In his first feature film, Cary Fukunaga delivers a beautiful and powerful depiction of the lives of Central Americans crossing through Mexico to the United States border. Sin Nombre (Without Name) unfolds mostly on top of trains, and it’s enriched by years of painstaking research, including Fukunaga’s own rides atop Mexican boxcars. This electrifying film will break viewers’ hearts and raise their social consciousness.

Willy (Edgar M. Flores), aka El Casper, is a teenage member of a Mara Salvatrucha gang in the southern Mexi can border down of Tapachula. He’s been charged with mentoring Benito (Kristian Ferrer), aka El Smiley, through his initiation—which includes a violent beating supervised by Lil Mago (Tenoch Huerta Mejía). Smiley goes on to accompany Casper on patrols of the neighborhood around the train yard.

The gangsters’ story is woven together with that of another group shaped by grinding poverty: Central American migrants who risk life and limb to ride the trains through Mexico. Horacio (Gerardo Taracena) has been deported from the United States back to Hon duras. He returns to Teguci galpa, where he beholds his now-teenage daughter Sayra (Paulina Gaitan) for the first time in years. Horacio invites Sayra, along with his brother, to return with him to the States, where he now has another family. With all of their possessions in a few rucksacks, the three set out on foot across Guatemala to southern Mexico, where they board a northbound train.

The characters converge at the Tapachula train station, where Lil Mago—accompanied by Casper and Smiley—has chosen to rob the same train that Sayra and her family have boarded. But by now, Casper’s loyalty to the Mara has been pushed to its limits. A violent scene culminates in Casper staying on the train and falling in love with Sayra; thus a member of the dreaded Mara Salvatrucha becomes the unlikely protector of a Honduran migrant. From there Sin Nombre alternates between romance and suspense thriller, as Casper and Sayra travel on top of the train, with a transnational band of Mara gangsters in hot pursuit.

Sin Nombre tells the story of politically voiceless migrants from Central America and Mexico, but it accomplishes this without overt political commentary. Instead, Fukunaga weaves the stuff of social documentary into the fabric of an adventure-romance film: in close-ups of scars on gangsters’ bodies, in long shots of filth in train yards, in choice background scenes of Mexican locals throwing food onto the speeding trains—or throwing rocks at them.

Fukunaga and cinematographer Adriano Goldman also display supreme talent in casting landscapes as characters in their own right. The polychromatic aesthetics and tropical lushness of Mexico and Central America are incorporated into every one of the film’s scenes, which were often shot through a red filter lens.

This visual beauty balances the bleak story and comes to embody the migrants’ hope against the odds. The nighttime scenes, particularly those shot at the Tapachula train yard, provide contrast by drawing on the shadow-and-light techniques of film noir to evoke the sinister milieu in which the lives of the characters unfold.

The moral ambiguity of Sin Nombre’s characters parallels this alternation between day and night, hope and despair. There is nothing particularly novel in portraying illegal migration by some of the world’s poorest people as a morally defensible act. But Fukunaga’s complex depiction of the Mara Salvatrucha—not only Casper but the other gangsters as well—is remarkable. Real-life Central Amer ican migrants cross Mexico in well-founded dread of encountering the Mara gangs. But alongside its scenes of blood and gore, Sin Nombre highlights the Maras’ humanity.

There are scenes within the gang’s Tapachula headquarters showing the gangsters as a rather domestic lot: cooking, listening to music and adorning each other with tattoos. Lil Mago, an otherwise terrifying character, is seen as a loving father cradling his newborn baby. And then there’s Smiley, who ascends as a gangster primarily to find a community of support and love. Against the forces of poverty and political neglect, both migrants and gangsters wage heroic struggles for belonging and dignity.

Unlike many films on Latin American migration, Sin Nombre gives little attention to trials and triumphs on the U.S. side of the border. Instead, it forces viewers to gaze upon the perils of making it through Mexico with body and soul intact. Fukunaga’s outstanding film is an initiation in it own right. By turns both wrenching and tender, it draws viewers into a landscape that sometimes seems ruled by the devil himself.