Veteran police officer, Bai Qingxiong (Chen Hanwei), forms an agency called Cold Case Investigators (CCI) which aims to crack unsolved cases. Through this agency, he hopes to give a proper closure to family members of the victims. He is a righteous man who is confident that all criminal will not escape the law. The CCI uses unorthodox methods to search for clues which eventually led them to the truth. There are many clashes among the team during the investigation process but sparks also flew among young members, Huang Yuyang (Rebecca Lim), Hong Junyan (Desmond Tan) and Lan Haifeng (Yusuke Fukuchi). The trio soon find themselves entangled in a love triangle. Each time the team manage to solve a case, they are also reminded of their own mystery past. It seems that Qingxiong, Yuyang, and Junyan each have a secret from the past which they are unable to let go of. Eventually, they all decide to work together to investigate their own mystery cases. Can they solve the cases and finally let go of the past?
此剧讲述前CID组长白庆雄(陈汉玮饰)成立“悬案侦探社”CCI,并以私家侦探的身份协助调查二、三十年前无法侦破的悬案,为死者家属查出真相,解答心中疑团。自知一人力量单薄,白庆雄找了前下属黄渝阳(林慧玲饰)、私家侦探洪俊焱(陈泂江饰),以及后来脱离嫌疑的蓝海峰(福地祐介饰)加入阵盟,帮忙查案。
剧中悬案包括发生在新加坡的真实事件,剧中角色将采用现代化的侦察方式以及高科技重新查案,让当年逃过法律制裁的罪犯得到应有的惩罚。