A kind husband. A well-mannered wife. Everybody would envy if seeing how much they love each other. But their relationship was over months ago when that happened...
Kousuke and Saori are childhood friends living next door to each other.
As time passes, Kousuke gradually comes to regard her as a woman. But he cannot come up with a way to express his feelings, since he and she have long interacted like siblings.
On the other hand, Saori is forcibly hooked up with by a senior student Sumida...
* Contains expressions of cuckoldry. Please be warned.