Goo Do-yeon. the daughter of the G company president who has a good personality. is popular, has a lot of money, and is perfect without any gaps. However. Do-yeon's Who in the world is perfect? In the end, Yi-seo sneaks into an officetel to find out Do-yeon's weakness. There, she discovers a completely different step-sister Gu Yi-seo's younger sister is just unlucky and annoying.The side of figure of Doyeon she knew.