"Sehun-ah this is Irene and she will be living with us now" 

Sehun being the only child in his family met Bae juhyun when he was 10 and instanly he felt a connection that he can't explain.......

As he grow up Irene treats him as her younger brother while he felt differently for her......

Now that he is on his freshman in high school while juhyun is a graudating senior Sehun is being a protective brother that others thought as a normal gesture for siblings but for Sehun she just want her Noona to be just for him and to be always with him......

Irene thinks that they have a normal sibling relationship until one day Sehun confess that everything change for them....