Ever put a lot of time and money into planning something, only to have it all go horribly wrong?
Then you might have an understanding of how the makers of Sherpa felt when their tale of alpine conquest was derailed by the worst mountaineering disaster in Himalayan history.
"The story we thought we were going to tell, that we planned to tell, was the story of Phurba Tashi, who's the world record-holding Sherpa for the number of ascents of Everest that he's made," explains Sherpa producer Bridget Ikin.
Tashi held the world record already, having conquered Mt Everest 21 times before -- a fact not lost on his long-suffering family, who feared God would punish him for disrespecting the peak Sherpas call Chomolungma.
"We didn't know exactly how the story would unfold, but we would show his climb and the rest of the Sherpa team, and whatever came out of it would be the story," says Ikin.
This was the story Universal Pictures signed on for, and the one director Jennifer Peedom -- herself an avid climber -- wanted to tell after having developed a close relationship with the Sherpas.
Peedom and her crew arrived in April 2014, a year after tensions had flared between the poor Sherpas and their wealthy Western clients. It wasn't long before the unimaginable happened -- a 14,000-tonne block of ice broke free, killing 16 Sherpas.
Needless to say, Universal bosses didn't get their Everest ascent.
"We came back and said, 'Sorry guys -- no summit story this year,'" says Ikin. "The first thing they said was, 'Can you go back next year?' I said, 'No. We're not going back.' … I just had to trust that we would find a good story."
With only a single member of the crew able to speak Nepali, and few of the Sherpa fluent in English, the following week's events were somewhat of a mystery to many on the mountain.
"We had quite a specific story that we planned to get and we didn't come back with it, so we had to find what the new story was," says Ikin. "We weren't even sure if we had a film, because everything was untranslated. It took us about three months to get all the translations done and sort of recognise that there was gold in it."
What they had was not just the tale of a single man's relationship to Chomolungma, but that of an entire people.
"We were kind of given a front-row seat into this extraordinary unfolding of events that was completely spontaneous and surprising, when the Sherpas' grief turned to anger and resentment."
The tragedy sparked the world's highest-altitude workers' uprising, with the Sherpas very reasonably demanding better pay and conditions. But with so many of them -- and their families -- dependant on the climbing industry for an income, it wasn't long before cracks appeared in the makeshift union.
"It's lucrative and it's work on the one hand, but the price they pay can be so extreme," says Ikin. "There's such a narrative of sadness and grief in almost every Sherpa family because they have lost members of their family, sometimes over generations."
Every good story needs a villain, which Sherpa provides in the form of New Zealander Russell Brice. As the manager of the company which runs the ill-fated expedition, it's left to him to emphasise the financial realities of calling off the year's climbing season, which many of the Sherpas want to do.
In the film, Brice claims most of the Sherpas realise they have little choice but to keep climbing, but a small group of four or five "terrorists" -- as one disgruntled client calls them -- are threatening to break their legs if they don't join the strike.
Many of the Sherpas, however, say they've heard no such threats -- so was Brice lying? Ikin doesn't know, but says he was under a lot of pressure, with many of his customers having been on a previously cancelled expedition.
Also, Mt Everest -- like many other workplaces -- is a hotbed of gossip, much of it in another language or passed on in broken English, quickly losing its meaning.
"Don't forget that we have the hindsight of the subtitles in the film, and in an environment where everyone is speaking a language that you don't understand -- and we were filming in a language we don't understand either," explains Ikin.
"It looks now like everyone knew what was going on. In fact, it was just an extremely chaotic week -- everything was filmed in a week -- with no one really knowing, all these rumours going around, no one quite knowing who was saying what.
"I don't want to sort of defend what Russell was saying, but that's the context for it. It was a confusing week."
Further disaster for the Sherpa community was to come -- 7000 of them were killed in the following year's earthquake, and the climbing season was again cancelled.
Despite the consecutive tragedies, Ikin doesn't think the West's obsession with conquering Mt Everest will abate anytime soon.
"Statistics show that after every year where there's been a major calamity, the next year -- oddly -- there are more people that want to climb.
"But as our main cinematographer said, there are many more beautiful unexplored mountains out there, and if anything I would hope that the story that we tell might encourage people to just explore more generally. Even in Nepal, there are hundreds of exquisite mountains, some of which don't even have a name."
Sherpa opens in New Zealand cinemas on April 7.