Having grown up together from babies to adults, Oh Sehun and Kim Namjoo never imagined falling in love or getting married, the subject was as good as incest. One day out of the blue Namjoo's feelings suddenly changes, but Sehun's eyes are elsewhere. An incident, however, binds them together. As Namjoo holds on throughout a lonely marriage, will she be able to make him realize his feelings for her?