Stripped down to its grizzled, unapologetic essentials, "Logan" is unlike all previous "X-Men" films (and, it should go without saying, the inferior spin-offs, 2009's "X-Men Origins: Wolverine" and 2013's "The Wolverine"). Less superhero actioner than semi-arthouse road saga, this ultraviolently R-rated and exceedingly morose turnabout gives Hugh Jackman (2015's "Pan"), who is said to finally be retiring from playing long-suffering, knuckle-clawed mutant John Logan, a logical if purposefully unpleasant send-off. What writer-director James Mangold (2005's "Walk the Line") and co-writers Scott Frank (2008's "Marley & Me") and Michael Green (2011's "Green Lantern") lack in imagination they frequently make up in raw, end-of-the-line grittiness.

The year is 2029, and a weathered Logan (Hugh Jackman) now lives his life laying low, working as a limo driver near the Texas-Mexico border while caring for the ailing Charles Xavier (Patrick Stewart). It is believed mutants are a dying breed—the last one was purportedly born 25 years ago—but this presumption is proven wrong when young Laura (Dafne Keen), who shares his powers and genetic makeup, walks into his life. With the help of nurse Gabriela (Elizabeth Rodriguez), she has escaped from a nefarious testing facility manufacturing child mutants and is now on the run. Logan reluctantly accepts an offer of twenty grand to transport Laura to a mythical safe haven in North Dakota—one read about in "X-Men" comics—but their journey will be an arduous one with no guarantee of solace at their destination point.

If "X-Men" has always been about the responsibility that comes with having extraordinary powers and the adversity faced by those who are viewed as different (what is it if not a metaphor for real-world discrimination and LGBTQ rights?), "Logan" has more existential fish to fry. With their best years behind them and nearly everyone they've ever cared about gone, John Logan and Charles Xavier are facing nothing less than their own mortality. Logan doesn't think much of kids, but as he and Laura connect in unexpected ways during their trip he sees in her a newfound hope—not necessarily for himself, but for the future of the mutant population and maybe even the world as a whole. When he's gone, there will be others to carry on his legacy. It's a dramatically potent notion, and it only gradually sneaks up on the viewer.

At this point, Hugh Jackman knows Logan front and back, and here he plays him as weary, broken, and bitter. His warming-up to Laura is slow and steady, their bond complicated but irrefutable. Jackman saves his best moments for last, and they are a knockout, arguably better than anything that has come in the two hours prior. As Laura, newcomer Dafne Keen impresses with what may be the most difficult role. Without the use of her voice—she does not speak for much of the film—Keen must express herself in other ways, and the tough emotional places she ultimately goes hold the nuance of an actor far older than she. The always invaluable Patrick Stewart (2016's "Green Room") gives Charles Xavier a newfound vulnerability, alternating between curmudgeonly, fearful, and wise as he realizes there is no overcoming his deteriorating health.

"Logan" goes light on special effects showcases to narrow in on the human being behind Logan's regenerative abilities and retractable claws. With that said, the film fails to explore how he ended up where he is and what, exactly, has become of his fellow X-Men. The pacing is on the measured side, not quite meditative as much as simply sluggish. The villains, namely Richard E. Grant's Zander Rice and Boyd Holbrook's Donald Pierce, are largely forgettable with little for which to remember. Action set-pieces are few and far between, but when the fight sequences arise they pack a merciless, no-holds-barred punch. To be sure, the refreshing R-rating is used to its fullest, never holding back from the brutal reality of what is occurring.

"Logan" isn't a quote-unquote "fun" movie. It demands a certain amount of patience and an open mind, particularly from fans who may never be able to view the previous "X-Men" features in quite the same way. It is well-made and thoughtful, however, and it pays off so splendidly in the final fifteen minutes one wishes what preceded this climax could have been its equal. Where "Logan" leads is inevitable and necessary, but it doesn't make it any easier. With its powerful concluding image, one gets the sense a final stamp has now been placed on not just the Wolverine character but the "X-Men" series as a whole. By taking so many defiant chances, how would it be possible to turn back?