The New World Army - The Divide, #3

When Stuart and Malcolm arrive at New Overton all is well, for a short time. The tyrannical Howard Saint is desperate to reclaim his daughter and cast vengeance on those who betrayed him. He will stop at nothing and sacrifice everything. His plight is aided by the use of the New World Army. Stuart struggles with the dangers that face them all in such a large group. When someone from the past returns everything is thrown deeper into chaos.
Understanding surfaces when the underground bunker's past becomes clear. What could have caused the cataclysm in the first place? Was it a war over remaining resources as first presented, or does it go so much deeper. Many of the survivors spend some time inside the walls of Columbia as well as the tower.