'Monster Cop' Ma Seok-do investigates an illegal online gambling business led by a former STS Baek and an IT genius CEO Chang. Ma proposes an unexpected alliance to Jang and begins hunting down the criminals.
| Actor | Role |
|---|---|
 Don LeeMa Seok-do | Ma Seok-do |
 Kim Moo-yulBaek Chang-gi | Baek Chang-gi |
 Park Ji-hwanJang I-soo | Jang I-soo |
 Lee Dong-hwiJang Dong-cheol | Jang Dong-cheol |
 Lee Ju-binHan Ji-su | Han Ji-su |
 Lee Beom-sooJang Tae-su | Jang Tae-su |
 Kim Min-jaeKim Man-jae | Kim Man-jae |
 Lee Ji-hoonYang Jong-su | Yang Jong-su |
 Kim Do-gunJung Da-wit | Jung Da-wit |
 Kim Shin-biKang Nam-su | Kang Nam-su |
 Hyun Bong-sikKwon | Kwon |
 Kim Ji-hoonJo Ji-hoon | Jo Ji-hoon |
 Kim Young-woongAhn | Ahn |
| RRyu Ji-hoonLee | Lee |
 Baek Su-hoCho Sung-jae | Cho Sung-jae |
| BBae Jae-wonChoi Yoo-sung | Choi Yoo-sung |
 Ahn Seong-bongJason | Jason |
 Kim Ho-junSalesman | Salesman |
 Jung In-giLi Sang-yong | Li Sang-yong |
 Kwon Il-yongCommissioner General | Commissioner General |
 Park Bo-kyungJin Yeon-ho | Jin Yeon-ho |
 Kim Soo-jinKim Jin-sook | Kim Jin-sook |
 Bae Hae-sunSung-jae's mother | Sung-jae's mother |
 Jo Jin-kyulDetective | Detective |
 Kang Jun-seokDetective | Detective |
 Min Hyo-gyeongHotel staff | Hotel staff |
 Jo Hyun-sikCasino manager | Casino manager |
 Jeong Ji-youngFuneral director | Funeral director |
 Kang Shin-chulInvestor | Investor |
 Jang Tae-minGatekeeper | Gatekeeper |