The first novel in the Gray Man series opens in western Iraq, where Court Gentry, an American private assassin known as the Gray Man, flees across the desert after killing Dr. Isaac Abubaker, the Nigerian minister of energy, in eastern Syria. Racing toward his helicopter extraction into Turkey, Court witnesses a U.S. Army Chinook crash into the town of al Ba'aj. Al Qaeda fighters converge on the wreckage, executing American soldiers while a camera crew films. Court opens fire with a sniper rifle, destroying his exfiltration timeline. He later ambushes a pickup truck carrying two captured soldiers, rescues Private Ricky Bayliss, and sends the wounded guardsman toward a U.S. forward operating base before vanishing.
In London, Sir Donald Fitzroy, a 68-year-old former MI-5 officer who secretly manages private assassins through his firm Cheltenham Security Services, receives a threatening visitor. Lloyd, a young American attorney for LaurentGroup, a massive French multinational conglomerate, reveals he knows Court's identity, his CIA background, and Fitzroy's role as his handler. Lloyd explains that Nigerian President Julius Abubaker will not sign a multibillion-dollar natural gas contract with LaurentGroup unless Court's severed head is delivered before the president leaves office. The assassination of Abubaker's brother Isaac has made the demand personal. Lloyd, a former CIA officer, copied Court's complete personnel file upon leaving the agency and provided it to Abubaker. He threatens Fitzroy's family with surveillance photos proving they can be reached at any time.
Fitzroy refuses but is overwhelmed by fear for his family. He sends his son Phillip, daughter-in-law Elise, and eight-year-old twin granddaughters Claire and Kate to a Normandy cottage, but Lloyd's operatives discover them there. Coerced by this leverage, Fitzroy orders a five-man extraction team to kill Court mid-flight out of Iraq. Court detects the threat, and a gunfight erupts inside the cargo plane. He kills four operators, grabs the parachute harness of the fifth, and rides the reserve chute to the ground. The fifth man dies on impact. After treating a bullet wound to his thigh, Court walks toward Turkey.
When Court calls Fitzroy, the old handler lies, blaming the attack on Nigerian mercenaries. Lloyd listens on speakerphone, then orders the Fitzroy family seized and imprisoned at Château Laurent, a LaurentGroup estate in Normandy. Court, trusting Fitzroy, pledges to rescue the family. Meanwhile, Kurt Riegel, LaurentGroup's vice president of security operations and a former German military officer, organizes a massive manhunt, recruiting government kill squads from 12 countries. Each team receives one million dollars, with 20 million reserved for whichever team kills Court. Nearly one hundred surveillance operatives track his movements across Europe.
Court flies to Prague under a forged passport, but a LaurentGroup agent identifies him. He kills three Albanian operatives in a metro tunnel with a folding knife, then rides to Budapest for forged papers. His contact, the counterfeiter Laszlo Szabo, recognizes him and drops him through a trapdoor into a sealed cistern. Trapped, Court builds an improvised explosive from disassembled ammunition, floods the pit by cutting a hot water pipe, and blasts through the hatch just as a CIA tactical team and Indonesian commandos converge on the building, fighting each other. Szabo dies in the crossfire, and Court flees into the streets.
He crosses into Switzerland and reaches a hidden weapons cache in a cabin above the village of Guarda. A Libyan kill squad, guided to the exact coordinates by Lloyd's team, attacks at predawn. Court escapes on a snowmobile but loses nearly all his weapons. The attack confirms his suspicion: Only Fitzroy knew about the cache, meaning his handler has been betraying him all along.
Lloyd moves the command center to Château Laurent and speaks directly with Court, threatening to release classified files of every Special Activities Division (SAD) operative, the CIA's covert paramilitary arm, unless Court arrives by eight a.m. Sunday. He also threatens to kill the twins. Fitzroy attacks Lloyd and is chained to a chair and stabbed in the legs. Riegel arrives, appalled, and takes charge of the château's defenses and the hostages' welfare. Claire, the more observant of the twins, attempts to flee the grounds to seek help. Her father Phillip charges after her, and a Belarusian sniper in the tower shoots him dead. Riegel promises Fitzroy that Elise and the twins will be unharmed.
Court reaches Geneva and visits Maurice, his former CIA instructor, a dying Cold War veteran who provides cash, weapons, a satellite phone, and a Mercedes sedan. When a South African hit squad closes in, Maurice, who is terminally ill, insists Court escape and rigs his gas stove to explode, killing himself and all six attackers.
Driving north, Court calls Riegel and proposes releasing the Fitzroys and surrendering the SAD files in exchange for Court killing Lloyd and sparing Riegel. The German declines but deduces that Fitzroy has been smuggling intelligence via a stolen phone and confiscates it. In Paris, a French watcher spots Court, and all kill teams converge on the Left Bank. Song Park Kim, a South Korean intelligence assassin sent as part of Riegel's manhunt and working alone without a support team, ambushes Court in an alleyway with a knife. Court kills Kim but is gravely wounded. Pursued by multiple squads, he drops from the Pont Neuf bridge into the Seine, hooks onto a passing barge, and collapses on the riverbank.
His satellite phone rings: Claire, calling on a phone her grandfather obtained from a sympathetic Scottish guard named McSpadden, asks Court to promise he is coming. He promises. Fitzroy directs him to a veterinary clinic where Justine, a young French assistant in Fitzroy's network of contacts, steals surgical supplies and sutures Court's wound by flashlight as he drives through the night toward Normandy. He passes out at the wheel near dawn and wakes just before seven, less than an hour from the deadline.
Near the château, Court kills a four-man Kazakh patrol, dons their body armor, and climbs over the perimeter wall at seven forty a.m. He sprints across open ground under fire from the tower sniper and rooftop defenders. Libyan and Sri Lankan squads attack through the front gate simultaneously, and the property dissolves into a multi-faction firefight. Court enters the château and fights his way to the third-floor control room, where Lloyd shoots Riegel in the chest and escapes. Court destroys the communications equipment and burns the SAD files in the fireplace.
He finds the Fitzroy family barricaded with McSpadden in a second-floor bedroom and leads them to a BMW in the car park. Lloyd appears and shoots Court in the back; his body armor absorbs the round but drops him. Court orders McSpadden to drive the family away. Lloyd stands over Court to execute him, but Riegel, still alive at a third-floor window, shoots Lloyd dead from above. The two wounded men share a silent acknowledgment before Riegel collapses.
A LaurentGroup helicopter arrives carrying Marc Laurent, the corporation's chief executive, who proposes that Court assassinate former President Abubaker, whose knowledge of LaurentGroup's corrupt operations threatens the company. Court, barely conscious, agrees. Weeks later, in an epilogue set before Christmas, Court meets Claire on a bench in Hyde Park and shows her he is alive. She asks if he killed the people who killed her father; he tells her they will not hurt anyone else. They say goodbye, and Court climbs into a car driven by LaurentGroup operatives headed for Madrid, where he is to kill Abubaker that evening. A French handler calls Court the corporation's property. Court suppresses his anger and gazes out at ordinary London lives as the car carries the Gray Man toward his next kill.