6Harold and Echika may have brought their latest case to a close, but the AI developer who facilitated E's campaign against Interpol is nowhere to be found. To ascertain the identity of this enigmatic individual, the pair requests the aid of their friend Bigga, now a consultant with the Electrocrime Investigations Bureau. Yet even her help isn't enough to give them a lead. Meanwhile, a brutally dismembered Amicus is discovered in a public park, and the modus operandi bears an eerie resemblance to the "Nightmare of Petersburg" spree killings in which Harold's mentor was murdered...