When you watch Sherpa you have an advantage over the documentary film-makers who shot it: they never knew what was coming.
Even those who have never heard about the April 2014 disaster, in which a 14 million-tonne block of ice crashed on to the Khumbu Icefall, killing 16 Sherpas, are given fair warning.
An opening sequence dramatises the moment with footage shot elsewhere, at another time, on a head-mounted GoPro whose bearer was in buried in snow: a title card announces impending doom.
That doom continues to impend for at least half of the film's running time and Antony Partos' score makes the most of it, lending depth to the Hitchockian idea that suspense is about waiting for something to happen.
The film was conceived, in the aftermath of the 2013 brawl between angry Sherpas and boorish climbers, as a portrait of the life of the people without whom Everest would not have been climbed once, never mind 7000-odd times.
But the icefall, known as a serac, changed all that.
There is no footage of it in the film, which is shot mostly at Everest Base Camp, but we are witness to its frantic scrabbling aftermath as rescue and recovery teams work and the death toll mounts; as Sherpas rage at political indifference and official corruption; and as the central figure, Russell Brice, the New Zealand-born doyen of expedition leaders, wrestles with the problem of whether to call off the climbs of his clients, some of whom are returning after the 2013 cancellation.
The film's other major character, a Sherpa named Phurba Tashi, is about to make what will be a record-breaking 22nd ascent and the film takes us into his home and his head as he seeks to provide for his family without losing his life in the process.
Less spectacular in its high-altitude sequences than more dramatic recent releases, Sherpa concerns itself much more with the human dimension of the Everest business, tangling with the complicated ethical and political questions inherent in the notion that the Third World is the First World's playground.
On one side is the idea, advanced by Phurba Tashi's wife, that climbing the mountain often is shameful to God; on another is a climber who can coolly complain that the Sherpas should do what "their owners" want.
The result is an Everest film for thinking people that is both thrilling and exhilarating, a real must-see.
96 mins Rating: M (offensive language) In English, Sherpa and Nepali with English subtitles
Thrilling and exhilarating.