The main character, Aoi Kusanagi, is a profiling user who works in the Investigation Division 11 of the Metropolitan Police Department . The story begins when a new detective is assigned to the profiling section of the Metropolitan Police Department, where Aoi Kusanagi is. It is a story of Aoi Kusanagi solving a number of bizarre murders using profiling, an investigation method that requires extremely reasoning power to identify the criminal from the psychological state of the criminal and the slightest evidence of the scene.