It tells the story of a kidnapping case in which Lee Jung-hyun plays the police officer "Xiao En" who replaces the parents of the abducted child, disguises herself as a member of the abduction case and engages in a thorough psychological warfare with the abductor. Moon Jung-hee plays "Hui Zhen" who is related to the kidnapping case, and Kyung Hee-yeon plays "Yeon-joo", the mother of the kidnapped child.