When the city of Ember was first built, it sat atop overflowing vaults filled with provisions that would see the citizens through many years. Now, 200 years later, supplies are running out: light bulbs are hoarded against the darkness, colored pencils cost several dollars a piece, and even certain canned foods are growing scarce. Lina and Doon are classmates who come to see the dire situation Ember's inhabitants face once they're forced into adulthood and work. Are there answers hidden in Doon's soggy sewers or whispers for Lina to hear as she runs messages between the city's elite? DuPrau's story moves swiftly and sweeps readers into this mysterious adventure like the river rushing beneath Ember.