On a Christmas Eve, a lifeless body of teenage boy is found. The victim's revenge-driven twin brother checks himself into a juvie to hunt down the suspects.
| Actor | Role |
|---|---|
 JinyoungJoo Il-woo / Joo Wol-woo | Joo Il-woo / Joo Wol-woo |
 Kim Young-minCho Soon-wu | Cho Soon-wu |
 Kim Dong-hwiSon Hwan | Son Hwan |
 Song Geon-heeMoon Ja-hoon | Moon Ja-hoon |
 Heo Dong-wonHan Hee-sang | Han Hee-sang |
| HHwang In-sungGo Bang-cheon | Go Bang-cheon |
 Seo Jin-wonChoi Noo-ri | Choi Noo-ri |
 Kim Jeong-jinBaek Young-jun | Baek Young-jun |
 Yun Yoo-sunJa-hoon's Mother | Ja-hoon's Mother |
 Jung Hae-kyunLawyer | Lawyer |
 Son Byung-wookDemolition Captain | Demolition Captain |
 Jong HoYong-cheol | Yong-cheol |
| PPark Dong-ilDetective | Detective |
 Jin Dae-yeonDisplaced man | Displaced man |
 Kim Ji-minDisplaced wife | Displaced wife |
 Kim In-chulTask Leader | Task Leader |
 Nam Ji-wooJa-hoon's Lawyer | Ja-hoon's Lawyer |
 Im Seo-eunSocial Worker | Social Worker |
| KKim Byeong-gooJo Dae-gyun | Jo Dae-gyun |