Killers of the Flower Moon is a serious film — a handsomely made film on an epic scale and certainly a somber and thoughtful film on a harrowing subject. This is a rare enough experience in American cinema to make it a must-see for anyone remotely interested in film. And for many who are calling it a certified Martin Scorsese masterpiece, it has a huge emotional impact.

And I wish I’d experienced it that way. Instead, I found it oddly subdued and constrained. Which perhaps it has to be, given the subject matter. Still, that makes it somewhat disappointing for me. After all, when I’m hearing about a Scorsese masterpiece, I’m expecting to stagger out of the theater feeling almost unstrung in the best possible way, because this is the filmmaker who brought us Goodfellas (1990), Raging Bull (1980), King of Comedy (1982), and Taxi Driver (1976), just to name my personal top four Scorsese achievements. His has a uniquely spectacular career spanning over half a century now.

Based on the best-selling nonfiction book by David Grann, Killers of the Flower Moon: The Osage Murders and the Birth of the FBI, Scorsese’s adaptation shifts the focus away from investigator Tom White, the agent sent by young J. Edgar Hoover to inquire into the dozens of murders of oil-rich Osage Nation citizens in 1920s Oklahoma. Originally, Leonardo DiCaprio was set to star as White. But rightly perceiving that their initial approach to the script would play as an all-too-typical white-savior narrative, Scorsese and cowriter Eric Roth (Dune, The Insider, A Star Is Born) opted to shift the focus away from White (ultimately very well played here by Jesse Plemons), pushing his arrival in the Osage Nation to the last third of the three-and-a-half-hour film.

Working intensively with Osage consultants, Scorsese and Roth decided to focus their screenplay instead on a central love story between Mollie and Ernest Burkhart, an Osage woman of wealth, and the white WWI veteran who marries her and gets drawn into an ever-deadlier plot to deprive her and her family of their holdings through cold-blooded murder. As Mollie, Lily Gladstone is magnificent in her grave self-possession, her glints of humor, and her immense accumulating grief. As Ernest, Leonardo DiCaprio throws himself into a role more typical of Scorsese films — the offbeat, amoral striver with no aversion to crime or violence.

But Ernest is much more dim-witted than Scorsese antiheroes generally are. From the beginning, he’s under the thumb of his seemingly amiable but rapacious uncle, William Hale (Robert De Niro), who likes to be called “King,” as in the “King of Osage County.”

There’s no mystery about “King” Hale — from the beginning it’s clear he’s a variation on Scorsese’s mobster kingpin characters. In this case, he’s running a widespread local racket that preys on the oil-rich Osage citizenry while positioning himself as simply a kindly benefactor who builds schools and medical facilities for them, even learning their language. Ernest, weak-willed and easily cowed, is immediately drawn into Hale’s plot to get ahold of Mollie’s oil rights by having him marry into her family. But because Ernest is also romantically drawn to Mollie right away — and their marriage is, strangely, a mutually affectionate one — he obscures in his own mind the brutal henchman role he plays in Hale’s schemes.

It’s an insightful portrait of the nature of intertwined racism and capitalist predation, this refusal to recognize one’s own hateful deeds. In the end, Ernest can admit to all his evildoing except his central betrayal of Mollie and the lies his own household is built upon. In willfully blind disavowal, he’s only eclipsed by his uncle. Even after Hale’s entire murderous scam is exposed, he’s writing long, rationalizing letters from prison to his old “friends” in the Osage Nation.

Hale seems to convince himself — or at least, he certainly appears to convince Ernest — that they have a cruel-to-be-kind responsibility to relieve the Osage citizens of their land rights. He argues that these people can’t “do” capitalism, don’t really understand money the way whites do. Plus they tend to be sickly — diabetes is rampant in the community, for example. Mollie as one of the many sufferers, which exposes her to the corrupt “treatments” pushed by Hale and a pair of doctors who are, alarmingly, also undertakers — treatments administered by Ernest himself.

Clearly, Hale argues, their day is done. By this logic, it’s a mercy to push them toward extinction a little quicker.

Since none of this is mystified or withheld from the audience — from the beginning, we see the plotting, the hiring of henchmen, the murders as they happen — the central mystery of the film is how Mollie fails to recognize, or refuses to recognize, Ernest’s role in this mayhem. She’s presented as a savvy woman, who knows Ernest’s character immediately: “Coyote wants money,” she says, not in alarm but with worldly amusement. She lives in an Oklahoma boomtown, after all. The streets are teeming with hustlers and hucksters, and her own wealthy family is very appreciative of the “nice things” their oil money has brought them. Why should Ernest be any less acquisitive?

