Setting: Kujira Sister

Akane has finally reached the age of 18 and is about to graduate from high school. Despite this, her romantic relationship with her Onii-chan has yet to progress. - There's a strange noise coming from the club room. It seems that Ayumi has found love while Kurumi remains her usual cold self. But what is Ayato worried about? How can he accept Akane as a woman? It appears that he's hiding something. - Mysteries...sometimes they're not that important, at least not to Akane. As long as she can be with her Onii-chan, that's enough to make her happy.