mortensen), martial and authoritarian yet soft-spoken and good-humored, who’s raising his six children (ranging in age from about six to eighteen) in an isolated compound somewhere in the deep woods of the Pacific Northwest. He teaches them to catch and slaughter some pretty big animals for meat; he gives them rough training in hand-to-hand combat; he forces them to undertake dangerous climbs on vast rock cliffs; he wakes them up with bagpipe reveille and forces them into immediate calisthenics. He raises them to conceive and accomplish “missions”—for instance, when they’re on the road and need food, he joins them in “Mission: Free the Food,” which is an elaborate plot to steal groceries from a supermarket, involving a bank-robber-level discussion of escape routes.

Ben homeschools them with classic literature of the arts and sciences and stringently teaches them both to memorize and to think critically. He also propagandizes them to reject, totally, the premises and functioning of modern society—he rejects organized religion, consumerism, moralism, pop culture, supermarket food, diner food, and the compromises of big politics. Far from being a moralist, Ben is extremely frank with his children about sex in particular and pleasure over all; the family is no sex cult, there isn’t a hint or whiff of impropriety about them, but there isn’t any shame or fear of sexuality or nudity, either.

Ben swears by the gospel of Noam Chomsky—instead of Christmas, the family’s big holiday is Noam Chomsky Day, at which time he gives his children gifts (hunting knives and crossbows) while they intone his homemade song of praise to “Uncle Noam.” On the other hand, Ben doesn’t go into the full Trilateral-Commission-and-Bilderberg-conspiracy rant; he cautions his eldest son, Bodevan (George MacKay), a self-described Maoist, that Marxists are also capable of evil; and, despite the quasi-military training and discipline that he imposes on the children, he preaches a doctrine not of violent revolution but of mere self-reliance. Meanwhile, the children—particularly the two eldest—engage in a vague push-and-pull with Ben, and with each other, regarding their hermetically sealed upbringing.

The drama is sparked by the absence of Ben’s wife and the children’s mother, Leslie (Trin Miller). Leslie suffers from bipolar disorder and has been staying in a hospital near the lavish home of her prosperous suburban parents, Abigail (Ann Dowd) and Jack (Frank Langella). When Leslie commits suicide, her parents plan a traditional funeral, against her express wishes—and Jack, who blames Ben for Leslie’s trouble, won’t allow him to attend the church service. Yet Ben defiantly organizes the children for a road trip aboard their bus (which is named Steve) to crash the funeral.

Ben tells his children that they’re not supposed to mock anyone else’s beliefs or ideas—except for organized religion. There’s an extraordinary scene in the movie—indeed, the key scene—where the family, travelling aboard Steve, is confronted by a hostile police officer who’s on the verge of arresting them on grounds of truancy—until the children pretend with a persuasively ecstatic enthusiasm to be ultra-conservative Christians whose homeschooling inculcates their love of Jesus, upon which the officer lets them go. It’s the mirror image of the actual Cash family, and it’s exactly the image that the movie’s independent-film audience, liberal and secular, is ready to reject with fear. The idea of Ben as a right-wing survivalist, teaching his children the evils of secularism, Judaism, Islam, abortion, homosexuality, sex outside marriage, the I.R.S., and the National Park Service, would be enough to throw the movie outside the realm of hearty entertainment and into the realm, for its viewership, of a horror movie.

Instead, Ross delivers a schematic but high-relief drama, constructed around the travelling family’s confrontations with the society they’ve spurned—including one batch of concentrated clashes involving the family of Ben’s sister, Harper (Kathryn Hahn), and another involving their decisive conflict with Jack. The film’s strong and simple dramatic backbone sustains a wide range of incidental events that arise from the premise and fill in the background of the story and the characters with a cleverly calculated precision. What’s more, Ross, a longtime actor (he was in Whit Stillman’s “The Last Days of Disco”), makes “Captain Fantastic” an admirably actorly movie. He assembles a remarkable cast, from the name actors playing the grownups to the relatively unfamiliar yet notably adept group playing the children, and he shapes their performances to a pointed aptness that seems to make the script leap from the screen.

“Captain Fantastic” packs many of the virtues that mark the most notable and enduring cinematic fantasies. What Ross stints on is exactly what most cinematic fantasies lack—a grounding in practicality. Despite the bloody killing of a deer in the wild, the animal gets gutted invisibly, and, though the family’s larders are filled with homemade goods, there’s no sense of the sheer drudgery of rustic survival; nobody has any more inner life or outer expression of it than the plot requires. Dialogue fits character and character fits action with an airtight precision that allows nothing from the outside to penetrate the filmmaker’s conceptual structure. Much of the action takes place out of doors, often in spectacular natural settings, which are captured in luminous images that have all the urgency and incisiveness of postcards and posters. The movie’s action is recorded and decorated by way of a camera—the images transmit, they don’t exist. But what they transmit is remarkably coherent.

“Captain Fantastic,” which premièred at the Sundance Film Festival, in January, is conceived not in terms of symbols or experiences or even drama but as a series of emotional tugs and jolts intersected with its ideological sympathies and conundrums. It gratifies its chosen audience in some places, pokes them gently in others. Despite its ostensible countercultural vibe, it lives up to its title—it really is, in its construction and its affect, a superhero movie in live-action form. If independent filmmaking, in its Sundance variety, is like the minor leagues where talent awaits its call-up to Hollywood, Ross has succeeded superbly: he is entirely ready for his shot at a big-budget action movie, for better or worse.