War with the Guild draws to a close, and conflicts with the Mafia reach a momentary truce. However, an unexpected string of events drags Atsushi and Kunikida into an ill-fated confrontation with characters from their pasts!

With the Armed Detective Agency having narrowly escaped obliteration by the Moby-Dick, the gang enlists help from an old ex-agent and hacker to investigate the bigger organization behind its descent...!