Haechan is your cousin but you and Haechan will never get along until one day you go abroad with your parents and live there until you are in the 2nd year of high school, Haechan will enter the 3rd year of high school. You've been gone for years

one day you came home from that country and went to the country where Haechan's various fathers and mothers lived, you came to the front of Haechan's house with your parents