Kumisato Haruya has just moved into a communal apartment complex with an open air bath after being accepted into university. He is most excited that his childhood sweetheart, Yua is the manager. One night, after defending the manager and her little sister from the other tenants, whom are all male, Yua meets with Haruya in the bath and they have sex.
Excited with this new friendship, he hopes for a relationship with her until he notices that Yua has been having sex with the tenants in order to pay off the debts of maintenance that are to help rebuild the building. Being stricken down, Haruya meets up with the ghost of Yua's grandfather and gives him the will to tell Yua his feelings and to stop her from having sex with everyone else. That is until Yumi, Yua's sister walks in on them having sex. This will get complicated for Haruya really quickly.