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

Drama tells the story of Ko Dong-Man and Choi Ae-Ra. In their school days, Ko Dong-Man took part in taekwondo. Now, he makes a living by working as a contract employee and also goes after the UFC title. Choi Ae-Ra hoped to become an announcer, but she gave up her dream. Now, she works at the information desk of a department store.

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