Vertical Limit
In a mountain range in the Southwestern United States, veteran mountain climber Royce Garrett (Stuart Wilson) is traversing a cliff base with his son, Peter (Chris O'Donnell), and daughter, Annie (Robin Tunney). Amateurs above them lose their footing and endanger them all, eventually causing all three Garretts to hang precariously from a cable that cannot support their weight. Royce orders to Peter to cut the rope, sacrificing himself to save his children. Years later, Peter has retired from climbing and is a wildlife photographer. Annie has become a renowned mountain climber, but resents Peter for cutting the rope. When his assistant is injured, Peter shows up at base camp as Annie attempts to climb K2 in the Pakistan province of Gilgit-Baltistan, the world's second highest mountain, which is very dangerous to climb because of the tough conditions which await at the summit. Complicating matters further is the war between Pakistan and India, which has limited the expeditions support and resources. The expedition is funded by wealthy industrialist Elliot Vaughn (Bill Paxton) who is also going to climb, with the help of his friend Tom McLaren (Nicholas Lea). There is a huge party the night before the climbers begin the trek, which is briefly interrupted by an eccentric, Montgomery Wick (Scott Glenn), who warns that none have ever conquered K2, and none will. Vaughn is introduced to Peter, whom he asks to accompany them on the trip, but Peter instantly refuses.
As the expedition progresses, the base discovers a potentially devastating ice storm, which could endanger the expedition, but they cannot say with 100% certainty. Tom suggests that they return to base. Vaughn refuses, deciding to play the odds. The winds begin to wreak havoc. Annie, Vaughn, and Tom fall through a patch of ice and become trapped in a crevasse. Annie radios back to base using Morse code and Peter learns of Annie's plight. Due to the seriousness of the cave-in, the rescue party realizes that they may need explosives to blast a hole for a rescue. But the only explosive that they can get their hands on is old nitroglycerin in leaky canisters. Few climbers are willing to consider the trip. Peter manages to assemble a rescue mission with the base's best climbers including brothers Cyril and Malcolm (Steve Le Marquand and Ben Mendelsohn), Monique Aubertine (Izabella Scorupco), Kareem Nazir (Alexander Siddig) and Skip Taylor (Robert Taylor). However, the day before the rescue mission goes underway. Skip and Peter also go visit Montgomery, reported to be the world's best climber and foremost expert on K2. Wick reluctantly accepts after some serious convincing, and it is implied that there is bad blood between him and Vaughn. Skip is unable to go as Wick says he needs him on the ground directing the mission.
To maximize their survival odds, Wick decides to pair the strong climbers with the less experienced: Malcolm and Kareem (much to Malcolm's dismay), Monique and Cyril, and Peter and Wick. They each split up and take different entry points up the mountain with the hope that diversifying their explosives will increase the chances of at least one pair getting through if another has an accident with the unstable Nitro. Cyril constantly "flirts" with Monique (much to her dismay). Malcolm and Kareem have awkward conversations which Malcolm points to wanting to complete the mission faster. Monique and Cyril enter trouble when Cyril loses his balance and clings to the side of a cliff. After Monique secures her harness to him, the peak cracks and Monique also falls over the edge and the nitro falls from Cyril's backpack and creates a huge explosion that the other teams notice. Cyril is able to climb back up, however, while he cheers arrogantly lowering a harness for Monique, they both hear a rumbling noise. The explosion and crackling has in fact started an avalanche and is heading straight for Cyril. Cyril, unable to do anything watches and screams helplessly as the avalanches swamps him and subsequently throws him over the edge off the peak. Monique, still hanging onto the edge, manages to survive and get back onto the peak. She then radios in and informs base that Cyril has been killed, but orders them not to tell Malcolm yet.
Back at the station, nitroglycerin, used to clear rock formations etc., comes into contact with the sun and reacts and subsequently explodes, completely dumbfounding the crew. Base tell the groups to get their cases of nitroglycerin into the shade to avoid an explosion. Monique teams up with Peter and Wick and they successfully manage to avoid a calamity. Malcolm and Kareem just manage to get the nitroglycerin, but the can containing it leaks and it is exposed to the sun, killing both of them in the explosion. Monique, Wick, and Peter witness the explosion.
Meanwhile, underground, Annie begins to suffer from pulmonary edema, when water begins to form inside of the lungs, and she will die unless given medical attention. Tom is in a more severe state, with his leg and ribs broken. Vaughn is the only one unharmed and possesses the medical kit. Annie pleads with him to use dexamethasone (colloquially referred to in the movie as "Dex") to save Tom and herself, but Vaughn declines, unwilling to waste it on a "lost cause". More to the fact, Vaughn doesn't want to die and believes he and Annie have the best chance of survival.
During the trek the next day, Monique comes across a woman's body frozen in the ice that has been uncovered due to the second explosion. As she gets closer, Wick instantly recognizes the body and tells Monique not to touch her; it is his own wife, Mayama. After Wick collects a ring and an empty box that contained "dex" from his wife's body, he tells Peter that Elliot Vaughn is responsible for his wife's death. Vaughn's story from his first disastrous climb on K2 detailed that the "dex" was swept away, but Mayama always kept it on her person, meaning the empty box proves Vaughn used it for himself. Knowing that Vaughn's story is a fraud and that he contributed to the deaths of other climbers, Wick plans to kill him on the mountain and warns Peter that his sister ought to watch her supply very carefully. Peter and Monique begin to grow close and there is some mild flirtation as Peter helps her set bones on her broken finger; moreover, they talk about her relationship with Skip, for Peter to find out that it's mostly professional, and not romantic, as he had once thought. Meanwhile, in Annie's camp, as night comes Vaughn gives himself some dex, then kills Tom by sticking Tom with the syringe, full of air to save remaining dex for himself.
Annie radios Peter and tells him that she won't survive much longer and that he should save himself and turn back; he and Monique instead continue on their own early while Wick is sleeping. Wick wakes up to see them gone and Peter and Monique, having continued trekking up the mountain, soon find the place where Annie and Vaughn are imprisoned. They use the nitroglycerin to create a hole, enabling access to the survivors. As Peter attempts to rescue Annie and Vaughn, the harness begins to loosen but Wick arrives and secures it. Wick descends into the cave and harnesses Annie again, and though a weakened Vaughn thinks he is about to attack him, Wick attaches a harness to him as well, and along with Peter (with Monique towing the rope), they manage to pull Annie up with Wick and Vaughn still harnessed underneath.
As they pull Annie up a clump of snow is dislodged and Annie, Peter, Wick and Vaughn are all left hanging with just Monique supporting all their weight. With Vaughn below him, Wick understands they cannot be pulled up and calmly cuts the rope.
Recovering at base camp, Annie reconciles with Peter, who finally pays his respects at a memorial for those killed on K2, including the Wicks, Kareem, his cousin Ali, brothers Cyril and Malcom, guide Tom McLaren..