A killer called "Darker" has been leaving a death notification card after killing scumbags who evaded the law. Police reacted by forming a task force with the elite personnels from each field to capture the vigilante. But in reality, what each department did was dumping their best but most eccentric members to the task force. There is the high IQ but low EQ criminalist Luo Fei, the ill-mannered profiler Mu Jian Yun, the inflexible captain Han Hao, the cowardly crime lab specialist Yin Jian, the gothic loving forensic pathologist Liang Yin, the hacker Zeng Ri Hua, and the volatile combat specialist Xiong Yuan. With each murder, the task force uncovers the crimes the victims had committed, at the same time, gets closer to finding the mysterious vigilante.