Mason Skiles (Jon Hamm) is one of the most important diplomats in the United States who left Lebanon in the 70s after a tragic incident. Ten years later, the CIA calls him back to a Beirut ravaged by war with a mission that only he can fulfill. Meanwhile, a CIA agent (Rosamund Pike) who works undercover at the US embassy is tasked with keeping Skiles alive and ensuring the mission is a success. Without knowing who is on his side and with lives at stake, Skiles must overcome all obstacles to expose the truth.