Lynne Ramsay’s third film is a drama about a hit-man for hire, but don’t expect anything like one of the muscular vehicles designed for Liam Neeson or Jason Statham. It’s not surprising that the narrative, loosely adapted from novella by Jonathan Ames, should find its protagonist caught up in a political conspiracy—a standard trope. But the fact that it comes from the idiosyncratic Ramsay, whose previous efforts “Morvern Callar” and “We Need to Talk About Kevin” were rule-breakers of the first order, should indicate that it will depart from the usual genre norms.

Joe, the antihero of “You Were Never Really Here,” is not the fast-moving, highly adept lead in a typical action movie but a lumbering, bearded bear of a man whose preferred weapon is a hammer, which he wields with a surprising degree of ferocity, given his usual lethargic gait, though he can certainly use a gun when required. He’s also a devoted son, caring between jobs for his elderly mother (Judith Roberts). But he’s haunted by memories, shown by Ramsay in hallucinatory visual montages—of childhood abuse and traumatic wartime experiences. No wonder he sometimes takes himself to the edge of suicide, nearly suffocating himself with a plastic bag.

That’s why Joe’s missions always aim at punishing malefactors and helping those they have harmed, in particular those involved in the sex trade and the girls they have seduced or kidnapped. The film opens with his cleaning up the gory remains of his latest kill, and follows that up with a visit to his connection, a sweaty fellow in a run-down grocery. Then he’s offered an especially remunerative job—rescuing the daughter of a state senator (Alex Manette) running for the governorship. She’s fallen into the hands of a pedophile ring with political connections, and her father not only wants her rescued but those responsible for her abuse treated with the brutality they deserve.

Joe sets about earning his money with dogged intensity, and certainly gives his client what he ordered: in extracting Nina (Ekaterina Samsonov) from a dingy brothel, he systematically eliminates with his new hammer each and every one of the guards and patrons he encounters along the way.

But his success is short-lived, because Joe quickly discovers that the villains behind the trafficking are responding with even more ruthless efficiency. He, in turn, will aim methodically to take them all out, no matter how powerful they might be. To rescue this one girl, it seems, will be both her salvation and his redemption—though what that will amount to in each case remains ambiguous.

“You Were Never Really Here” derives from a source that, in reality, is glorified pulp, and like Ramsay’s previous films it represents an attempt to transform rather tawdry material into art. Certainly it’s visually striking. Joe’s raid on the multi-story house in which Nina is being held, for example, is depicted in a series of black-and-white sequences ostensibly shot by security cameras from a distance, muffling the brutality of the hammer blows, and they’re juxtaposed with long tracking shots down hallways that are exquisitely wrought. The final act, mostly set in a well-appointed mansion, is elegantly done. A sequence in which Joe disposes of a body by submerging it in a lake, and drifts deeply under the water himself, dragged down by stones in his pockets, is remarkable.

Ramsay’s care in composition is abetted by Thomas Townsend’s cinematography and Joe Bini’s editing, and the mood she creates is enhanced by another score from Jonny Greenwood very different from his music for “Phantom Thread” but no less distinctive and to the point.

The effect is accentuated by Phoenix’s extraordinary lead performance, which never sinks to hardboiled cliché. In his hands Joe is mercurial not in terms of movement but psychological nuance, shifting economically from tragic pain to professional efficiency, from the dutiful son cleaning up after his mother to the avenging angel who takes on the corruption of the world. Most of the other performances in the film may be little more than utilitarian (apart from Roberts, who’s fearless as Joe’s mother), but Phoenix’s is a mesmerizing turn.

Yet by the time that “You Were Never Really Here” concludes after less than ninety minutes (roughly one for each page of Ames’s book), you’re left wondering why you remain so unmoved, whether it be to sympathy, or revulsion, or anger. To be sure there’s Phoenix’s performance to admire, but in the end it seems to have been generated in service of a film that’s more a visual exercise than a potent drama with something to say about our culture. Comparisons to “Taxi Driver” are almost inevitable, but Ramsay does not achieve a similar catharsis.

Yet it must be acknowledged that hers is a distinctive cinematic voice. In this instance, however, as with “Morvern Callar,” it’s one that seems pitched more to style than substance.