The next time you hear some twit blathering on about the immigration debate and how "easy" it is to breach America's southern border, kindly tell them to shove it and point them toward the riveting and revelatory Sin Nombre. While it may indeed be a Hollywood invention, you'd hate to imagine a reality more harrowing, cruel and strangely beautiful than the one depicted here.

The film tracks the intersecting paths of two young South American teens doing whatever it takes to find some kind of better future, though they approach that destiny in radically different ways. Sayra (Gaitan) is a sweet-natured Venezuelan girl, northward bound on a freight train with her father and uncle, and Willy (Flores), is a clever Latino kid trying hard to make his bones with a huge, lethal gang. That gang exists in a truly hellish, violent underworld of rusted hideouts and is locked in perpetual war with crosstown rivals, and hungry for new recruits, all too easy to come by on the desolate barrio streets.

Fearsome, face-tattooed leader Lil Mago (Tenoch Huerta Mejia) enlists Willy and his even younger protégé to hop the train and rob the hapless travelers. Sayra and Willy soon form a bond, and a sudden moment of violence turns the pair into fugitives, making the race to "El Norte" even more desperate.

First-time director Cary Fukunaga shows extraordinary grace and control, creating a throat-gripping immediacy that only occasionally cracks under the strain of plot coincidences. Along with cinematographer Adriano Goldman, Fukunaga creates a lush, sunset-hued world that captures every bit of dirt and grime, but also fleeting glimpses of fertile farms and lovely mountainsides in the distance. Sin Nombre is a fitting companion piece to other recent gritty South American instant classics like Maria Full of Grace and City of God, films that took breathtaking, unflinching looks at squalor and desolation, but still found some grace and reasons to hope for something more. You can't ask for much more from the movies.

Corey Hall writes about film for Metro Times. Send comments to letters@metrotimes.com.