The film begins by showing the previous six months in flashbacks. In June 2011 a plague called the VM2 virus is first discovered in a French woman. Within the next 28 days, 83% of the population of Europe was infected. The virus becomes a global pandemic as it eventually reaches Japan, Philippines, and the United States. Six months later, the Zombie (fictional) Plague (disease) has wiped out ninety percent of the population of the United States.