Seoul, the present day. Ten-year-old Yeon-joo is picked up outside school by a man who says he knows her mother and is then driven to a flat where she is sexually abused. Six hours later, her mother, Yoon Young-nam, reports her disappearance to the police, who say it is too soon to launch a proper investigation. After being found dumped on the street in a suitcase, Yeon-joo is taken to a hospitalby Yoon and recovers; however, Yoon's ex-husband, TV celebrity dentist Dr. Lee, is not happy at the adverse publicity Yoon's action has generated. Yoon eventually persuades a busy detective, Ma, to take an interest in the case; he questions Yeon-joo in hospital but the child reveals little. Later, a female police officer questions her, with more success. Angry at the apparent slowness with which the police are treating the case, Yoon tracks down the child molester herself and confronts him at his flat. After a struggle and chase, the police arrive and take both of them in, though en route the child molester escapes. Yoon decides to take more radical action...
Kim Yeon-hong (Son Ye-jin)appears to have a perfect life. She is beautiful, is married to a charismatic young politician (Kim Joo-hyuk), and her adolescent daughter who used to be a troublesome child is now doing better at school. Her husband, Kim Jong-chan decides to run for office against the powerful incumbent, No Jae-soon (Kim Eui-sung). A few days before the elections, Yeon-hong and Jong-chan's daughter, Kim Min-jin (Shin Ji-hoon) goes missing. At first, they assume she has run off to seek their attention as she had done before. However, Yeon-hong soon finds out that the friend Min-jin said she was going to meet does not exist. Then Yeon-hong learns from the school her daughter attends that she had an eccentric friend named Choi Mi-ok (Kim So-hee [ko]) and they were both bullied by their classmates.