Joo Yoo-rin is an impostor fluent in Korean, Chinese, and Japanese. Seol Gong Chan is the second-generation heir of a big corporation. Because of his grandfather's illness, he is forced to ask Yoo-rin to be his long-lost cousin so that his grandfather's last wish can be fullfilled. So therefore, they both are bound in a lie that no-one in the family knows the truth. Kim Se-hyeon grew up in a rich family and dreams to become a tennis star with the nickname "Sherapova of Korea". Her charm and intelligence attract many men. She and Yoo-rin engage in cutthroat competitions. Seo Jeong-woo will fall also for Yoo-rin and finally learn to love that special someone.