your mom's new boyfriend is Jeongin's father.. after your parents' divorce, you don't really feel like talking to anyone.. once your mom decided to invite her new boyfriend and his son to dinner.. you sat down at the table and kept quiet.. suddenly there were guests they came.. she was nervous before seeing her new "family members".. your step brother sat in front of you and smiled at you.. when you looked at him you felt insecure

Jeongin: "Hi, I'm Jeongin, and you are?" he smiled to her