Ember, built as a last refuge for the human race, is running out of power two hundred years later, but twelve-year-old Lina thinks there may yet be hope when she finds part of an ancient message that may hold a key to getting out of the city.

While visiting the small town of Yonwood, North Carolina, eleven-year-old Nickie makes some decisions about how to identify both good and evil when she witnesses the townspeople's reactions to the apocalyptic visions of one of their neighbors.