Da-hyeon and Hyeon-soo grew up like sisters without their parents, and still live together even after Da-hyeon got married. Sex isn't good between Da-hyeon and her husband, so when her husband is out, she has an affair with a stranger. One day, Hyeon-soo's step-father, Seok-hyeon, goes to his son's house and sees his son's wife's sister there all by herself... 大贤和贤洙像姐妹一样长大，没有父母，即使大贤结婚了，他们仍然生活在一起。达贤和她丈夫之间的性关系不好，所以当她丈夫外出时，她和一个陌生人有了外遇。一天，贤洙的继父Seok Hyeon去他儿子的家，看到他儿子妻子的妹妹独自一人在那里。。。
