Chris Sharma, hailed as the world’s best rock climber, takes on his biggest challenge yet – the unclimbed 90-metre limestone cave atop Clark Mountain in the western U.S. To reach the top, Chris dangles from one finger, jumps between miniscule holds and suffers 30-metre freefalls onto his rope in his attempt to piece the climb together. He spends days just trying to get down two moves, using almost maniacal devotion to master complicated manoeuvres required for the climb. After months of effort, Sharma is still unable to complete the climb without falling. The oppressive summer heat moves in and he must retreat to Spain to continue training. Returning to Clark Mountain, Chris continues working towards a goal that seems a little beyond his limit. Finally, after months of effort, Chris manages a no-falls ascent of the entire 76-metre cave, achieving the first ascent of Clark Mountain in arguably the most difficult rock climb ever ascended.