Harold Harbinger works with a special team of ornithologists to find an antidote for parrot fever, a life-threatening bacterial disease that kills both birds and humans if left untreated. He unwittingly brings home a mutated form of the bacteria and infects his beloved wife, Margaret. She dies, but a short hour later "turns" and becomes a zombie with bird-like characteristics and begins the killing spree that will soon be commonplace in her hometown. As more members of the community acquire the disease from bird droppings Southern California is taken over by utter mayhem. The infected roost in trees at night and seek out victims by day. These undead think like birds and are able to outmaneuver the police and military. The officials sent to control the hordes work together to suppress the mass violence while Harbinger and his team of researchers brainstorm to find a cure. Harold's precious African Grey Parrot, Plato, also infected by the bacteria, could hold all the answers.