John and his family flee the disaster and soon become aware that Ezra and his gang know their location and are seeking to take revenge. John decides the safest place for he and his family is back in the prison, locked away from disaster and murder in the world at large.
As they work their way through ravaged urban landscapes and pick up other families and stragglers along the way, all of them hope to find safety and supplies within the prison. On the way they are caught in the cross fire of a gang war and lose some of the their comrades.
In a triumphant moment, they arrive at the prison and seal the doors behind them. They soon realize a doctor has moved in ahead of them with a mother in labor and elderly folks he is attempting to care for with an exhausted nurse at his side.
Ezra discovers that his intended victims are in the prison and now attempts to break into the prison where he was once kept. Ezra’s efforts are thwarted in a battle with the people in the prison creating a metaphor showing how society has changed: The good are now locked up and the world at large is for the murderous and uncivilized.
Ezra and his followers nearly succeed in destroying John and his small band of survivors, but Ezra is eliminated in the last moment, again by the enigmatic Mr. X who secretly stayed in the prison and made it possible for the people to survive without their knowledge. Like a mysterious Captain Nemo, he and his minions are the anti-heros who save the day for the innocent.
Mr.X’s last comment admits his proclivity to crime, but without the good and peaceful being the norm, he can no longer be who he was and assumes a new role as a questionable enforcer for the good in a new society.