There is a gray area on the border between the United States and Mexico, where drug dealers and killers have a paradise. They trade and fight here, completely disregarding the law. Kate (Emily Blunt) is an FBI agent with the ideal of justice to punish evil. She came here and joined the federal government's special forces and became Matt's (Josh Brolin) subordinate. Alejandro (Benicio Del Toro) is a former agent who once worked undercover beside the drug lord. Matt found him and hoped that he could become a strategic advisor to the action team with his experience. However, Alejandro, who had experienced hell, did not play by the rules at all. His actions often stimulated Kate's fragile and sensitive nerves. As the investigation deepened, the breath of death enveloped everyone in the action group. Kate's three views began to waver after brushing shoulders with death again and again.