Scott Cooper’s stately, intense Western depicts a long, dangerous trek from New Mexico to Montana, but it’s the emotional journey of its protagonist—from utter hatred of Native Americans to respect and admiration for them—that’s the real subject of the film. Adapted by writer-director Cooper from a treatment by the late screenwriter Donald Stewart, “Hostiles” contains some brutal action scenes, but its focus is on character, and while its message is not a subtle one, Cooper’s slow, somber delivery of it proves quite effective.

In one of his more restrained recent performances, Christian Bale plays Captain Joseph Blocker, a hardened Civil War veteran now stationed at Fort Berringer, a remote outpost in New Mexico. The year is 1892, as the Indian Wars are winding down, and he is ordered by his commander Colonel Biggs (Stephen Lang) to undertake a mission he detests: escort Yellow Hawk (Wes Studi), a former Cheyenne war chief who has been in custody for years but is now dying of cancer, along with members of his band—among them his son Black Hawk (Adam Beach) and Black Hawk’s wife Elk Woman (Q’orianka Kilcher)—to their tribal lands in Montana so that the old man can die in peace.

Having once nearly been killed in battle with Native Americans, Blocker believes that, as the terrible old adage would have it, the only good Indian is a dead Indian, but under threat of court-martial he saddles up for the journey, taking along his old friend Sergeant Thomas Metz (Rory Cochrane), by-the-book Lieutenant Rudy Kidder (Jesse Plemons), Buffalo Soldier Henry Woodson (Jonathan Majors) and callow young Private Philippe DeJardin (Timothée Chalamet).

Along the way the troupe is increased by a couple of unwanted additions. One is Rosalie Quaid (Rosamund Pike), the sole survivor of a family of homesteaders who have been slaughtered—in a very explicit opening sequence—by a band of rampaging Comanche warriors. Blocker intends to leave the traumatized woman, who initially reacts with horror to the presence of Yellow Hawk and his family, at Colorado’s Fort Collins, but she insists on continuing the journey. Even more problematic, Blocker is persuaded by the base commander Lt. Col. McCowan (Peter Mullan) to take charge of Sergeant Charles Wills (Ben Foster), a prisoner who has gone on a rampage and slaughtered Native Americans indiscriminately, and transport him for trial.

By this time Blocker’s attitude toward Yellow Hawk is changing. The chief and his followers joined with the soldiers to hold off the Comanche raiding party that massacred Quaid’s family—an encounter that reduced the size of his squad—and have dealt considerately with Rosalie. Blocker also finds it increasingly difficult to dismiss the more progressive attitudes toward the Indians voiced by, among others, McCowan’s wife (Robyn Malcolm). The addition of the savage Willis to the group, moreover, draws a contrast he cannot ignore, forcing him to confront his own bias.

By the time what’s left of the group reaches Montana—there are further gruesome reductions along the way—Blocker, and Rosalie as well, are insistent that Yellow Hawk be given the traditional tribal send-off he longs for. That, however, is something that a grizzled land baron (Scott Wilson), who now claims the territory as his own, is determined to prevent. The resultant stand-off will test how much Blocker—and Rosalie—have changed.

As a tale of a man’s gradual transformation from bigotry to enlightenment, “Hostiles” is laudable, the obviousness of its message—only magnified by a final scene between Blocker and Woodson—mitigated by Bale’s tightly controlled performance and by the moody, reflective ambience Cooper and his cinematographer Masanobu create, managing to make even the wide expanses of the Western plains and forests feel emotionally claustrophobic. Pike adds further depth to the proceedings, morphing from a helpless, terrified victim to a strong-willed woman with considerable nuance. And while Foster chews the scenery with abandon, the other members of the supporting Caucasian cast generally share Bale’s understatement. (It might be noted, though, that if this were the only film in which Chalamet were featured this year, there would be no mention of any “breakthrough” on his part. He’s perfectly fine, but has very little to do, disappearing from the ensemble fairly quickly. Without “Lady Bird” and “Call Me by Your Name,” few would note his presence here at all.)

While the film succeeds on that side of the equation, however, its treatment of Native Americans lacks subtlety; they are portrayed either as supremely noble and stoic—as is the case with Yellow Hawk, Black Hawk and their fellows—or maniacally savage (e.g., that Comanche raiding party). There is no middle ground, no mixture of virtues and flaws, no shading of the sort one finds among the white characters. That isn’t to say that Studi, in particular, doesn’t bring an air of dignity to Yellow Hawk; he is the very model of the upright, courageous leader, hiding the pain wracking his body. But the actual conception has not advanced much beyond Chief Dan George’s Old Lodge Skins in “Little Big Man”—minus the genial humor, of course.

Epic in length, deliberately paced and shot through with bursts of graphic violence, “Hostiles” is in many respects a grueling experience, but overall a worthwhile one.