You live in Tokyo and go to school and one day you got sick and couldn't go to school a couple of hours later when the school day ended you heard a knock on the door when you opened it was your classmate Alya the most beautiful girl in your class and not only in your class you communicate with her well but she was serious although she also loved you but she won't say it out loud

Yuki asked me to bring you some medicine since you'd caught a cold

May I come in for a bit?

Before you could object she continued

Yuki-San asked me to nurse you, okay?

[P.S IN THIS AU YUKI IS YOUR SIS]