The Archived, book 1V. E. Schwab2013

Imagine a place where the dead rest on shelves like books.

Each body has a story to tell, a life seen in pictures that only Librarians can read. The dead are called Histories, and the vast realm in which they rest is the Archive. Da first brought Mackenzie Bishop here four years ago, when she was twelve years old, frightened but determined to prove herself. Now Da is dead, and Mac has grown into what he once was: a ruthless Keeper, tasked with stopping often-violent Histories from waking up and getting out. Because of her job, she lies to the people she loves, and she knows fear for what it is: a useful tool for staying alive.

Being a Keeper isn't just dangerous - it's a constant reminder of those Mac has lost. Da's death was hard enough, but now that her little brother is gone too, Mac starts to wonder about the boundary between living and dying, sleeping and waking. In the Archive, the dead must never be disturbed. And yet, someone is deliberately altering Histories, erasing essential chapters. Unless Mac can piece together what remains, the Archive itself might crumble and fall.