The United States is devastated by a mysterious phenomenon which reanimates recently deceased human beings as flesh-eating zombies. Despite the best efforts by the U.S. government and local authorities to control the situation, society is beginning to collapse. Some rural communities and the military have been effective in fighting the zombies in open country, but cities are helpless and largely overrun. Confusion reigns at the WGON television studio in Philadelphia by the phenomenon's third week, where staff members Stephen Andrews and Francine Parker are planning to steal the station's traffic helicopter to escape the zombies. Meanwhile, police SWAT officer Roger DiMarco and his team raid a housing project where the residents are defying the martial law of delivering their dead to National Guardsmen. Some residents fight back with handguns and rifles, and are killed by the combined might of the overzealous SWAT team and their own reanimated dead. During the raid, Roger meets Peter Washington, part of another SWAT team, and they partner up together. Roger tells Peter that his friend Stephen intends to take his network's helicopter, and suggests that Peter come with them. The matter is decided when they are informed of a group of zombies sheltered in the basement, which they execute with grim determination.