Martin Scorsese’s Killers of the Flower Moon isn’t a whodunnit; in fact, it’s closer to a who-didn’t-do-it. We know from the very beginning who is responsible for committing the brutal serial murders of wealthy Osage Native Americans in 1920s Oklahoma that the film chronicles: pretty much every single one of their white neighbors, spearheaded by William Hale (a skin-crawling Robert De Niro). Scorsese, most often associated with mafia stories, stealthily suggests here that the most dangerous gang of all is the one into which all these perpetrators have been born. That’s an idea he investigates through the confused loyalties of Leonardo DiCaprio’s Ernest Burkhart, the Judas-like husband of Mollie (movie-stealer Lily Gladstone), an Osage woman who owns lucrative oil headrights that William wants to fatten his own pockets with. This searing epic — based on a harrowing chapter of real American history — is an unsparing and self-implicating look at complicity and greed in the eye, a monumental movie that cements its maker as one of the greatest to ever do it.

There are so many standout elements we could draw attention to here: Gladstone’s gravitational performance, the incredible richness of the ensemble (largely made up of Osage Nation members), the breathtaking final scenes. But it might be more prudent to address head-on what is arguably the biggest obstacle to hitting that play button: the movie’s three-hour-plus duration. Fear not, though: editing titan Thelma Schoonmaker — along with the propulsive force of the performances, music, and cinematography — ensures the film keeps such a tight hold on our attention that we never feel the runtime drag, not even for a second. We’re truly in the hands of masters here.