Months after the death of her fiance, Grace stumbles upon a mute and inexperienced survivor, Oscar. The unlikely duo travels across a barren landscape in hopes of survival, but Grace's past lingers behind them like a dark shadow.

In the future, a second great flood covers most of the known world. Country borders collapse and language barrier disappear. All salvageable books are taken to a deep underground vault facility for protection. Run by priests, the facility is called The Stacks. As Olivia wanders the facility she discovers that she may not be alone and that a dark part of her past may have followed her into the narrow corridors of this inescapable purgatory.