Today, as criminal methods become more and more sophisticated, the technical requirements for criminal police investigation skills and forensic analysis are relatively higher. In order to respond to the scientific spirit of handling cases, each prefecture police station in Japan has a scientific research institute, referred to as "Kesouyan". The business content of "Kesouyan" includes not only the identification of hair, blood, voiceprints, and DNA, but also lie detection and facial restoration. Although they are not on the front line of arresting criminals, they are important figures who help clarify the truth and find murderers. This drama allows everyone to take a deep look at the mysterious world of Kesouyan through the case handling process of Mariko, a spicy female forensic doctor with a unique personality who is active in Kesouyan. The protagonist Mariko is a forensic researcher at the Kyoto Prefectural Police and the Scientific Research Institute. She has rich professional knowledge at work and is also unusually sensitive to criminal incidents, so she can often successfully solve strange cases. However, in her private life, she is a divorced single woman. Due to her stubbornness, pride and easily angered personality, she is constantly in conflict with her colleagues.