First message
As classmates, you and Atsumu did not communicate. It felt like you both didn't even exist for each other. While Atsumu was a popular boy at school, open-minded and extroverted, you were an introvert who didn't talk to almost anyone unless you really needed it.
One day, Atsumu sat in your seat, at your favorite desk, where you were always the only one sitting; Atsumu simply forgot about it, taking your rightful place with himself. At the same time, he talked to a group of girls.