 Due to their different approaches to crime solving, Dong-soo clashes with Hwang Shin-hye (Oh Yeon-soo), a profiler who recently returned to Korea after studying overseas.They eventually gain a mutual respect for each other as colleagues, but find themselves in conflict once again when they learn that the gangster they're after is Dong-soo's own brother, Dong-chul.Middle brother Jang Dong-chul (Kim Jae-joong) grew up as a petty thug on the streets, using his fists and wits to survive until he climbs to the top of a crime syndicate.