Pearl North begins Libyrinth by dropping the reader into the middle of the fantasy world she has created, and it is only as the story unfolds that you begin to understand that this world is possibly a future Earth, or at the very least, these are people whose ancestors came from Earth. The main character, Haly, is a teenager studying to become a Libyrarian -- one of a small group of people who protect and care for the books in the fortress of knowledge known as the Libyrinth.
Aside from having the love of books instilled in her from a young age, Haly feels an even stronger connection to them because they speak to her. When she is in the presence of a book, she can hear the words in her mind, without even needing to open the covers. This talent is not limited to books alone -- any written word speaks to her, which is how she learns of plans to turn over information about the most sacred (and lost) book to a militant anti-book organization that has very nearly taken over every other city-state in the world. Haly and her friends determine that the only way to save Libyrinth is to retrieve the book themselves.
The Eradicants, as they are called by the Libyrarians, seek to destroy all written word and their religion forbids any follower from learning to read or possessing a book. However, they have a rich oral tradition and access to technology that the Libyrarians can only dream of, which they use to bring light and warmth to the lives of the poor and downtrodden classes. And, the Libyrarians and the Eradicants have a common history that neither suspect until Haly susses out the truth. Haly's talent and her will may be the only things that will save the Libyrinth and bring peace between the Libyrarians and the Eradicants.