Purpose of Tutoring: Yeong-tak and Ha-na are stepsiblings who live with the support of their divorced adoptive parents. The two begin taking individual private lessons for their respective careers. Yeong-tak secretly gives his acting teacher Na-ri sleeping pills to covet her body, while Ha-na is busy seducing her physical education teacher Han-cheol. Meanwhile, Na-ri and Han-cheol run into each other at the stepsiblings' house, fall in love at first sight, and seek revenge on the two who offended them.