8-year-old Moonbyul meets her brother's best friend Yongsun( 6 years older) and tells her she will be her wife someday, which seems cute in the teenager's eyes. Minhyuk and Yongsun go through many things together and date and break up several times without ending their friendship.  After living abroad for a long time, Yongsun gets back to Seoul and bumps into the Moon family, She is shocked when she sees 22-year-old Moonbyul and hears from her ex-boyfriend that the girl is the terror

Byul-YI met this guy who has a 2-year-old little boy.  He tells her that he divorced because his wife was an absent mother. They become close to the point the man considers that they are a couple. The baby spends so much time with her that she develops maternal love for him. One day, Byul-YI goes to the kid's school to pick him up and she meets his mother. Both women sit side by side and find out interesting things