The drama follows a group of highly trained profilers in the fictional National Criminal Investigation (NCI) team who track down criminals to solve cases.[5] It begins a year after a crucial error results in a bomb detonating at a hospital, killing several SWAT officers and leaving the NCI team leader Kang Ki-hyung's confidence badly shaken. He returns to work after a long break and is immediately drawn into a serial murder case which requires the NCI team to collaborate with the local police agency's Violent Crimes Unit. They meet the temperamental police officer Kim Hyun-joon, who appears to have a bitter grudge against Ki-hyung.
The team leader and a veteran NCI profiler who has published a book on criminology. Despite his aloof and expressionless exterior he cares deeply for his team, whom he considers to be his second family.[6] He and his wife Seo Hye-won have a son named Han-byul. He is the equivalent of Aaron Hotchner, portrayed by Thomas Gibson.
A second-generation police officer, joins the NCI at the recommendation of Kang Ki-hyung.[6] He was initially a SWAT officer specializing in EOD who had transferred to the Violent Crimes Unit as an investigator after watching one of his subordinates die, when a bomb their team was defusing, exploded. He witnessed his father being murdered by a suspect when he was a child and has little sympathy for criminals.[7] His brash nature and temperament has put him at odds with Ki-hyung and Sun-woo at times but he quickly proves his worth with his attention to detail, sharp instincts and accurate profiling skills.[8] He is the equivalent of Derek Morgan, portrayed by Shemar Moore.
An NCI agent and behavior analyst, her gruff demeanor and exacting mannerisms cause some friction between her and Hyun-joon. She tends to follow protocol and goes by the book, in contrast to Hyun-joon, who tends to rely on his instincts and experience. It is eventually revealed that it is her way of coping with the horrors she regularly witnesses on the job. Like Hyun-joon she is a former police officer. She was only hired to fulfill the female quota and relegated to desk jobs and running errands, which she said spurred her to work even harder to get to where she is now.[6] Her father is a well-known defense lawyer whose clients include members of the business and political elite but Sun-woo remains estranged from him due to the fact that he has bailed out some of the very people she arrested. She is the equivalent of Emily Prentiss, portrayed by Paget Brewster.
She is the NCI's bubbly technical analyst who provides support from her computer. She is the equivalent of Penelope Garcia, portrayed by Kirsten Vangsness.
She is the NCI's media liaison officer and handles press conferences.[9] She has been the guardian of her orphaned niece Ha-eun since the deaths of her sister and brother-in-law. She is the equivalent of Jennifer "JJ" Jareau, portrayed by A.J Cook.
The resident genius and holder of two doctorate degrees, he is a profiler who often follows the team to the field to analyze the crime scene or the suspect's house for further clues. He is socially awkward and has a tendency to spout encyclopedic facts at the wrong time. He is the equivalent of Spencer Reid Ph.D., portrayed by Matthew Gray Gubler.
He is Kang Ki-hyung's superior and has generally been supportive of him and his team. He is the equivalent of Erin Strauss, portrayed by Jayne Atkinson. Kim was busy filming My Father is Strange back and forth so he only made a few appearances.
The series was originally scheduled to be on KBS2TV under Taewon Entertainment and Studio&NEW,[15][16] but was later picked up for broadcast by tvN as its owner CJ E&M's subsidiary Studio Dragon replaced Studio&NEW as co-producer.
This drama airs on a cable channel/pay TV which normally has a relatively smaller audience compared to free-to-air TV/public broadcasters (KBS, SBS, MBC and EBS).
