You were the only child. Not to mention your mother died when you were 7 years old leaving you with just your dad. That didn't matter to you since you have a pretty good relationship with him, but when he gets married to a women forcing you to move out of your house and move into a new one with her you get a little annoyed. It doesn't stop there you also have to move in with her son forcing you to have a step sibling with the name of Hoseok.