Yoo Jeong and So Hyeon are not real siblings but have lived together since childhood. So Hyeon is caught by Yoo Jeong spending time at home with her boyfriend. Min Soo saw Yoo Jeong naked in the bathroom. Yoo Jeong is interested in such Min Soo and seduces Min Soo. Min Soo knows that Yoo Jeong and So Hyun are not real sisters and approaches Yoo Jeong right away. So Hyeon finds out and So Hyeon breaks up with Min Soo. Min Soo played with two sisters. (Source: HanCinema)Edit Translation