A bullied teenager who is locked up at a juvenile detention center due to an unexpected accident, meets a mixed martial arts champion to break through his own limits.
| Actor | Role |
|---|---|
 Kim Min-seokCha Woo-sol | Cha Woo-sol |
 Wi Ha-junJeong Do-hyeon | Jeong Do-hyeon |
 Jung Won-changBae Seok-chan | Bae Seok-chan |
 Lee Jae-kyoonAn Hyun-min | An Hyun-min |
 Bae Myeong-jinLee Won-joon | Lee Won-joon |
 Lee Jung-hyunHan Seong-yong | Han Seong-yong |
 Cha YeobJeong Sang-hyub | Jeong Sang-hyub |
 Shin Min-jaeMin Jong-tae | Min Jong-tae |
 Lee Hyun-wookHyeon Woo-yong | Hyeon Woo-yong |
 Lee Eun-jaeYoon Ji-hee | Yoon Ji-hee |