Think back to those first few moments of Trainspotting, where Ewan McGregor races headlong through the streets of Edinburgh to the pounding beat of Iggy Pop’s “Lust for Life.” Or how about that terrific set-piece that kicks of 28 Days Later, where Cillian Murphy wanders through a deserted London wondering whether he’s the last man in the world. Even lesser entries in Boyle’s canon like A Life Less Ordinary, The Beach and Slumdog Millionaire open with scenes that bristle with the director’s energy and wit.

127 Hours is Boyle’s most contained film yet, unfolding largely in a single location with a single actor over a brief five-day span. And, yes, 127 Hours—which is based on a true story—does sport a terrific opening sequence, one that puts you right inside the head of its main character and gets you pumped for the movie ahead. While the infectious Free Blood techno tune “Never Here Surf Music Again” blasts on the soundtrack, we watch the early morning routine of outdoor enthusiast Aron Ralston (played by James Franco) as he prepares to make the trek to Utah’s Canyonlands National Park for a full day of hiking, biking and canyoneering. Making excellent use of split-screen, Boyle shows Ralston assembling his gear and setting off on his journey alongside images of cheering crowds and the wide-open spaces of the natural playground where he’s headed. The effect is positively galvanizing—you experience the same anticipatory excitement that Ralston feels as he approaches his destination.

That energy increases tenfold when he hops onto his bike and tears off through the Canyonlands, a merry adventurer with no deeds to do or promises to keep. He’s drunk on the freedom of being alone in the wild; even when he takes an accidental header off his bike, he sits up laughing. After all, getting banged up is part of the fun. Coming across a pair of comely co-ed hikers (Amber Tamblyn and Kate Mara, making the most of their limited screen time), he attempts to pass on his geeky enthusiasm for the great outdoors, guiding them to a special underground pool that no hiking guide will tell you about. After that brief dalliance, he’s back on his own, scrambling through a gorge when suddenly he puts his weight on the wrong rock and tumbles down into a crevasse. He lands at the bottom and the stone crashes down on his right arm, pinning him in place. At that moment, the momentum of the previous twenty minutes comes to a sudden halt and we’re stranded there alongside Aron for the remainder of the movie as he desperately attempts to free himself before succumbing to starvation and dehydration.

Prior to the film’s release, many wondered how Danny Boyle was going to make a full-length feature about a guy trapped in a canyon. The thing is, it’s not as difficult a feat as you might imagine. There are numerous narrative devices—flashbacks, hallucinations and the like—that a filmmaker can use to flesh out what would seem to be a thin narrative to hang a movie on. And indeed, Boyle does employ many of these elements during 127 Hours, but he not in a way that feels like egregious padding. Take the flashbacks; another filmmaker might have adopted a This Is Your Life approach, boiling down Ralston’s personal history to a series of key moments, like the first time he put on a pair of hiking boots or the time his dad bought him his first Swiss Army Knife. But Boyle does something far more interesting with the flashbacks. Instead of fully-formed scenes, they are presented as abbreviated moments that appear with no exposition or explanation. Furthermore, they are always triggered by something that’s happening to Ralston in the present. For example, when his free hand is briefly bathed in a patch of sunlight, he remembers a random moment from his childhood when his dad woke him early in the morning so they could watch the sunrise together. The tactile nature of the transitions from the present to the past make these glimpses of Aron’s life seem like living memories rather than scripted flashbacks. (The closest thing we get to a narrative arc in these flashbacks are brief glimpses of the beginning, middle and end of a relationship Ralston had with an ex-girlfriend, who breaks up with him for some of the same reasons that landed him in his current predicament—namely, his lack of foresight and a pronounced loner’s streak.) And as the days pass and his condition worsens, Boyle allows memory bleeds over into reality, which results in the climactic hallucination—or, if you prefer, premonition—that leads Aron to take drastic action in order to escape certain death.

That drastic action has been well documented since Ralston’s story was first reported back in 2003, so I don’t think that it’s a spoiler to reveal that he ultimately frees himself by sawing off his own arm with a dull blade. In fact, some moviegoers might thank me for revealing that particular detail, as it’ll allow them to steel themselves for what is an almost unbearably tense and harrowing scene. The anticipation of his self-amputation is almost worse than the actual procedure—I fully admit to cringing in my seat as Ralston twists his trapped arm until it snaps. Once he’s free, Boyle wisely resists the urge to belabor the story any further; Ralston is found by another set of hikers and airlifted to the nearest hospital. A closing coda depicts Franco leaping into a pool and surfacing to come face-to-face with the real Ralston. It’s a terrific flourish, that plays wonderfully onscreen, sending the audience out of the theater with the same sense of elation they felt in the opening scene. (It’s worth mentioning as well that this is a terrific showcase for Franco, who handles everything Boyle throws at him with aplomb.) Trim and focused without an ounce of narrative fat, 127 Hours is a thrillingly immersive viewing experience, not unlike Trainspotting all those years ago.