Dir: Walter Salles. US-Argentina-Chile-Peru. 2003. 128mins

A stirringly compassionate road movie that charts Ernesto "Che" Guevara's political awakening over the course of one seminal year, Motorcycle Diaries proved the early revelation at this year's Sundance Film Festival where Focus Features swept it up within hours of its world premiere screening on Saturday night. But this is not about Che, the poster boy of student radicals and guerilla-fatigue fashionistas the world over, but the personal odyssey of a lusty young Guevara as he and his companion traverse the South American continent in what would prove a turning point year in their lives.

Rather than try to deify or debunk that myth, Walter Salles and his inspired team of collaborators delight in simply documenting the telling human and vivid geographical details that would eventually inform the future revolutionary leader. The affecting result illuminates the legend more than any conventional screen biography could hope to, while also stirring the idealist within us all.

The amount paid at Sundance for Motorcycle Diaries, some $4m for United States rights, is certainly a breath-taking sum for a Spanish-language film. But given the warm enthusiasm with which this subtitled work was embraced by audiences at a festival more accustomed to US indies, there seems no reason why Walter Salles cannot stretch beyond his own Central Station in terms of box office appeal.

The success of Y Tu Mama Tambien, another politically-charged buddy trip headlining the charismatic superstar-in-waiting Gael Garcia Bernal, would seem the obvious initial benchmark. And with Terrence Malick now working on his own interpretation of the martyred Guevara, Motorcycle Diaries also stands to benefit down the DVD road from any outbreak in Che-mania.

It was in January 1952 that the 23-year-old Ernesto Guevara de la Serna (Bernal) set out from Buenos Aires with his family friend Alberto Grenado (Serna) on a clapped-out old Norton motorbike. The products of well-to-do middle-class Argentine upbringings, both wanted to fulfil a restless urge to see the rest of South America before settling down to their medical careers. The aim: to reach Venezuela, by way of the Andes, the Chilean and the Peruvian Amazon, by the time Alberto celebrated his 30th birthday.

At the onset, Guevara and his carefree comrade-in-adventure resembled far more Latin versions of Jack Kerouac than they did rebellious insurgents on a mission to tackle the social injustices of the oppressed. Sex and general carousing occupied far more of their rollicking minds than politics. But with every mechanical disaster and subsequent need for food and shelter came ever more painful collisions with the South American underbelly. Their adventures bring them face-to-face with Indian farmers thrown off their cultivated lands, with ugly urban sprawls that have replaced their continent's magnificent Incan heritage and with communist sympathisers banished to a life in the mines - assuming they can even get the miserable work.

Eventually, they end up helping out in the largest leper colony in South America, right in the heart of the Amazon, by which time Ernesto and Alberto have seen their consciousnesses raised and their destinies altered. It is a testament to Jose Rivera's screenplay that such a historically significant voyage of self- discovery should not be seen to hinge on any revelatory moment of truth, the way that aggrandising bio-pics so often do.

With the help of his two immensely likeable and gifted actors, Salles shows their eyes gradually opening to the harsh realities that surround them. What we witness is not Che-in-the-making, but rather the exuberant adventures of Ernesto and Alberto, believably flesh-and-blood, whose constant sparring provides the film with its emotional heartbeat.

The director's documentary background also helps immeasurably in anchoring a narrative that could too easily have mythologised, or been too worshipful in its treatment of both poor and these two young men who dedicate their lives to their cause. If anything, it is the faces of the socially oppressed, captured in the as black-and-white portraits, that become glorified rather than the iconic face made famous on a myriad of T-shirts in the years since Che was murdered in Bolivia.

Production companies: Film Four, South Fork Pictures, Tu Vas Voir Productions
US distribution: Focus Features
International sales: Pathe International
Executive producers: Robert Redford, Paul Webster, Rebecca Yeldham
Producers: Michael Nozik, Edgard Tenembaum, Karen Tenkhoff
Co-producers: Daniel Burman, Diego Dubcovsky
Screenplay: Jose Rivera
Cinematography: Eric Gautier
Editor: Daniel Rezende
Music: Gustavo Santaolalla
Production design: Carlos Conti
Costume design: Beatriz Di Benedetto, Marisa Urruti
Artistic supervisor: Gianni Mina
Cast: Gael Garcia Bernal, Rodrigo de la Serna, Mia Maestro, Mercedes Moran, Jorge Chiarella, Gabriela Aguilera