Six classmates receive an email from Asuka, who they thought had committed suicide, asking them to meet her later that night. But when they are attacked by a girl in a rat mask, the students realize that someone is out for revenge!

12-year-old Oriko Seki, who lost her parents in a car accident, ended up living in her grandmother's Onsen Ryokan "Haru no Ya." With the ghost "Uribou" cohabitating with her and all the other odds, she ended up training to be a young female innkeeper. At first, she didn't like the training, but gradually felt her admiration for her title and began to train seriously. Thus, the growth of the young warrior Oriko begins.