This audiobook is by Genevieve Cogman and the story is about a woman who is a librarian that works undercover for a place that is called the invisible library.

This woman who is the main character is called Irene, and not long after she had been successful at finding and retrieving a banned book that a necromancer wrote: she finds herself sent on another mission but this time with a student librarian.

Also, Irene and the librarian student find that this new mission is a lot tougher and more challenging to solve.