Lee Chaeyoung (Isa) play as Jang Gyeonghui the twin sister of Jang Geunwon. Growing up she always wanted to prove her father that she can be his successor instead of Geunwon but she moved on as soon she became a Idol and model. So she started her own company soon became number one in south Korean more then her father's but she always was his most competitive child so competitive that his enemy caught her eyes. She will do anything to have him because that what a psychopath do best.