Through a series of oral interviews, it was the story of the global war against zombies, "World War Z," is told, as compiled by the narrator, an agent of the United Nations Postwar Commission. The story begins in China with the story of a young infected boy who is the pandemic's "patient zero", although the origin of the zombie pandemic is unknown. It is implied that the boy was not the first victim chronologically, but his situation marked the point the Chinese government attempts to contain the infection and concocts a crisis involving Taiwan to mask their activities. The infection is spread to other countries by the black market organ trade and by refugees, with a larger outbreak bringing the plague to public attention.
As the infection spreads, Israel abandons the Palestinian territories and initiates a nationwide quarantine, closing its borders to everyone except uninfected Jews and Palestinians. It then puts down an ultra-Orthodox uprising, which is later referred to as a civil war. Pakistan and Iran destroy each other in a nuclear war after the Iranian government attempts to stem the flow of refugees fleeing through Pakistan into Iran. The United States of America does little to prepare because it is over-confident in its ability to suppress any threat. Although special forces teams contain initial outbreaks, a widespread effort never starts as the nation is deprived of political will by several "brushfire wars", and because a rabies vaccine, marketed as effective, creates a false sense of security. When the world recognizes the true extent of the problem, a period known as the "Great Panic" begins. Following the loss of New York City, the U.S. Army sets up a high-profile defense at Yonkers, New York. The U.S. military uses cold war tactics, such as anti-tank weapons and demoralization through wounding; but these prove ineffective against zombies, which "can't be shocked and awed", have no self-preservation instincts, and can only be stopped if shot through the head. The soldiers are routed on live television, while other countries suffer similarly disastrous defeats, and human civilization teeters on the brink of destruction.
In South Africa, the government adopts a plan drafted by ex-apartheid government official Paul Redeker, which calls for the establishment of small sanctuaries, and leaves large groups of refugees abandoned and alive in special zones in order to distract the undead, allowing those within the main safe zone time to regroup and recuperate. Governments worldwide assume similar plans or relocate the populace to safer foreign territory, such as the complete evacuation of the Japanese Home Islands. Because zombies freeze solid in the cold, many civilians in North America flee to the wildernesses of northern Canada and the Arctic, where some 11 million people die of starvation and hypothermia. It is implied in an interview with one survivor that some turn to cannibalism to survive; further interviews from other sources imply that cannibalism occurred in areas of the U.S. where food shortages occurred. The three remaining astronauts in the International Space Station survive the war by salvaging supplies from the abandoned Chinese space station, and maintain some military and civilian satellites using various pods attached to the ISS and the orbital fuel station. A surviving member of the ISS crew describes "mega swarms" of zombies on the American Great Plains and Central Asia and how pollution affected Earth's atmosphere. The United States eventually establishes safe zones west of the Rocky Mountains, and spends much of the next decade eradicating the pandemic in that region. All aspects of civilian life are devoted to supporting the war effort against the pandemic. Much of it resembles total war strategies: rationing of fuel and food, cultivation of private gardens, and civilian neighborhood patrols. The U.S. government also initiates a "Re-education Act" to train the civilian population for the war effort and public humiliation as punishment for criminals in order to restore order.
Seven years after the start of the zombie pandemic, a conference is held off the coast of Honolulu, Hawaii, aboard the USS Saratoga, where most of the world's leaders argue that they can outlast the zombie plague if they stay in their safe zones, but the U.S. President argues for going on the offensive. Determined to lead by example, the U.S. military reinvents itself to meet the specific strategic requirements of fighting the undead: using semi-automatic, high-power rifles and formation and volley firing; focusing on head shots and slow, steady rates of fire; and devises a multipurpose hand tool, the "Lobotomizer" or "Lobo" (described as a combination of a shovel and a battle axe), for close-quarters combat. In three groups (north, central, and south), the U.S. Army traverses the continent in a three-year campaign, systematically destroying the zombies and reclaiming outposts of survivors. Fully automatic weapons, tanks and mobility only return for urban combat or to retake secessionist zones, such as those in the Black Hills.
Ten years after the official end of the zombie war, millions of zombies are still active, mainly on the ocean floor or on snow line islands. A democratic Cuba has become the world's most thriving economy and the international banking capital. China has also become a democracy, following a civil war sparked by the collapse of the Three Gorges Dam and ending after a mutinying Chinese Navy submarine destroys the Communist leadership with submarine-launched ballistic missiles. Tibet, freed from Chinese rule, hosts the world's most populated city. Following a religious revolution, Russia is now an expansionist theocracy. Owing to the fact that many young women either became zombies, infected with HIV or died due to drugs, the Russian government has initiated a "breeding" program, with the remaining fertile women coercively impregnated to increase the population. North Korea is completely empty, with the entire population presumed to have disappeared into underground bunkers. Iceland has been completely depopulated, and is the world's most heavily infested country. The situation in the British Isles is not entirely clear in the novel. It is strongly implied that Ireland has avoided any major outbreaks and that it has also been reunified, due to the lack of distinction between Northern Ireland and the Republic. However, the United Kingdom is described as intact,[2] and now exports oil from a reserve under Windsor Castle. Further confusion surrounds Wales which is described as now including Ludlow, England.[3] Several countries are described as having revised borders due to the "dumping" of convicts into infected zones. These convicts rose to command "powerful fiefdoms" that later became independent states. The Israelis and Palestinians have made peace and Israel and its former occupied territories have been renamed "Unified Palestine". For unknown reasons, the oil fields in Saudi Arabia have been destroyed by the Saudi royal family. Mexico is now known as "Aztlán" (it is not specified whether this is just a change in name alone, or whether any land has been added or lost). There is also mention of a "Pacific Continent," which appears to encompass previously uninhabited islands as well as ships rendered immobile due to lack of fuel. In France, Versailles was the site of a massacre and been burned to the ground. French military losses were particularly high clearing the catacombs underneath Paris, due to the fact that the catacombs housed nearly a quarter of a million refugees during the early stages of the war, all of whom became zombies. The United Nations fields a large military force to eliminate the remaining zombies from overrun areas, defeat hordes that surface from the ocean floor, and kill frozen zombies before they thaw. The human population is hinted to have neared extinction, and many animal species have been devastated, as much by humans as by zombies.