But as the killers take aim at her own sisters, she’s the one who hires a private investigator and eventually goes to Washington to put in a personal plea for help. We’re left to assume she simply can’t bear to look for the culprit in her own home.

This “assuming” I mention is due to our limited access to Mollie’s thoughts, at least compared to Ernest’s. The workings of his mind are laid bare, while hers are cloaked in opaque silence. That too was a decision made by Scorsese and Roth, after they became concerned that, in early drafts of the screenplay, they were “putting words in Mollie’s mouth” in a way not justified by the historical record.

Even at the climactic point, following trial scenes that make Ernest’s role in the murders and her own poisoning clear, we are denied even an extended reaction shot from Mollie showing her face as she registers the full extent of Ernest’s betrayal. This seems to represent Scorsese and Roth’s most earnest attempt to hold off from too-definite attempts to represent Mollie’s mental state, and certainly the care they’re taking, and their apparent awareness of the various ways that they, as white men, could impose their own reality on an Osage woman in a way that’s untrue or offensive.

It’s impossible to argue that they should’ve been any less careful, if they were going to make the movie at all. And there are those who lament that they did, when an Osage creative team taking the screenwriting and directorial lead would’ve made an entirely different movie. Or when there’s another book dealing with the Osage murders, the 1991 novel Mean Spirit by a Native American named Linda Hogan, who’s Chickasaw. It was even nominated for the 1991 Pulitzer Prize for fiction.

But even while acknowledging that the project requires special care, carefulness itself seems to work against Scorsese’s most exciting directorial strengths. Was he being careful when he shot the legendary, frenetic, paranoid, coke-fueled, “Don’t forget to stir the sauce” sequence in Goodfellas? Or the climactic boxing match of Jake LaMotta versus Sugar Ray Robinson in Raging Bull, with its horrifying, blood-flying, slo-mo violence as Robinson batters LaMotta to a pulp, ending in LaMotta’s slurred but still defiant line, “You never got me down, Ray”?

Killers of the Flower Moon is an admirable, stately film, but not a mindblower if you know anything about the history of American genocide and the long, grisly, concerted effort to eradicate Native Americans. Scorsese likes to say of films that have immense power that “the emotion is in the emulsion.” But here, the emotion isn’t really in the emulsion. If it’s anywhere, it’s in the first-time discovery of details of the Osage murders, if you don’t happen to know anything about them.

Scorsese makes a bold move late in the film, when he shifts abruptly to a denouement set in a 1950s radio station in the midst of a production of a live true-crime broadcast about the Osage murders. Shot garishly in contrast to the subdued natural tones of the rest of the film, it’s a radio show made by white performers providing inane melodramatic narration and acting, and overdone sound effects, for the amusement of an all-white audience. It’s a further mea culpa from Scorsese, indicting his own complicity as a white filmmaker presenting this film, as well as our complicity as an audience, presumably majority white, who are watching it.

You no sooner realize this before Scorsese himself steps into frame to read the final summation of Mollie’s life story. Though he alone among the radio performers narrates gravely and sensitively, there’s no doubt he’s still part of this entertainment, as we are as well.

So, once again, the effect is subdued, somber, and self-conscious. Any wildness or brilliant controlled chaos reminiscent of Scorsese’s best cinematic work is kept to the margins.

Actors in smaller roles are unleashed in brief, disturbing, and sometimes hilarious scenes. Cara Jade Myers as Mollie’s sister Anna Brown is drunkenly raucous and funny even as she’s being murdered by incompetent goons who are trying to shoot her while she’s sitting upright — only they can’t get her to sit upright. Louis Cancelmi as bug-eyed Kelsey Morrison, an accomplice of Hale and Burkhart’s, does a marvelous off-the-wall dance at Ernest and Mollie’s wedding and later tries to get information from an insurance agent about how he can best insure an Osage person in order to murder her, then adopt and murder her children so as to collect the money. And Ty Mitchell as John Ramsey, another Hale accomplice, but this one a downtrodden sodbuster with eight kids who groans every time Burkhart enlists him in another murder. He looks so ill-used and beaten by life, with his gaunt, seamed face and one opaque eye, it hardly seems possible he’s just an actor. Turns out he’s an actor now, but before that he was a cowboy, a small-time rancher, a Navy seaman, an oil rig firefighter, and a lot of other professions that do bodily damage.

But never mind. Even these bright glints of old wild Scorsese, shining in the muted tones of careful and still admirable new Scorsese, are well worth seeking out.