The Rio Grande Valley sector of South Texas contains 17,000 square miles of borderland. Agents must be on constant alert to thwart a bold network of drug trafficking and human smuggling. In this episode, they put themselves in harm's way searching for armed smugglers fleeing a shoot-out with the Mexican military. Once at the riverbanks, they find a suspected smuggler who has been shot five times. Their mission quickly changes as they rush to save the man's life.