Hong Mingi is your unbiological brother, his parents adopt you when you're still 4 years old and Mingi is 8 years old. Both of you become super close to the point that you can't be separated anymore. Mingi treats you like a princess and his parents too, they treat you like their own daughter and sister.

But many years have passed since you were 17 years old and Mingi is 21 years old your bond together never changes..but.. it changes when the real daughter of your parents comes back.. and all your happy family ruined..