The Books of Ember is a four-book series about the adventures of Lina Mayfleet and Doon Harrow, who live in the Underground City of Ember, which relies on lightbulbs to keep the town lighted and running. However, the lightbulbs are beginning to dull and food/rations are running out in the city; it won't be long until the entire city is cloaked in eternal darkness and becomes poverty-stricken. One day, Lina finds a letter (which is unrecognizable at first because her little sister Poppy chewed on it), which may possibly lead the citizens out of Ember. However, Lina and Doon have to confront a conspiracy that wishes to keep the truth under wraps... Books in the Series
Accidentally Broke the MacGuffin: In the fourth book, Doon throws the diamond of Darkhold at a pack of wolves to save Lina. The diamond hits the rock that Lina is standing on and shatters into hundreds of pieces. Luckily, The diamond is only a sample. There are exactly one thousand diamonds in a hidden room in the cave. The diamonds are ancient technology that turns solar power into electricity.
An Aesop: The second book's underlying theme is basically learning to accept people who are different from you.
America Saves the Day: Very subtle, but think about it. Americans built Ember, Americans populated it, and Americans provided the revolutionary solar-power diamonds that pave the way to the future. Perhaps one of the few non-war examples. Also ironic in that America helped cause the Disaster.
Apocalyptic Log: The journal Doon and Lina find while on the raft, leaving Ember. The log is shown to be the work of an elderly Nickie, the protagonist of Yonwood.
Apocalypse How: On the surface world, it's about a class 1, with a dash of class 2 in some places. Ember is basically untouched by the Disaster though.
Asshole Victim: In the film the Mayor gets eaten by a giant mole after he gets into what he thinks is a safe room. It's hard to feel sorry for the Jerk Ass.
Crapsack World: Played with. Ember was once a nice place to live in, and even on the surface world people seem to generally get along with one another. (with the exception of the 2nd book, but that was partially because the Emberites didn't know how to do anything.) By the end, society has been completely rebuilt into a utopia.
Crying Wolf: Subverted; the mayor stated that Doon and Lina were lying about the route out of Ember to keep everyone under his reign.
Arguably, the plans set by the Builders themselves could also qualify. Going through all the trouble of keeping the true contents of the box a secret. Or seeing to it that no one knew the history of the world leading up to the disaster in an attempt to start from a clean slate.
Karmic Death: In the film, the Mayor is eaten alive after locking himself in a room filled with food. In the books, it's revealed that he drowned in the river while trying to leave Ember ahead of everyone else. Still counts, though.
Maybe Ever After: A single line at the end of the 4th book hints that Doon and Lina might be falling in love with each other. There's no further mention of them after that.
It mentions that they end up sharing a house, so it's safe to assume that they probably did end up together.
The troublemaking Emberite kid featured in Sparks is named Tick Hassler.
The terrorist nation in the 3rd book is called the Phalanx Nations.
In a way, Ember itself. Its supply of stored food is finite, as is the stock of light bulbs (and thus the operability of the greenhouse). To make matters worse, the Generator is gradually breaking down, causing increasingly frequent blackouts.
Lina Mayfleet, as she wanted to be a messenger, which requires her to be fast.
Missing Mom: Doon's mom is never mentioned in the series, not even once; some fans assume that she died when Doon was a baby/young.
The Outside World: This is the ultimate destination for Doon Harrow and Lina Mayfleet, recognizing that the limited lifespan of The Books of Ember is winding down. It's an uphill struggle against Ember's corrupt mayor to navigate the exit sequence engineered by the city's original builders.
Averted with Ember itself, which was originally designed to function for 200 years and looks like it's literally about to fall apart. There's evidence suggesting however that things were starting to deteriorate even before then.
Reptiles Are Abhorrent: Mrs. Beeson indirectly cites this trope when Nickie tells her that Grover owns snakes in his shed.
Scavenger World: The surface world has this as its main economy. Ember began to turn into this by the end as well.