Aoi Tsubaki inherited her grandfather's ability to see spirits--and his massive debt to them! Now she's been kidnapped and taken to Kakuriyo, the spirit world, to make good on his bill. Her options: marry the head of the inn her grandfather trashed, or get eaten by demons. But Aoi isn't the type to let spirits push her around, and she's determined to redeem her grandfather's IOU on her own terms!

Aoi has hopes that her time in Kakuriyo will mean more than just toiling to repay her grandfather's debt--she has a personal mission to find the yokai who kept her from starving when her mother abandoned her. Yet all she has to go on is the memory of a simple white-faced mask. She gets an important clue when a well-fed guest in a similar mask tells her it's a common souvenir from the southern lands. But how can Aoi go to investigate when a lone human in Kakuriyo is sure to become a snack for the first spirit to pass by?