In a world powered by advanced technology, crime and action unfold in the archipelagic nation of Cremona. Koku, the protagonist. Keith, the legendary investigator of the royal police force RIS. A mysterious criminal organization. A wide variety of characters race through the fortified city as it is beset by the serial killer, Killer B, and a chain of crimes in this suspense drama by director Kazuto Nakazawa and Production I.G.