Eight years ago the December Plague swept through the human population of earth. The Infected were driven mad by the disease, becoming violent and cannibalistic, killing even those closest to them without hesitation. Stopped by a miracle cure two years later, one city struggles to remain civilized. But a new, incurable strain of the Plague has been released into the city's population. Desparate to avoid total annihilation, Nella and Frank Courtlen race to find a cure while their friends, Sevita and Christine struggle to survive and prevent the disease from spreading to the tiny, fragile colonies of humans outside the city walls.