Observer No. 13

The Tokyo Metropolitan Police Department's Scientific Investigation Research Institute (Kesouyan) has an unlisted "Special Countermeasures Room" that specializes in handling "zero-certificate crimes" with perfect closed-loop logic chains and no traces on the scene. Chief Kudo Kiyoshi, a genius who was ostracized by the police because he suffered from "emotional apathy", never believed in intuition and only believed in the law of material exchange. When he was dealing with a seemingly simple "secret room suicide case," he discovered that a microchip left in the deceased's stomach actually pointed to a logical maze that spanned twenty years. In this maze, the villain is not killing people, but performing a perfect "artistic composition". "There are no perfect crimes in the world, only loopholes that have not yet been observed."