Aron Ralston's story of having to hack his own arm off after he became trapped in the Utah Canyonlands was presumably very well known, even before the great Danny Boyle got hold of the story to make into a film. The plot doesn't really need that much explaining, but I must stress that my view is based on the film, as I haven't read Aron's book "Between a Rock and a Hard Place" yet.
Essentially, Aron went away for a weekend to go mountain biking, hiking and climbing in Canyonlands in Utah. After having spent an afternoon with two girls he met while hiking they head off their way and Aron continues on his way to a big "Drop-off", where a smaller canyon opens out into a much larger canyon. However, as he quickly descends into a narrow gorge he slips, dislodges a large rock which, when he lands on the canyon floor, traps his right hand against the canyon wall. Aron is stuck, completely isolated, low on food and water and unable to free his hand. So after 5 soul-searching days (127 hours in fact) of trying one way or another to shift the rock, he finally amputates his own arm so that he can get home.
The majority of the film is just Aron (James Franco), in a canyon, experiencing various emotions from disbelief, through anger, frustration, despair, desperation, and finally determination. Wow! James Franco is fantastic. There isn't a minute when you don't believe that he is there experiencing all of this. I thought the film-making was also phenomenal to make this story so gripping (a man stuck in a hole for 5 days!), and I don't think there was a single camera angle that Danny Boyle didn't use!
The story was well spaced out with flashbacks of family, past girlfriend, and how he feels he has let people down; perhaps that's too strong but certainly the impression is that he feels he has not given those close to him the love that he can give. Finally it is the thought of his family, and the desire to start his own family that cements in his head that he must amputate himself to get out of there. I think I have heard of some people feeling very sick and grossed-out by the amputation scene. Maybe I've seen too much horror, but I thought is was subtly done, far worse for me was before he fell into the canyon knowing that something awful was going to happen. Much like Touching the Void.
The other very similar part to Touching the Void was Aron getting the music to Scooby Doo in his head! This is because the girls he had met on the first day had mentioned that they were throwing a party that night and there would be a huge inflatable Scooby Doo there. So part of the delirium Aron experience was having the Scooby Doo music going round and round his head. Very much like Joe Simpson thinking he was going to die to "Brown Girl in the Ring" by Boney M!
Anyway, I thought the film was great, brilliantly made, a great example of how filming one man in isolation can still be gripping. I've heard great things about Buried as well, and if it's half as good as this is, it must be a good film.