The City of Ember
by Jeanne DuPrau
A mysterious happening occurs on Earth and makes it impossible for people to live there, thus forcing them to move underground. The underground city is powered by an over sized generator. It is only supposed to provide power for 200 years and time is racing.
All the mayors in Ember had one thing in common, and that was the secret to Ember. The secret was inside the box in Lina's house. It is there because Lina is related to one of the former mayors who had passed away. Lina stumbles across it in her closet and realizes that there is a map. You can barely see what it says, but it's up to Lina and her best friend Boon to read it and maybe find a way out of Ember.
-N. Ortega