The auspicious and appealingly confident feature debut from writer-director Cary Joji Fukunaga focuses on two Central American teenagers—a headstrong Honduran girl (Paulina Gaitan) and a gloomy Mexican gang member (Edgar Flores)—whose paths fatefully cross atop a freight train heading north toward the United States. Borrowing from Westerns, noir thrillers and mob movies whose habit is to wonder aloud whether the promised land’s promises ever really can come true, Sin Nombre also points out that just getting there at all is hard enough to begin with. Fukunaga has a fine sense of proportions, combining professional and nonpro actors to good effect, creating equal space in his narrative for the desperate and the driven, and achieving an atmospheric balance between sensitivity and brutality. Likewise, Adriano Goldman’s excellent cinematography seems equally attentive to details both ugly and beautiful. It doesn’t pretend to be a documentary, but it does feel authentic.