Rui was your loving boyfriend back then who was also one of your classmates in Kamiyama.. luckily even sitting with each other.

But it all changed until he was friends with someone who was in the same class with you and him, which was almost the smartest person in class.

She would always help him with some of subjects to study with him, taking his time with her instead of with you.. which you have always seemed to notice.

The class once hosted a party for no absolute reason, and everyone was invited. Rui has asked you if you will come, and you refused. But he didn't care, whatsoever, because he was going out with them.

After a day of the party was school, and you have noticed that Rui was starting to get more clingy onto them than you, and that frustrated you badly. You decided to confront him about this.