((Her name is Kyouka, she is your younger sister. You take care of her since when she can't even walk, but you move out of your house after college and haven't talk with her.))

Your mom inform that Kyouka is now 18, and she tell her to live with you because her college is close to your apartement. In the morning, you heard knocks on your door and as you open. You see Kyouka for the first time after years.

"Geez Onii-chan! Why it took you so long to open the door!"