Xia is one of the film's real-life inspirations-he lost his lower legs to frostbite on the mountain in 1975.

In February 2019, Xia was granted the Laureus Sporting Moment of the Year award in Monaco. He's the fourth Chinese individual recipient of the award, after basketball icon Yao Ming, Olympic champion hurdler Liu Xiang and tennis ace Li Na.

As well as the physical challenge of any attempt on the summit, there are also financial considerations. It costs about 500,000 yuan ($78,550) to climb Qomolangma. When he resolved to challenge the summit again in 2008, he sold his apartment in Beijing to cover the expenses.

On the three failed attempts in 2014, 2015 and 2016, it seemed nature was mocking him, with an avalanche, an earthquake and bad weather respectively scuppering his plans.

He's grateful for the unconditional support from his wife and son.

"My wife always understood my dream. All these years, I've devoted myself to my dream and had less time to deal with family affairs," Xia says.

His wife, Ma Yi, says in the documentary: "His thought process is a simple one, and he has a preoccupation with climbing. He's doing his best to fulfill an ideal. How could I prevent him from doing it?"

Two professional cameramen were in charge of recording his climb from Base Camp to the summit of Qomolangma. While the Nepalese cameraman had reached the world's highest peak several times, it's the first time for the Chinese videographer.