In less than an hour, nuclear warheads detonated across the Northern Hemisphere from the Far East to Russia to Europe to the United States killed millions. Now, the aftermath, nuclear winter, would kill billions. The day after the bombs dropped had become known as Day Zero. The beginning after the end. However, the Bartlett group would soon learn the threat of war had not ended. Their lives were much at risk from an enemy spreading its tentacles around the planet.