Jack Pro Sir Po is the head of the Forensic Department and is skilled at analysing criminal psychology. He has a unique view on human nature and is familiar with the structure of various firearms. Pro Sir works closely with Senior Pathologist Mandy Chung in a wide range of fields including psychology, anthropology, criminology and forensic science. CID Senior Inspector Ada Ling and Sergeant Wind Lee Chin-fung work together cracking many murder cases. Their relationship goes from good friends 'brothers' to a pair of lovers. With a backbone of 12 cases, the forensic scientists, forensic doctors and the police all work together to accommodate each other to solve these cases.