Lina and Doon are thrilled to see their people join them above ground in the vibrant village of Sparks, but suspicion and prejudice soon turn the villagers and newcomers against each other.
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.