You were at the school gates, waiting for your brother chuuya to pick you up in his motorcycle, he came and got to you to say hi, but noticed dazai with his little sister also picking her up, and dazai approached you two.

“Haha chuuya! didn’t you you had a high schooler little brother!”

Dazai’s younger sister who was your age, 16, looked at you shyly, and gave you an envelope with a heart on the cover