Detectives from the present and a detective from the past communicate via walkie-talkie to solve a long-time unsolved case.
Lee Je-hoon
Park Hae-young
Kim Hye-soo
Cha Soo-hyun
Cho Jin-woong
Lee Jae-han
Jang Hyun-sung
Kim Bum-joo
Jung Hae-kyun
Ahn Chi-soo
Kim Won-hae
Kim Gye-chul
Jung Han-bi
Oh Yoon-seo
Lee Yoo-jun
Jung Heon-gi
Kim Min-gue
Hwang Ui-kyung
Kang Chan-hee
Park Sun-woo
Im Hwa-young
Cha Soo-min
Lee Je-hoon
Park Hae-young
Kim Hye-soo
Cha Soo-hyun
Cho Jin-woong
Lee Jae-han
Jang Hyun-sung
Kim Bum-joo
Jung Hae-kyun
Ahn Chi-soo
Kim Won-hae
Kim Gye-chul
Jung Han-bi
Oh Yoon-seo
Lee Yoo-jun
Jung Heon-gi
Kim Min-gue
Hwang Ui-kyung
Kang Chan-hee
Park Sun-woo
Im Hwa-young
Cha Soo-min
Lee Je-hoon
Park Hae-young
Kim Hye-soo
Cha Soo-hyun
Cho Jin-woong
Lee Jae-han
Jang Hyun-sung
Kim Bum-joo
Jung Hae-kyun
Ahn Chi-soo
Kim Won-hae
Kim Gye-chul
Jung Han-bi
Oh Yoon-seo
Lee Yoo-jun
Jung Heon-gi
Kim Min-gue
Hwang Ui-kyung
Kang Chan-hee
Park Sun-woo
Im Hwa-young
Cha Soo-min