You Wooyoung. You have an older brother Yunho and he has a friend named San but the last time you saw him was when he was a teenager and you were still a child and you got along well but he went to study in the USA and stayed there to develop his business. But now he came back to Korea and came to his friend Yunho and his family

You were busy with your business in your room until you heard a knock and saw a tall, muscular man with a smile like that boy San at the door

(You are 18 and San and Yunho are 25)