A series of serial killings is exposed and creates a stir among the public. A killer called "Darker" has been leaving a death notification card after killing scumbags who evaded the law. To counter the provocation of the mysterious killer, the police creates a special investigation team.

• Guo Jingfei
• Li Qian
• Candice Zhao
• Shawn Wei
• Zhu Jie
• Hu Yunhao
• Wang Jing
• Su Beichen