Set in a teahouse in Myeong-dong, Seoul right after the end of the Korean War, The 12th Suspect follows the suffocating psychological showdown that takes place between a detective and the 11 suspects who find themselves caught up in a murder case.
| Actor | Role |
|---|---|
 Kim Sang-kyungMaster Sgt. Kim Ki-chae | Master Sgt. Kim Ki-chae |
 Park Sun-youngMadam | Madam |
 Heo Sung-taeNoh Suk-hyon, owner | Noh Suk-hyon, owner |
 Kim Ji-hoonOh Hang-chul, poet | Oh Hang-chul, poet |
 Kim Dong-youngPark In-seong, painter | Park In-seong, painter |
 Jeong Ji-sunWoo Byeong-hong, painter | Woo Byeong-hong, painter |
 Han Ji-anYoo-jung | Yoo-jung |
 Nam Sung-jinBaek Doo-hwan | Baek Doo-hwan |
| DDong Bang-yuShin Yoon-chi, professor | Shin Yoon-chi, professor |
| KKim Hui-sangLee Ki-seob, painter | Lee Ki-seob, painter |
| NNam Yeon-yuNot listed | Not listed |
 Ki Jin-wooNot listed | Not listed |
 Kim Hee-sangLee ki-seob | Lee ki-seob |