Directed by Kevin Macdonald. Starring Joe Simpson and Simon Yates. Rated PG.

For anyone who doesn't know crampons from croutons, the prospect of following a couple of gung ho Brits up a 6,300-metre South American peak--in real life or only in a movie--may seem too daunting a task. And when you learn that one of those climbers is destined to fall off the mountain into a 90-metre crevasse, well how much fun can that be?

As it happens, it can be pretty damn engaging, especially when the project is in the hands of documentarian Kevin Macdonald. His most notable previous effort was the Oscar-winning One Day in September, and he has directed or produced a number of documentary profiles of music and film personalities, as well as writing an exemplary biography of his grandfather, the great British filmmaker Emeric Pressburger.

It also helps that Simon Yates and Joe Simpson are such articulate and unsentimental recollectors of their tale of the climb, which happened in 1985. The mere fact that they are talking makes it obvious that they survived their tumultuous week at the top of the Siula Grande, in the Peruvian Andes. Simpson, in fact, wrote a book, also called Touching the Void, about their adventure, upon which the film is based. Macdonald jacks up the action while restaging the fateful climb, with actors Nicholas Aaron and Brendan Mackey playing Yates and Simpson, respectively, as their younger, more frostbitten selves.

The crux of the drama comes when Simpson gets injured and Yates has to make a fateful decision about what to do with the dead weight on his rope--a decision that led to harrowing torment for both men (not least of which was the hideous Boney M song that one gets stuck in his head). In a brief coda, we learn that Joe later stuck up for Simon when climbers turned against him, and eventually resumed mountain climbing. We're not told how the experience otherwise affected their lives and limbs. It's clear from their demeanour, however, that getting this close to the void made them very calm people. The movie, curiously enough, has the same effect on the audience.