Betrayed by the boyfriend she trusted, Yuna decides to break her premarital chastity and asks Jeonghoon to have sex with her. Jeonghoon tells this to Yena, Yuna’s younger sister and friend, but Yena’s expression doesn’t look good. Jeonghon has unrequited love for Yuna, the older sister. Yena, in turn, has unrequited love for Jeonghoon. “Why does it have to be my sister and not me? I… I fell in love with you first! So… continue.” The story of how these people, with their own complicated circumstances, overcome their unrequited love in a slightly… or rather, very erotic way.
