In the opening scene of 127 Hours, director Danny Boyle showers the screen with images of various groups of humans going through the hustle and bustle of everyday life; passengers pack into subway cars like sardines, pedestrians walk shoulder-to-shoulder down sidewalks and spectators cheer at crowded stadiums.

These loud and cramped moments exquisitely contrast the quiet isolation that will soon sweep over Aron Ralston, a real-life thrill-seeker who got his hand trapped beneath an immovable boulder while trekking alone through Utah's Canyonlands National Park in 2003.

Unless you have been living in a cave for the past several years I'm sure you've heard of Ralston's courageous story, but in case you haven't, you might want to stop reading right now.

If you're still here, then I don't need to tell you that Ralston, after waiting for nearly six days, severed his own arm with a dull knife to free himself and escape to safety. But I said it anyway and it's even worth mentioning again: Ralston cut off his own frickin' arm with a dull knife to survive.

I guess I felt the need to say that once again so you could have more time to think about what you would do under the same circumstances. People are capable of accomplishing amazing things under extreme adversity, but could you bear to hack off your own limb? Could I do it? I'm afraid it's impossible for me to provide an answer at this time.

But in the grand scheme of things, my response isn't terribly important. I'm assuming the only reason you are perusing this review is to find out if Boyle is able to create a film about a guy who spends most of his time in the same confined space and make it enthralling.

That, my readers, I can answer with no problem at all. But if you had to ask that question, then I presume you are not too familiar with the work of Boyle, the Academy Award-winning director of Slumdog Millionaire, 28 Days Later and Trainspotting.

Any other filmmaker would have probably taken a minimalist approach in crafting 127 Hours, but Boyle uses his signature kinetic style and visual prowess to make the film seem as enormous as the Chrysler Building.

Boyle, with the aid of cinematographers Anthony Dod Mantle (Slumdog Millionaire and The Last King of Scotland) and Enrique Chediak (Repo Men and The Boiler Room), beautifully captures the colorful landscapes of the Utah national park, but he also utilizes the vast and rugged terrain to exhibit just how cut off from human contact Ralston (James Franco) is when he falls through a crevice in the Earth and gets pinned by a large rock.

And once Aron settles into his unfortunate but temporary home, Boyle and Simon Beaufoy's (Slumdog Millionaire and The Full Monty) screenplay, which is based on Ralston's memoir, Between a Rock and a Hard Place, uses flashbacks, hallucinations and premonitions to reveal everything that is going through our hero's head as he stares the Grim Reaper directly in the face. (A trippy montage of soda advertisements that is shown when Aron is dying of thirst is both effective and amusing.)

As one would expect, 127 Hours hits a few slow spots as Ralston gets closer and closer to death, but the film recovers any suspense it lost when he makes the desperate decision to amputate his arm with a knife so blunt it couldn't slice through a sheet of paper.

These scenes could have easily been filled with gratuitous blood to get a reaction out of the audience, but Boyle wisely displays the blade slicing the skin in fleeting segments. That way we are given the opportunity to use our own imagination, which actually makes the situation all the more harrowing. (It's a good thing no one was sitting near me because those sequences left me squirming in my seat so bad I'm sure I looked like a fish thrown out of water.)

But as much praise as Boyle deserves for putting the pieces in the right places, 127 Hours is essentially just a one-man show, and it all belongs to Franco (Pineapple Express and Milk), who absolutely owns it. Franco is genuinely funny as he portrays Ralston's initial cocky and fearless attitude, but he really gets to shows his incredible range when Aron's mental and physical health start to deteriorate. And it's extremely heartbreaking to watch Franco's performance as Aron reflects upon his life and uses his video camera to leave messages for the family members he's taken for granted over the years. Franco's acting alone is enough to make you want to call those closest to you as soon as you walk out of the theatre to tell them how much you love them.

As 127 Hours proves, you truly never know which moment will be your last.