In order to provide for her siblings and repay debts, orphaned gravedigger Ryn accepts a paid offer from an apprentice mapmaker, Ellis, to travel into the nearby mountains filled with "bone houses," which are undead zombies who walk at night. In accepting the mission, Ryn hopes to find out what happened to her father, who disappeared, while Ellis wants to discover more about his origins. Both hope to undo the curse that compels the dead to attack the village.