City of Ember (2008)

A science fiction directed by Gil Kenan, starring Bill Murray.
Because of a nuclear war, an underground city was constructed. A box with instructions on how to get out has a 200 year timed lock on it. The box is eventually forgotten, so nobody knows when the lock opens. Many years later, children find the box and it's exit instructions.
This was so sappy and overproduced that I'm surprised it isn't Disney. It's really a kids film, but this fact is not given anywhere. I thought the characters were shallow and the plot a little trite. The style seemed like a combination of Disney and Scifi channel presents... I'm rating it o.k.