Arnulfo Rubio, a young Mexican, works with a gringo barely older than himself to smuggle weapons from Arizona to Mexico for a drug cartel. We follow him buying weapons, crossing borders and during his almost familial encounters with middle-men and clients. What Arnulfo does not know is that for some time he has been under surveillance by agent Hank Harris. Harris is a member of US law enforcement organisation ATF, an agency notorious for its dubious methods when it comes to combating Mexican drug cartels. One day Harris makes a fateful mistake; Arnulfo panics and decides to take the agent hostage and hand him over to his clients in Mexico. During their long road trip from Arizona to Culiacan the two very different men begin – albeit awkwardly – to warm to each other. But no sooner do they arrive at their destination than events come thick and fast. An inexorable spiral of violence is unleashed and their fates soon become inextricably intertwined. An utterly hopeless situation for Arnulfo, that leads to a deeply ambivalent, emotional ending …