Inspector Koo

Lee Young-ae

Koo Kyung-yi· 12 ep

Kim Hye-jun

Song Yi-kyung / "K"· 12 ep

Kim Hae-sook

Director Yong· 12 ep

Kwak Sun-young

Na Je-hui· 12 ep

Baek Sung-chul

Santa· 12 ep

Cho Hyun-chul

Oh Gyeong-su· 12 ep

Lee Hong-nae

An Geon-uk· 12 ep

Jeong Seok-yong

Mr. Kim· 11 ep

Jeong Jong-jun

Je-hui's father· 9 ep

Park Kang-seop

Lee Dae-ho· 8 ep

Bae Hae-seon

Jung Jeong-yeon· 6 ep

Choi Young-jun

Jang Seong-u· 6 ep

Park Ji-bin

Heo Hyeon-tae· 6 ep

Choi Dae-chul

Heo Seong-tae· 6 ep

Kim Kang-hyun

Kim Min-gyu· 5 ep

Park Ye-yeong

Yoon Jae-yeong· 4 ep

Kim Soo-ro

Ko Dam· 4 ep

Kim Ki-cheon

Gardener· 2 ep

Jeon Seok-chan

[Detective]· 2 ep

Ahn Ryeo-jin

Escort (Eps 1, 2)· 2 ep

Park Ye-ni

Yi-kyung's mother· 1 ep

Jeong Yoon-hee

Na Je-Hui's Colleague (Eps 8)· 1 ep

Han Seung-Yun

[Policeman]· 1 ep