Countdown

On May 22, Amy Cornwall, a former U.S. Army captain now serving as lead officer for the CIA's Special Activities Division, commands a joint CIA and MI6 (Britain's foreign intelligence service) sniper mission in Lebanon's Anti-Lebanon Mountains. The team eliminates two Abu Sayyaf terrorist leaders, but the MI6 operatives, shooter Jeremy Windsor and spotter Oliver Davies, radio that hostile fighters are pursuing them. Amy's CIA teammates reach the extraction helicopter, but Amy holds it past the departure deadline. When the British team fails to appear, Amy goes back into the mountains to find them.

Jeremy and Oliver have been captured and taken to a militant farmhouse, where Oliver is beheaded by an older man wielding a curved sword. Before turning to Jeremy, the swordsman whispers in Oxford-accented English, "You should have stayed home, Jeremy" (28). Amy's team storms the courtyard just in time: A sniper shot knocks the sword away, and Amy and her teammates kill the remaining gunmen. The swordsman escapes. Jeremy destroys the execution video but does not tell Amy what the man said.

A British Petroleum helicopter arrives for extraction. Amy's teammates board, but Jeremy turns away. Amy jumps off to stay with him, insisting she remains in command. Jeremy reveals that he and Oliver allowed themselves to be captured as part of a secondary mission to kill Rashad Hussain, a wealthy Saudi terrorist planning a catastrophic attack on Paris or New York on May 29, the anniversary of the fall of Constantinople. Jeremy warns that Rashad intends to make 9/11 "look like a dustbin fire" (59). The swordsman who killed Oliver is Rashad himself.

Parallel storylines establish the broader stakes. At CIA headquarters in Langley, Virginia, Ernest Hollister, Amy's division supervisor, orders her "smoked," erasing all records of her employment and revoking her access. His assistant reveals that Rashad is a CIA asset on Langley's payroll. At MI6's Lindsay Hall estate in England, veteran officer Horace Evans learns of the capture but refuses Ernest's calls; Oliver's death reaches Horace only later. In Manhattan, Amy's husband, Tom Cornwall, a journalist working out of One World Trade Center, notices unknown watchers surveilling him. Yuri, a foreign correspondent Tom met years earlier while on assignment in Syria and who he suspects of working for Russian or Ukrainian intelligence, warns Tom to leave New York.

Amy and Jeremy fight through Lebanon, reaching contacts who arrange transport to Beirut and a private jet to France. Aboard the plane, Amy discovers she has been smoked: Every CIA channel rejects her. Jeremy reveals they are flying to Paris, where Rashad has been located, and discloses that Rashad murdered both their fathers by sabotaging a private jet.

In Paris, Victor Martin of the DGSE (France's external intelligence service) briefs them: Rashad is expected to receive an RA-115, a Russian-made suitcase nuclear bomb, at an abandoned runway outside the city. Amy warns the operation is a trap. Victor proceeds anyway. When a van drives toward the assault team instead of fleeing, it explodes, killing four DGSE officers and severing Victor's leg. Amy saves Victor's life with a tourniquet and shoots their French bodyguard, who tries to assassinate Jeremy, exposing a mole Rashad planted in the team. The nuke proves to be a decoy, and Rashad escapes.

Separate threads reveal the scope of Rashad's plan. In Paris, Nadia Khadra, a microbiologist at the Institut Pasteur driven by vengeance for her grandparents' killing during a 1961 Algerian protest, has been weaponizing anthrax in her apartment cellar. In Manhattan, Mike Patel, a British citizen working illegally as an HVAC technician at One World Trade Center, has been installing mysterious devices throughout the building. Freddie Farrady, a Scotland Yard detective on a surveillance assignment in New York with Portia Grayson of MI5 (Britain's domestic security service), tracks Patel and grows suspicious.

