After the destruction of Sanctuary, the group continues on in search of a place they can call home. They need a place to prepare for the upcoming winter, but they want a place they can build more. The group fights to survive. With encounters from unexpected visitors, the past coming back to haunt them, and the group forced to divide, all of which proves to be a challenge.

An unusual chain of events scatters the group across a small area of the Divide. Some wind up in protected communities, while others are left to fight off the dangers of the Divide on their own. This book will introduce more of the Divide and delve into some of the darker parts of human nature. Some of the people they meet want a better world for all, some want a better world for themselves and a select few, and others adapt to the evil and a gruesome reality that makes living in the Divide even more dangerous.

All the characters must face some revelations about their circumstances or their emotions. Stuart must face the fact that he is not as cold and shutoff as he pretends to be. Coach must deal with the family he inherited and try to somehow keep them together. Ariana must deal with her past secrets and the consequences once they are brought to light.

Kim and Sophie are both forced to grow up some more in a short time. Kim needs to reign in her jealousy of those around her, which forces her to address her true feelings about living alone in the Divide and Malcolm. The history of the Divide begins to unfold in the sequel to Cataclysm. Will the group ever find a safe place? Will they find each other? Will America start to rebuild? What secrets will come to light as the group presses on?

In The Tower, the world just got a lot bigger, and this small group has to stand together or be swallowed up.