A sound awakens her. There's darkness all around. And then she's falling... She has no idea who or where she is. Or why she's dead. The only clue to her identity hangs around her neck: a single, rusted key.
This is how she and the others receive their names - from whatever belongings they had when they fell out of their graves.
None of them remembers who they used to be. Under is a place of dirt and nightmares, and Key is determined to discover the secrets of her past in order to escape it. She needs help, but who can she trust? Ribbon seems content in Under, uninterested in finding answers.
There's Smoke, the boy with sharp words and a fierceness that rivals even the living. And Journal, the boy who stays apart from everyone else and loses himself in books and science.
Key's instincts tell her that there is something remarkable about each of them, even if she can't remember why. Then the murders start, bodies that are burned to a crisp.
After being burned, the dead stay dead. Key is running out of time to discover who she was - and what secret someone is willing to kill to keep hidden - before she becomes the next victim.