As the directorial debut of Carl Fukunaga, a 32-year-old graduate of New York University's Film School, Sin Nombre dabbles in the ostensibly paradoxical genre of morality tales lifted from the criminal demimonde. It appears to be an aesthetic shared by a number of recent NYU film-school grads. Joshua Marston turned drug smuggling into an ode to survival in 2004's Maria Full of Grace. In The Woodsman, also from '04, writer-director Nicole Cassell did the seemingly unbelievable with a sympathetic portrait of a convicted pedophile seeking redemption of sorts.

Sin Nombre isn't quite as defiantly edgy as those efforts, but Fukunaga is a gifted storyteller whose lyricism and visual style elevate the material above what easily could have been overwrought melodrama. Hard-edged and absorbing, the film heralds the arrival of a promising new director.

The Spanish-language movie interweaves the stories of two young people who eventually cross paths. In Chiapas, Mexico, Willy (Edgar Flores) seems like an atypical gang member. He is a quiet, sensitive soul in love with his girlfriend (Karla Cecilia Alvarado), but the teen - who goes by the nickname Casper - is part of the brutal Mara Salvatrucha gang. His allegiance to them is sorely tested when one of the top-dog gangsters, the heavily tattooed Lil' Mago (Tenoch Huerta Mejía), accidentally kills Casper's girlfriend while trying to rape her.

Fear keeps Casper from lashing back, but things reach a breaking point for him shortly afterward, when he joins Lil' Mango and a 12-year-old gangbanger, Smiley (Kristyan Ferrer), in robbing immigrants who are hitching a train ride from Central America to the U.S.-Mexico border. Lil' Mango accosts a 14-year-old Honduran girl named Sayra (Paulina Gaitan), and Casper can no longer stay silent.

Casper saves the girl, but makes himself a target in the process. He remains on the train, ostracized by the other passengers hoping to avoid trouble for an already-treacherous trip. His sole ally is Sayra, who befriends the young man much to the frustration of her father and uncle.

The winner of direction and cinematography honors at this year's Sundance Film Festival, Sin Nombre is a curious but often-dazzling mix of grittiness and visual splendor. It does not shy away from the viciousness of Casper's thug life. In the opening minutes, the Mara Salvatrucha initiate young Smiley into the gang by pummeling him into a bloody mess. The film suffers no shortage of misery.

Still, the poverty and despair of its characters' lives is alleviated, and almost romanticized, by the movie's fluid camerawork and picturesque views of the Mexican countryside. Some scenes - the ghostly images of railway lines at night, an afternoon rain shower - are evocative and powerful. While the visual flair can sometimes be too glossy for its own good, there is no denying that it makes for arresting filmmaking.

To his credit, Fukunaga skirts sentimental territory without surrendering to sentimentality. His leads certainly help, especially Flores, a non-professional actor who shows real depth as Casper. He and Sayra make selfless but dangerous choices, decisions in which the right thing is miles away from self-preservation. In the end, Sin Nombre is about the fight to hang on to one's humanity in an environment where it is being all but snuffed out.

In anamorphic widescreen and preserving the theatrical 2.35:1 aspect ratio, Sin Nombre boasts a stunning picture. Details and colors are strong and vibrant. With the exception of minor edge enhancement here and there, this is an outstanding picture quality.

The Spanish 5.1 track is sharp and crisp, with modest but effective use of surround sound.

Optional subtitles are in French and English for the hearing impaired. One minor complaint: the font size of the English subtitles is smaller than the norm.

Fukunaga and producer Amy Kaufman join for an insightful and informative commentary that helps shed light on the challenge of the film shoot. Fourteen deleted scenes, which cannot be viewed separately and have an aggregate running time of 10 minutes and three seconds, are dispensable.

A number of the scenes require manually switching on the subtitles function.

Dark, gritty and surprisingly beautiful, Sin Nombre is a testament to the directorial skills of Carl Fukunaga. While nominally about an immigrant's experience en route to the U.S., the movie resonates more powerfully as a morality tale. Its case of largely non-professional actors is dead-on, especially its young leads.