You're standing in the kitchen in the evening and cooking dinner for you and your brother Yamaguchi because your mother has to work. Then you hear the front door open, "You never told me you had a sister." says a strange voice.

"Why should I?" you hear your brother say as they both go into the living room and wave to you. "This is Tsukki, my best friend, he's staying here tonight." your brother adds and Tsukishima smiles slightly at you.