After canceling their flight from Boise Airport due to bad weather, neurosurgeon Dr. Ben Bass (Idris Elba) and photojournalist Alex Martin (Kate Winslet) contact Walter (Beau Bridges), a local private pilot, to be able to reach Alex’s wedding next night, and Ben has scheduled an operation in Baltimore, Maryland. Shortly after landing, Walter suffers a heart attack and the plane collapses on top of a mountain. Ben and Alex are just a few wounds, but Walter dies.
Ben buries Walter and cares for Alex’s wounds, realizing that they have to find civilization if they want to survive. Alex asks Ben to leave it behind because he has more chances of survival, but Ben refuses and instead climbs a peak to see if there is any trace of civilization nearby. Isolate several days with little supplies, Ben and Alex support each other.
Alex gets skeptical about someone coming to save them, but Ben insists this will happen. After a fierce fight, the two put themselves to sleep, and Alex claims she will leave from there. As she lights up, she charges to leave the wreckage of the plane and descend from the mountain. Ben, however, follows her and catches her, and then the two are sheltering in a cave. Alex uses his camera to try to locate any man-made structure and finds some reflective material, and then agrees to go to that place.