On a spring day, 1.8 billion children disappear from the face of the earth and natural disasters rock the globe. Of those who remain, 90 percent are ravaged with a plague that turns them into mindless, murderous beings. When the walls of Grace crumble at the hands of the Sleepers, those who survive are forced to flee. They move east to beyond the Great Divide and find refuge in a former Juvenile correction facility in Ohio. The loss of their home is great, but even greater is the loss of one of their own. While they struggle to overcome their heartache, they still must prepare for the Sleepers. The Sleepers grow in numbers, massing together. They are deadly and more frightening, they are starting to plan. Not only do the survivors have to face the deadly force beyond their fence, unknowingly, an even deadlier force lurks among them.