Nils Johnson and his wife Elizabeth leave their Denver home for an excursion to the mountains, where Nils hopes to rekindle the sparks of their love for each other after he had an affair. In their younger years, they had been avid mountain climbers, and Nils hoped that being outdoors would remind Elizabeth of those better times. On the trip, however, Nils gets distracted by two boys who are attempting to climb the mountain, though Nils can tell that they are inexperienced. After he and his wife make love in the morning, he sees one of the boys fall. The other holds him suspended in the air, but cannot do much else. Nils and his wife head for the mountain. Though they weren't planning on a major climb, they have some equipment and plenty of experience. After several hours of climbing, they see another camper begin to climb as well. This man climbs alone and is more skillful than anyone they've ever seen. He reaches the Johnsons before they reach the stranded boys and introduces himself as Calloway. Together they formulate a rescue plan. When Nils and Calloway reach the two boys, they see that the one who had fallen died during the fall, and the other boy is in shock. They decide to cut the body down and let it fall to the ground since it would be impossible to carry off the mountain. Then the remaining four of them link up and start to climb the rest of the way up the mountain, which is faster than climbing all the way down. After a dangerous climb in the dark lit only by flashes of lightning, they find a ledge to camp out for the night. In the morning, they split into pairs, the surviving boy requesting to climb with Nils, and continue up the mountain. Elizabeth and Calloway climb ahead of Nils and the boy, so fast that Nils loses sight of them. The climb is difficult and it is made harder by his partner's inexperience. After slipping and nearly losing his life, Nils manages to hold on, and they eventually make it to the summit. Nils feels betrayed by his wife for abandoning them, and he realizes that that was how she must have felt after he had cheated on her. They reconcile and then turn their attention to the surviving boy and his dead stepbrother.