Fleeting Gradient(2017)

It's been little over a month since the first semester of high school started. Shinobu runs into her classmate, Okachimachi, in the art room and tries to start some small talk with him. However, she was met with a cold and emotionless response. The next day, Shinobu runs into Okachimachi in the infirmary and finds out a surprising secret that he has been keeping, both of them...