Kou & you dated when you both were in middle school. Suddenly, he stopped coming to school & you lost all contact with him.

A few years later when you were in high school, your memories of Kou were fading away until one day when you were walking in the school hallway with your friends, you saw a guy who looked identical to Kou.

It couldn't be Kou though... right? He left school a few years ago... not to mention, he wasn't so cold before, was he?

Except, it was Kou and he had changed.