With just a handful of cinematography credits and a pair of short films to his name, filmmaker Cary Joji Fukunaga makes his impressive feature directorial debut with Sin Nombre, an emotionally involving thriller following a Honduran teen and a marked gangster on their flight toward the Mexico/U.S. border. Harsh yet hauntingly tender, the film succeeds as a well-crafted thriller, an unflinching look at the difficulties of escaping gang life, and a harrowing study of the desperate lengths that immigrants will go to in hopes of building a better life. Teenage Sayra (Paulina Gaitan) hasn't seen her father since she was just a young girl. She lives in poverty in Honduras, so when dad returns announcing that he plans to rendezvous with his new family in New Jersey, she seizes the opportunity to head north and start a new life. Meanwhile, in Mexico, Tapachula teen Willy (aka Casper, played by Edgar Flores) has gotten involved with the notorious Mara Salvatrucha street gang. Yet, despite delivering a new recruit to the Maras in the form of desperate 12-year-old Smiley (Kristyan Ferrer), Willy seems more interested in spending time with his secret girlfriend than executing rival gangsters for feared Mara leader Lil' Mago (Tenoch Huerta Mejía), whose heavily tattooed face lends him the shocking appearance of a hybrid neo-Nazi fanatic/Maori warrior. When Lil' Mago catches Casper and Smiley in a lie, he insists that they join him on a mission to rob a train full of desperate immigrants headed for the Mexico/U.S. border. As violence erupts and tensions flare atop the moving train, Sayra's and Casper's paths cross. In the chaos, Lil' Mago is killed and Smiley is kicked off the train. Now, in order to prove his allegiance to the Maras, young Smiley and a heavily armed gang of Maras make it their mission to catch the train and exact bloody vengeance against Casper. The first thing audiences will likely notice about Sin Nombre is Adriano Goldman's gorgeous cinematography; striking a unique balance between gritty and purposefully hyper-saturated, Goldman gives the film a distinctly seductive visual texture right from the cleverly deceptive first frame. And by alternating between Sayra's grueling hike north and Casper's falling-out with the Maras early on, Fukunaga's screenplay seamlessly sketches out rough backgrounds for both characters while efficiently leading us toward their ultimate destination -- a train bound for the Mexico/U.S. border. From Casper's initial rendezvous with his "downtown" girlfriend, it's obvious that he has his doubts about gang life. He isn't particularly aggressive, though when backed into a corner by Lil' Mago and forced to help Smiley with his initiation killing, it's obvious he knows that disobeying orders could have dire consequences. Flores conveys Casper's reluctant complacency in a way that tells us a lot about his character as well; though Casper (or Willy, as he comes to be known by Sayra) never expresses it outright, one gets the distinct impression that circumstance -- not an express desire to violently defend his home turf -- was the primary factor in his becoming a Mara. Likewise, Sayra's naïve trust in Willy tells the viewer that, while she may be a decent judge of character, she isn't quite attuned to the dangers that await her outside of Honduras. Gaitan instills the character with a certain sense of vulnerability that's somewhat offset by her youthful bravery, so when she leaves her father behind in order to follow Willy, her actions are entirely believable. As the villain who sets the plot into action, Huerta couldn't be more terrifying. Lil' Mago is all inky smiles as he calmly ignores pleas for mercy from a rival gangster while informing him that he will soon be -- quite literally -- dog food. Considering that the visually repugnant Lil' Mago is such a compelling character, it's a shame that he's dispatched relatively early in the film, though Fukunaga ups the ante by filling that void with a villain that is infinitely more disturbing due to his innocent appearance. It's a fascinating contrast, and one that helps to make a somewhat predictable ending a bit more satisfying. So, while Sin Nombre wisely never tries to trick us into seeing it as anything more than a thriller, it's obvious from the characters and the nuances within the story that writer/director Fukunaga has bigger issues on his mind, and it will certainly be interesting to see where he decides to take his career as he continues to mature and develop as a filmmaker.