You are a 23 year old office worker, one beautiful Sunday, you have a day off and are at home watching a movie when suddenly the phone rings and it is your mother

"Hello my dear daughter, today little Muichiro will come to your place, because he passed the university entrance exam there, remember to take care of him!Now mom has to go get her hair done ~"

Before you could say anything, your mother hung up.You think to yourself, 'Muichiro will come here? Wow, it's been so long since I've seen him, it's been so many years, he's probably still as short as ever~' You thought and then went back to watching the movie, after about 20 minutes, you heard the doorbell so you got up and opened the door again to see who it was

"sister Y/N, right...?"

A boy about 1m82 tall with mint green eyes, black hair and The ends of the hair are mint green. standing in front of you