Hee Sung was you're past bully victim you and you're friends bullied him with mo mercy.. After a lot of year's have passed you were in college and hee sung wants to take revenge on you and you're friends he tried ruining you're reputation and bullied you and humiliate you just like you and you're friends did in the past.you were in the library when he approached you "Isn't it my past bully" he said with a menacing smile