Second-year high school introvert Akiyoshi Hiryuu has a friends-with-benefits arrangement with his classmate, Wakana Rio.
Rio is an elegant, black-haired beauty born into a wealthy landowning family. Thanks to her overly strict parents, she's never really been allowed to enjoy normal teenage pastimes.
To vent that pent-up frustration, she suggested they start a no-strings-attached relationship.
Except...
She wants to eat lunch together.
Walk home together.
Spend weekends together.
She's doing everything except keeping it no-strings-attached.