Following the Azure Messenger's bomb threat, the Armed Detective Agency must race to prevent the deaths of hundreds, which would taint the Agency forever. However, Dazai's seemingly distracted by Sasaki Nobuko, the lone survivor of their raid on the abandoned hospital...

On a misty night, Oda Sakunosuke, Dazai Osamu, and Sakaguchi Ango meet as always at their usual bar. For the trio of Port Mafia members, it a night spent in camaraderie like any other, but Ango vanishes that very night. Oda is given a direct order from the Port Mafia boss to find Ango, but...

The leaders of the Agency and the Port Mafia negotiate an alliance. Meanwhile, Dazai and Chuuya face off against Lovecraft.

Atsushi and Akutagawa fail to call off the Moby Dick's descent. They search desperately for other ways to protect Yokohama.

Port Mafia leader Mori Ougai orders a fifteen-year-old Dazai Osamu to investigate the appearance of a certain individual in the Yokohama Settlement area.

The café that the Detective Agency members frequent is attacked by The Park, who are after the Guild’s property.

Tensions between the Detective Agency and the Port Mafia run high as they both scramble to save their own leaders while avoiding an all-out war.