A serial killer is caught for his seventh murder. A cop tries to solve the first six cases with the killer's help, but starts to suspect that he has ulterior motives. Based on a true story.
| Actor | Role |
|---|---|
 Kim Yoon-seokKim Hyeong-min | Kim Hyeong-min |
 Ju Ji-hoonKang Tae-oh | Kang Tae-oh |
 Moon Jeong-heeKim Soo-min | Kim Soo-min |
 Jin Sun-kyuDetective Jo | Detective Jo |
 Jeong Jong-junChief of Crime Department | Chief of Crime Department |
 Heo JinJi-hee's Grandmother | Ji-hee's Grandmother |
 Kim Joong-kiLawyer | Lawyer |
 Kim Young-woongJeong-bong | Jeong-bong |
 Jeong Gi-seopDetective Han | Detective Han |
 Kim Mi-hwaHair Salon Manager | Hair Salon Manager |
 Lee Bong-ryeonKang Sook-ja | Kang Sook-ja |
 Jeon Kuk-hwanHyeong-min's Father | Hyeong-min's Father |
 Kim Jong-sooCaptain Ma-soo | Captain Ma-soo |
 Bae Hae-sunPark Mi-yeong | Park Mi-yeong |
 Won Hyun-junKim Wook-cheol | Kim Wook-cheol |
 Park Jin-youngJudge | Judge |
 Ju Jin-moSong Kyeong-soo | Song Kyeong-soo |
 Ko Chang-seokDiving Captain Jam-soo | Diving Captain Jam-soo |
 Lee Yoo-junPresident Park | President Park |
 Kwon So-hyunOh Ji-hee | Oh Ji-hee |
 Jeong Taek-hyeonYoung Kang Tae-oh | Young Kang Tae-oh |
 Kim Mi-kyungNoodle Restaurant Owner | Noodle Restaurant Owner |
 Park Sung-hyunDetective | Detective |
 Shim So-youngWoman | Woman |