The first volume of a manga series.
After the death of the wayward grandfather who raised her, Aoi is going to college -- and feeding the ayakashi she meets along the way, even though her ability to see them has led to people to think she's crazy.
She meets an unusual one, as large as a man, and gives him food as well. And thus is dragged off to an inn, where the unusual one proves to be an ogre (oni, I presume) and wants to marry her -- which her grandfather had promised to pay off a debt. She'd rather work it off.
It involves not being pretty enough to be a waitress, a fox with nine forms, a tea house that can't stay open, those jealous that the ogre wants to marry her, cooking, and more.