Yu Ji-ho (M / 35) ➔ Captain (Detective Team Leader) -Green hair- (Husband of Kim Ji-min) Kim Yeon-jae (F / 33) ➔ Lieutenant (Deputy Team Leader) -Yellow hair- Oh Seung-yoon (M / 28) ➔ Sergeant -Brown hair- (Childhood friend of Kim Min-seo) [His father Oh Jeong-taek died in the line of duty during an organized crime investigation in 2011. Seung-yoon was sent for adoption at age 5. His biological mother is Kim Eun-young, 58, Deputy Commissioner. Neither Kim Eun-young nor Oh Seung-yoon knows they are related despite his resemblance to his father. He continues his active duty at the police agency.] Kim Min-seo (F / 28) ➔ Sergeant -Red hair- (Childhood friend of Oh Seung-yoon) Kim Yong-cheol (M / 30) ➔ Corporal Seo Ye-eun (F / 26) ➔ Officer (Childhood friend of Park Tae-seong) Lee Myeong-hak (M / 28) ➔ Sergeant Yu Jin-hee (F / 32) ➔ Lieutenant (Detective Squad Leader) Lee So-young (F / 28) ➔ Sergeant -Blue hair- Kim Hee-cheol (M / 31) ➔ Corporal Lee Yoon-young (F / 31) ➔ Corporal Kang Ho-dong (M / 26) ➔ Officer Kim Tae-won (M / 29) ➔ Sergeant (Husband of Lee Ha-yeon) Park Ye-jin (F / 25) ➔ Officer Lee Su-geun (M / 25) ➔ Officer

Lee Ji-hye (F / 33) ➔ Lieutenant (MIU Squad Leader / Operational Leader) -Orange-brown hair- (Daughter of Deputy Commissioner Lee Da-hee) Kim Hyeon-woo (M / 31) ➔ Corporal -Green hair- (Husband of Seo Seung-hee) Lee Seul-i (F / 29) ➔ Sergeant -Brown hair- Yang Hyeon-jong (M / 32) ➔ Lieutenant (MIU Deputy Squad Leader) -Gold hair- Song Yeon-mi (F / 30) ➔ Corporal -Pink hair- Kang Young-tae (M / 28) ➔ Sergeant Lee Seok-hyeon (M / 30) ➔ Corporal Lee Ha-yeon (F / 29) ➔ Sergeant (Wife of Kim Tae-won) Lee Jae-seong (M / 31) ➔ Corporal Go Eun-min (F / 28) ➔ Sergeant Park Hyeon-gyu (M / 28) ➔ Sergeant Lee Min-ho (M / 29) ➔ Sergeant Yu Hyeon-jin (F / 27) ➔ Sergeant Park Cheol-min (M / 28) ➔ Sergeant Kim Ji-min (F / 32) ➔ Corporal (Wife of Yu Ji-ho) Park Yong-jin (M / 27) ➔ Officer Lee Yeon-hee (F / 26) ➔ Officer Kim Yong-min (M / 26) ➔ Officer Yoon Bo-mi (F / 25) ➔ Officer Choi Tae-hun (M / 25) ➔ Officer

Lee Young-ho (M / 41) ➔ Captain (Cyber Investigation Team Leader) -Green hair- Park Tae-seong (M / 26) ➔ Officer (Childhood friend of Seo Ye-eun) Seo Seung-hee (F / 30) ➔ Corporal -Red hair- (Wife of Kim Hyeon-woo) Lee Tae-min (M / 28) ➔ Sergeant -Yellow hair- Yu Seong-min (M / 29) ➔ Corporal -Purple hair- Kim Jeong-min (M / 25) ➔ Officer Lee Ha-na (F / 25) ➔ Officer Shin Mi-young (F / 29) ➔ Corporal Park Su-jeong (F / 28) ➔ Sergeant -Orange hair- Kim Mi-jin (F / 30) ➔ Lieutenant (Cyber Investigation Squad Leader / Deputy Team Leader)

Kang Dae-hyeop (M / 61) ➔ Senior Superintendent General (Commissioner General / Provincial Commissioner) -Grey-black hair- Commissioner (Remarried to Deputy Commissioner Kim Eun-young; Children 1 son, 2 daughters: Eun-mi F 24, Eun-won M 22, Eun-gyeong 21) (Junior colleague of the late Oh Jeong-taek by 3 years) Kim Eun-young (F / 58) ➔ Superintendent General (Deputy Commissioner) -Brown-khaki hair- Deputy Commissioner (Remarried to Commissioner Kang Dae-hyeop; Children 1 son, 2 daughters: Eun-mi F 24, Eun-won M 22, Eun-gyeong 21) (Senior to Lee Da-hee, former Narcotics Division) [Her husband Oh Jeong-taek died in the line of duty in 2011. She gave up her son Oh Seung-yoon for adoption at age 5. She does not realize that Detective Oh Seung-yoon, 28, is her biological son despite the resemblance. She has remained active in the police agency.] Jeong Jin-woo (M / 55) ➔ Senior Superintendent (Director / Director of Investigation) -Black hair, police cap- Lee Da-hee (F / 53) ➔ Senior Superintendent (Director / Director of Public Safety or Director of Detectives) -Black hair, updo- [Mother of Lee Ji-hye, 33, in MIU] (Junior to Kim Eun-young, former Narcotics Division) Choi Hyeon-bin (M / 49) ➔ Superintendent (Division Chief / Chief of Investigation or Chief of Personnel) -Grey-black hair-