On Saturday, 26 April 2003, Aaron Ralston, a 27-year-old outdoorsman and adventurer, set off for a day's hike in the Utah canyons. Eight miles from his truck, he found himself in the middle of a deep and remote canyon. Then the unthinkable happened: a boulder shifted and snared his right arm against the canyon wall. He was trapped, facing dehydration, starvation, hallucinations and hypothermia as night-time temperatures plummeted. Five and a half days later, Aron Ralston finally came to the agonising conclusion that his only hope was to amputate his own arm and get himself to safety.