In 1992, a nuclear weapon is smuggled into San Francisco, and hidden behind a Chinese restaurant owned by YAN LONGWEI. It is the first step in a long-range plan devised by LIEUTENANT GENERAL KUNG YUSHENG.
Many years later, AMANDA LANGFORD starts work for the CIA, as an analyst at the Mission Center for Weapons and Counterproliferation. Her new boss, JANET DAVIDSON, gives her 24 hours to review a file, and present her conclusions to department head, CALEB MCELROY. Amanda discovers that China has hidden the production of over one ton of Highly Enriched Uranium.
Longwei's restaurant in San Francisco catches fire. He dies trying to put out the fire, but not before telling one of the firemen, TOM JACKSON, to run away from a bomb. Everyone involved in the incident is held and questioned by the Department of Homeland Security. KATE WILLIAMS, a specialist in nuclear weapons, is sent to San Francisco to disarm the device.
The 50th nuclear device arrives by ship in New Orleans. It is escorted by GONG AIGUO, a First Lieutenant in the Siberian Tigers Special Forces unit. The 10-megaton device, hidden inside an old diesel generator, is transported by rail to the Torpedo Factory Art Center in Alexandria, Virginia. Aiguo makes the delivery, but while contemplating the potential impact of what he has done, he walks off into a blizzard. He gets lost and collapses under an overpass, suffering from hypothermia. He is found and taken by ambulance to a local hospital. A nurse, MEIFENG THOMPSON, recognizes the Chinese Special Forces unit tattoo on his shoulder. She calls her husband, MAJOR ANTHONY THOMPSON, who works in the Pentagon. Aiguo regains consciousness, escapes, and kills five people, including Meifeng.
General Kung is notified by his aide, COLONEL PENG, that the Americans have discovered one of his nuclear devices. Kung decides it is time to notify his superiors of his secret plan.
Aiguo flees from the hospital and contacts his grandfather, Colonel Peng, for help. Peng tells him to go to the house of Caleb McElroy, who is an agent working for Kung. Peng orders his grandson to kill McElroy, who has outlived his usefulness.
Amanda investigates the incident in Alexandria, and becomes convinced that the murders are connected with the device in San Francisco and the missing nuclear material.
Amanda meets with Major Anthony Thompson, who is deep in despair over the death of his pregnant wife. Anthony remembers additional details about the conversation with his wife on the night of the murders.
The Chinese Party General Secretary, LI XIBIN, agrees to support Kung's plan. He contacts the President of the US, and threatens to leak information about the nukes to the press to destabilize US markets, and panic the US people. He demands that the US leave the Western Pacific permanently. He gives the President 48 hours to agree to his terms.
Aiguo kills Caleb McElroy. He then decides to steal McElroy's identity and flee the US. He returns to Alexandria, and decides to wait for his departure flight at Vola's Bar and Grill, near the Torpedo Factory.
Anthony calls Amanda and asks her to meet him behind the Torpedo Factory. Amanda bumps into Aiguo before meeting with Anthony. While talking with Anthony she realizes who she bumped into. When she tells Anthony her suspicions Anthony becomes enraged and confronts Aiguo in Vola's restaurant. A shootout ensues. Aiguo is seriously wounded and captured.
Kate asks the President for more help in disarming the nukes. The Prime Minister of Israel meets with DAVID BARZA, Kate's old mentor and lover, to relay the request. David agrees, and is flown to Alexandria to work on the device there. Kate isn't aware of it, but David is now in the early stages of Parkinson's.
Secret US aircraft are launched from Nevada. They appear over Beijing while Li Xibin is meeting in the Great Hall of the People to announce the withdrawal of the US from the Western Pacific. Another secret bomber, in orbit above China, releases four kinetic weapons that impact in sparsely populated areas of Manchuria. The huge craters form a straight line pointing at Beijing. After talking to the President, Li Xibin backs down from his threats against the US.
Kate flies to Alexandria to help David with disarming the 10-megaton nuke. She and David are in the process of inspecting the device when Kung is notified of Li Xibin's decision and is infuriated. He attempts to detonate all the nukes from a control panel in his office, but is shot by Colonel Peng. He does activate one nuke, the one in Alexandria.
Kate and David have less than three minutes to remove the transmitter from the weapon or it will detonate and destroy Washington, DC. They remove the transmitter with less than five seconds to spare.