Over a decade before the events of the manga series, a chance encounter leads professional bodyguard Yukichi Fukuzawa to begrudgingly take an arrogant boy genius named Ranpo Edogawa under his wing. Their first job brings them to a local theater on high alert after receiving a bizarre death threat — a challenge that will require both Ranpo's brains and Fukuzawa's experience. The aftermath spurs Fukuzawa to establish the Armed Detective Agency, an organization that takes on dangerous jobs even the police won't handle!

It's been roughly one year since Chūya Nakahara joined the Port Mafia, and he's got his sights set on an executive position. But as he makes plans to move up, a man by the name of Paul Verlaine—claiming to be his older brother—appears and vows to assassinate everyone he cares about! Now, Chūya must team up with Adam, a European A.I. investigator, to stop this lunatic before the storm swallows Yokohama once again…

A side story about Akutagawa Ryuunosuke of Port Mafia and Literary Master Gourmet.