The group works together to figure out which of the two twins killed the other and how.

A police task force is formed in Seoul to investigate heinous crimes such as serial killers and kidnappers. The four members are the tactless but brilliant leader, the street smart veteran detective, a young and naive data analyst, and a female cop whose instincts are informed by the victim's or perpetrator's homes. The definition of an investigative police procedural. Written by Matthew Weaver

It tells the story of a successful drama writer whose life turns upside down after she discovers that she has a terminal illness and a famous actor who can't act.