In the vibrant realm of Cremona, a vigilante known as 'Killer B' roams freely, met with both admiration and pursuit. Armed with extraordinary powers and a keen blade, this enigmatic figure dispenses justice according to his own rules. The elusive Killer B proves too elusive for the Royal Investigation Service (RIS) to capture, prompting the recruitment of the seasoned but idiosyncratic detective Keith Flick, who had withdrawn to the Archives Department after a personal tragedy. As crime surges in Cremona, ranging from covert eliminations of criminals to calculated attacks on prominent figures, it becomes evident that multiple perpetrators are at play. Assisted by his spontaneous partner Lily Hoshina and an unexpected collaboration with Killer B, Keith delves into a web of conspiracies involving clandestine groups, internal subversion, and unethical experiments. As the RIS's involvement takes a dubious turn beyond conventional justice, the narrative unearths the depths of governmental corruption and calls into question the loyalty of trusted companions.