WHAT did you do in your gap year? In 1952, two young Argentinians, Ernesto Guevara and Alberto Granado, set out on a road trip on their battered motorbike to discover South America.

They crash bikes, chase girls and work in a leper colony, the stuff of every student summer holiday.

Then they go their separate ways, one to change the world, the other to appear at the end of Waler Salles's film, having seen the actor playing him (Rodrigo De la Serna) steal the acting honours from the hottest new South American talent, Gael Garcia Bernal.

Ernesto Guevara was to grow into Che Guevara, perennial poster and T-shirt icon, and The Motorcycle Diaries sows the seeds of the revolutionary progression of an already serious young man, with Guevara's diaries of the title providing the source material.

As he sets out with close friend Alberto, Ernesto (Bernal) is 23-year-old medical student specialising in the study of leprosy; Alberto (De la Serna), six years older at 29, is a biochemist, more experienced in the ways of the world and women.

Salles observes - as Ernesto the journal writer observed - the Latin American world around them, with the detail of a documentary maker and the romantic heart of a film maker with an impressively light touch. Amid the ever-changing scenery, the two men undergo their journeys of self-discovery, confronted by inequality and deprivation.

Guevara's political awakening is not laid on too thick; instead it forms part of the web of Jose Rivera's script, which combines humour with intelligence, reflection with foresight and integrity with playfulness.

Bernal continues to build an impressive CV of young roles, proving himself more than a pretty face, although the more exciting discovery is De la Serna. Hollywood will be watching.

Updated: 16:02 Thursday, September 02, 2004