City of Ember (2008)

For generations, the people of the City of Ember have flourished in an amazing world of glittering lights. But Ember's once powerful generator is failing . . . and the great lamps that illuminate the city are starting to flicker. Now, two teenagers in a race against time, must search Ember for clues that will unlock the ancient mystery of the city's existence, and help the citizens escape before the lights go out forever.