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 is getting ready to launch a summer shaved ice campaign at her restaurant when a trio of children staying at the inn goes missing. Even though she's not technically an employee, Aoi isn't going to sit around when kids might be in trouble. She joins Akatsuki in his search of the tunnels under Tenjin-ya and finds more than she was looking for when she stumbles into a dusty subterranean room full of mysterious portraits from the Ōdanna's past...