In the turbulent year of 1972, U.S. diplomat Mason Skiles resides in Beirut with his Lebanese wife, Nadia, and has recently taken in Karim (Idir Chender), a 13-year-old Palestinian boy who claims to be orphaned. During a party he hosts, Skiles is confronted by his colleague, CIA officer Cal Riley, who requests to interrogate Karim, whose brother is allegedly linked to the notorious Munich massacre. The gathering takes a dark turn when Karim's brother, Rami (Ben Affan), orchestrates an attack, leading to Karim's abduction and the tragic death of Nadia amidst the chaos.
Fast forward ten years, we find Skiles a broken man, marred by alcoholism and working as a labor arbitrator in New England. Struggling with his small business and haunted by the past, he is approached by an old client, Sully, who represents the U.S. government. Sully informs Skiles about an academic lecture in Lebanon, providing him with funds, a plane ticket, and a new passport. Initially hesitant, Skiles ultimately makes the journey back to Beirut, where he meets with State Department officials, including Gary Ruzak, Donald Gaines, and Frank Shalen, as well as CIA undercover agent Sandy Crowder. They reveal that Cal has recently been kidnapped, with the abductors specifically requesting Skiles for negotiations regarding his release.
In a tense encounter with the kidnappers, Skiles discovers that Karim has taken the lead in the situation, demanding the release of his brother in exchange for Riley despite warnings from the Americans that they lack Rami in custody. Skiles suspects that Israel may have Rami and, alongside Ruzak, seeks to uncover the brother’s whereabouts. Upon consulting the Israelis, they confirm Rami's absence, prompting Skiles to meet Alice ([Kate Fleetwood]), Riley’s wife, who blames him for the abduction, attributing it to the guilt he harbors for Nadia's death.
A clandestine meeting with Roni Niv (Alon Aboutboul) reveals Israel's ulterior motives, as he pressures Gary to leak news of Cal's death to justify an invasion of Lebanon with the intent to cleanse it of the PLO and Islamist factions. Skeptical of the plan, Gary wishes to keep hope alive for Cal’s survival.
As Skiles proceeds with his lecture, a devastating car bomb detonates outside, plunging the venue into chaos. In this turmoil, he meets Karim, who brings him to Riley, who discreetly informs Skiles of the PLO holding Rami and warns him about Gaines’s deceit. Karim demands a trade: Rami's release for Riley. Skiles learns that Gaines has been embezzling funds and concludes that he may be complicit in keeping Riley from being freed.
With urgency, Crowder pilfers $4 million from CIA funds to aid in the negotiations. Following a showdown with a senior PLO officer, Skiles orchestrates the dangerous exchange for Rami, but just as the deal appears to succeed, Rami attacks and is fatally shot by a hidden Mossad sniper, allowing the Americans a narrow escape.
Before leaving Beirut, Skiles discovers Gaines has abruptly retired, and Gary intends to seize this opportunity to fill the vacant roles, while promising to offer his expertise as a negotiator in the ongoing turmoil.
