The City of Ember (The First Book of Ember), by Jeanne DuPrau
I have now read "The City of Ember" five times, and I enjoy it more with each reading. The world is vivid, the characters are lively, and the entire premise is fascinating.
The premise of "The City of Ember" is that before an as-yet-in-the-series-undefined apocalyptic event of some sort, a group of people were sent into hiding in an underground city, called Ember, to ensure the survival of humanity. They were given enough food, clothing, and, since they were underground, light bulbs to support them for approximately 225 years. The Builders also set up a greenhouse and an elaborate hydroelectric generator, both also designed to last for around 225 years. The instructions on how to leave the city were given to the mayor of the city and handed down from one mayor to the next. The box that contained the instructions had a timer that was set to open the box. However, approximately 75 years before the box was set to open, a plague swept through Ember. The seventh Mayor became fatally ill and in desperation tried to open the box early in hopes that it contained a cure for the illness. He failed to open the box, and the box ended up shoved in a closet and all but forgotten.
Our story opens approximately 90 years later -- around 16 years after the mayor of Ember was supposed to be given the instructions. I keep using the words "approximately" and "around" because at some point, people were in charge of keeping track of the days and sometimes they would forget to advance the calendar, so no one is entirely sure what day, month, or even year it is anymore. Supplies are running out. Lina, one of the protagonists, has been told that there were all sorts of foods that she has never had -- one of those are cans of something called "pineapple" -- and that some of the plants in the greenhouse are starting to get some kind of blight. Light bulbs are in such short supply that they are now being rationed. The generator that powers the city seems to be on its last legs, as well; there are power outages, which are getting more frequent, and getting longer.
The protagonists of "The City of Ember" are Lina Mayfleet and Doon Harrow. As the book opens, Lina and Doon are 12 years old. In Ember, students attend school until they turn 12. At this point, they get their first jobs with the city, which are drawn by lots. The storyline picks up on Selection Day. Lina ends up working in the Pipeworks, and Doon gets the position of Messenger. Lina truly had her heart set on being a Messenger, and Doon wants to help fix the city, so they switch jobs. Through the eyes of these two characters, we see much of the City of Ember, both on the street level and the underpinnings.
Lina, it turns out, is descended from the seventh mayor, and the box containing the instructions on how to leave Ember was in a closet in her home. Lina finds the instructions only after her little sister, Poppy, has gotten hold of them and chewed them up. She can see that they are instructions of some sort, and she enlists Doon in figuring out what they mean.
There is a subplot involving smuggling of rare items. Additionally, some of the people of Ember believe that the Builders will be coming soon to save them. Meanwhile, Lina has been dreaming of another city -- a city that is as light as Ember is dark. She believes that her city exists somewhere, if only she can find the way to get there.
Speaking of Lina's dreams of another city and the belief that they will be rescued from the city soon, the idea that humans -- some humans, at least -- have a mild precognitive ability runs throughout the entire "Books of Ember" series. I actually have a sort of fear of the end of the world left over from my youth in the 1980s, and as a result, I have trouble reading books in which the world ends on-screen, so I have only read three of the four Ember books. The one I haven't read, "The Prophet of Yonwood" involves a woman having a premonition of the end of the world. This premonition is the reason that they built Ember in the first place.
DuPrau did a wonderful job building Ember. It is clear that she did a lot of thinking about how Ember should work. I have to admit, though, that I wonder what kind of canning process the Builders used that the food is still reliably good after over 200 years. Nowadays, 200-year-old cans of food would contain more than a few unpleasant surprises.
I have to caution the reader not to rely on the movie for any of the details of the book. Pretty much the only parts that are the same are Lina's and Doon's jobs and most of the plot about the instructions. For example, Doon's father does not know anything about the Instructions, there are significant differences between the Instructions in the book and in the movie, and there are no giant anythings, much less moths and moles. Read the book; it's much better than the movie.