Two weeks after the infection of Patient Zero, four immune survivors of the outbreak (Francis, Zoey, Bill, and Louis) make their way through the city of Fairfield, only to discover that the virus is creating new, even more dangerous mutations. After narrowly avoiding these new infected, along with hordes of others, the survivors are alerted to the presence of an evacuation point at the nearby Mercy Hospital by a passing news helicopter. Fighting their way through the city's streets, subway and sewers, the survivors are rescued from the hospital's roof by the pilot, only to discover that he is succumbing to the infection. From there, the four survivors make their way from stopping point to stopping point, hoping to escape the Zombie Apocalypse