***** (MA15+)

Director: Danny Boyle.

Cast: James Franco.

GREAT movies aren't necessarily fun to watch, yet they're still unmissable. 127 Hours is a case in point. It has to be seen to be believed, but you may not be rushing back for seconds.

You'll feel like you're clenching everything in your body as this movie builds towards its inevitable climax, but this is a masterful work that does exactly what it aims to do - put you in a canyon with a trapped man and deliver a blow-by-blow, close-range battle for survival.

Unless you've been living under a rock (sorry about that), this Oscar-nominated film tells the tale of Aron Ralston, a super-fit hiker/climber who was stuck in the wilderness for the eponymous amount of time before he had to do the unthinkable to free himself.

Boyle's direction gets the audience as close to the action as possible to capture for the audience some small amount of what Ralston had to go through - the frustration, the tedium, the agony, the small moments of exhilaration, the desperation, the claustrophobia, the practicalities, the ingenuity, the delirium and, ultimately, the power of the human spirit and the will to survive. Boyle achieves all this, which helps make this such a draining yet rewarding experience.

Then there's that scene, where Ralston does the unimaginable to get out from between a rock and a hard place. Unless you've worked in an operating theatre or happen to be a complete ghoul, you're not going to enjoy that scene, as integral as it is to the story. Boyle handles it superbly, giving the audience a weird catharsis and capturing the absurd reality of it all. But you may need some fresh air afterwards.

Reality is the name of the game here - Ralston himself has said 127 Hours is basically a dramatised documentary of his ordeal - and none of it would be possible without Franco's astounding performance. He really throws himself into the role, runs the gamut of emotions one can only imagine Ralston went through, and is utterly believable and engrossing. If Franco had pipped Colin Firth at the Oscars, you wouldn't have begrudged. This is a tough performance and Franco nails it.

The script is pretty amazing too. Despite being mostly set in the one place, it takes us out of the canyon through the use of fantasy and memory, inevitably taking us deeper into Ralston himself.

It's tough going, but nothing compared to what Ralston went through. And, after all, that's what this powerful film is all about.