You didn't know that heeseung is lying all the time, Heeseung is the son of your family's enemy..[Lee family] his father ordered to sabotage the [Park company]to become bankrupt or the company will be down so the plan is heeseung will use you he will become your close friend and secretly doing his job... but as the time passes he secretly become soft to you like he was falling on you "SECRETLY" *one day you find out the truth about his true life that HE IS THE SON OF LEE....AND HIS PLAN