"The last word always belongs to the mountain," a member of an Everest climbing party says early on in director Baltasar Kormákur's white-knuckle dramatization of a tragic 1996 expedition. Those words prove to be prophetic, as some of those who hear them never return from their quest to climb the world's highest and most dangerous mountain. Kormákur does a great job of quickly introducing viewers to the key members of two climbing expeditions, who eventually team up to tackle the treacherous journey to Everest's highest peak at 29,029 feet above sea level. One group is led by New Zealander Rob Hall (Jason Clarke), who helped popularize climbing Mount Everest in the 1990s with his company Adventure Consultants. The other pack is steered by his rival Scott Fischer of Mountain Madness (Jake Gyllenhaal), who accuses Hall of being a "hand-holder" who coddles his climbers. The laidback Fischer believes in helping his teammates as little as possible: If a climber needs a lot of assistance, it proves that he or she shouldn't be on the mountain at all. It's a foreshadowing of things to come, as their conflicting philosophies of leadership partly determine who survives and who doesn't. Among their clients are Beck Weathers (Josh Brolin), a cocksure Texan; Yasuko Namba (Naoko Mori), a Japanese woman who has already scaled six of the world's seven highest summits; Doug Hansen (John Hawkes), a humble Seattle mailman; Anatoli Boukreev (Ingvar E. Sigurdsson), a fearless Russian who refuses to use oxygen on the climb; and Jon Krakauer (Michael Kelly), a noted journalist whose eventual book, Into Thin Air, documents the horrific events that would transpire. The first half of the film follows the expeditions as they climb to base camps located at increasingly higher elevations, which allow them to acclimate to the altitude and its ever-thinner air. During these stops, relationships are formed and vulnerabilities exposed. We are also introduced to Hall's lead coordinator Helen Wilton (Emily Watson), who serves as a sort of den mother for the climbers. Hall warns his group that once they embark on the final trek to the top, they will enter the so-called "death zone." "Human bodies simply aren't built to function at the cruising altitude of a 747," Hall says. "Our bodies will be literally dying." That makes it imperative for the climbers to reach the summit quickly and begin their return by 2:00 pm. But weather conditions are notoriously unpredictable on Everest because, as one person points out, "the mountain makes its own weather." And on this fateful day, Everest whips up one of her most powerful snowstorms and sends it hurtling toward the climbers, some of whom are already suffering from oxygen deprivation, snow blindness, and fatigue. As the weary mountaineers struggle against the increasingly harsh elements, the question of who will live and who will die ratchets up the tension. And the fact that these events actually happened makes it all the more heartbreaking when we learn their fates. If Everest has a weakness, it's the sheer number of participants. Keeping track of who is where on the mountain when the storm hits is challenging at times, especially with so many people wearing goggles and oxygen masks. Fortunately, the cast are all first-rate, and each of them is able to carve out a distinctive presence and make us care about his or her character. Clarke, however, is the standout and the film's steady anchor. His authoritative yet welcoming presence puts everyone, including the audience, at ease, making us feel that we are in the best possible hands should an emergency arise. And his phone calls home to his pregnant wife (Keira Knightley) add considerable weight to the expedition's outcome. These individuals aren't just adventurers; they are spouses, parents, and sons and daughters. Everest was shot mostly on location in Nepal and Italy, with some studio work in London and Rome, but it all fits together seamlessly. Kormákur's harrowing film, which boasts a tight, intense screenplay by William Nicholson and Simon Beaufoy, is nothing less than a thrilling roller-coaster ride at the top of the world. It's worth every penny to see it in IMAX 3-D, which makes you feel as if you are right there, climbing the majestic mountain and caught up in the deadly storm. It's an adventure and a moviegoing experience you won't soon forget.