In London, Jeremy's team tracks Rashad using a classified chip implanted in his wrist. Amy calls Tom on an encrypted line and speaks their prearranged evacuation code word, "Ticonderoga." Tom sends their 11-year-old daughter, Denise, to his uncle's home on Staten Island. A CIA snatch team then ambushes Amy and takes her to a black site in the English countryside. After days of disorienting confinement, she escapes by faking a suicide attempt, overpowering a guard, and fighting her way out. Jeremy, monitoring the site by drone, retrieves her.

They rush to Heathrow Airport but arrive moments too late: Rashad has cut the tracking chip from his own wrist and vanished. Amy tasks Tom with researching Rashad's corporate holdings. Tom uncovers a critical lead: Rashad secretly owns the Hudson Valley Railroad, a freight line from Hoboken, New Jersey, to Albany that consistently loses money. Amy and Jeremy commandeer two Royal Air Force (RAF) Typhoon jets for a transatlantic flight to New Jersey, where a retired railroad enthusiast named Gus Carlucci reveals Rashad's plan. Two Hudson Valley trains, one carrying liquid hydrochloric acid and the other dry sodium chloride, are scheduled to pass each other at 11:09 a.m. on May 29. If rigged to explode simultaneously, the violent chemical reaction will produce massive clouds of lethal chlorine gas. Gus estimates more than 100,000 dead.

On May 29, Rashad's multi-pronged attack unfolds. He watches from a hotel rooftop overlooking the Hudson River. Patel triggers smoke bombs inside One World Trade Center to drive crowds toward the river and the approaching gas cloud while positioning himself to shoot into the fleeing masses from a concealed van. Nadia arrives at City Hall Park with the anthrax, but Patel remotely detonates a bomb hidden in her dress belt, killing her and destroying the anthrax. Rashad always planned to sacrifice Nadia as a diversion. Freddie confronts Patel, whose rifle fails because Freddie previously removed its firing pin. Patel drives his van into the crowds before a fire truck rams him, and Freddie executes him.

Amy and Jeremy split up. Jeremy crosses the Hudson, reaches the hotel, and shoots Rashad in the leg but learns the train bombs use proximity fuses, which detonate automatically when the trains near each other and cannot be stopped remotely. Amy calls Lisa Bailey, an NYPD helicopter pilot who served under her in Afghanistan. Lisa's helicopter stops the northbound train by hovering in its path, but the southbound train continues: one of Rashad's operatives, a Chechen fighter named Alvi Dudin who is working undercover as the train's conductor, has shot the engineer and disabled the safety systems. Amy jumps from the helicopter onto the moving locomotive, shoots her way into the cab, kills Alvi, and pulls the emergency brake. The train slows but passes the stopped northbound train before fully halting. Some bombs detonate, but many fail because the explosives were secretly sabotaged. Gas clouds form but are far smaller than projected, and prior evacuations have cleared much of the surrounding area.

Despite Amy's warning, Denise insists on visiting Tom at One World Trade Center for Take Your Daughter to Work Day. Caught in the stampeding evacuation, Tom and Denise are struck by Patel's speeding van. Both are killed. At the hospital, Amy finds them on separate beds, pushes the beds together, and lies holding Denise while stroking Tom's forehead.

In the aftermath, Jeremy confronts Horace Evans at MI6. Rashad had revealed under duress that Horace's assistant, Declan Ainsworth, secretly guided Rashad for years on Horace's orders, even arranging the train explosives through a supplier who deliberately sabotaged them to limit casualties. Horace's goal was to engineer a near-catastrophic attack that would shock an isolationist United States back into engagement with its allies, the way 9/11 had done two decades earlier. Jeremy secures cancellation of his Faroe order (MI6's threat to imprison him at a remote black site) and a transfer to another section. Amy separately entraps Ernest Hollister by recording his confession that he smoked her to end women's participation in field operations. Her original CIA recruiter lifts the smoke order and gives her three months to hunt everyone who aided Rashad.

Rashad, broken out of his hospital room by mercenaries, recovers at a luxury resort in Bali. One evening he finds his lead bodyguard dead, throat cut, with a note pinned to the body: "RASHAD, YOU SHOULD HAVE STAYED HOME. REGARDS FROM OLLIE DAVIES" (451). One by one, the lights inside his villa go out.