A large-scale catastrophe is occurring across the planet. Ability users are discovered after the appearance of a mysterious fog, apparently having committed suicide, so the Armed Detective Agency sets out to investigate these mysterious deaths. The case seems to involve an unknown ability user referred to as "Collector," a man who could be the mastermind behind the incident.

Trust and courage are put to the test in order to save the city of Yokohama and ability users across the world from the grip of Collector where the Armed Detective Agency forms an unlikely partnership with the dangerous Port Mafia.

Armed Detective Agency members discuss the most suitable candidate for the second-in-command. Doppo Kunikida is carrying out official errands as planned in his diary as usual. Unexpectedly, a bomb-related incident occurs, challenging the ideals he has always upheld. When weighing one life over hundreds, how will he proceed?

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

Atsushi searches desperately for the control terminal, which he would need to stop the Moby Dick from crashing into Yokohama. He's greeted by Akutagawa and Francis, both of whom have other plans in mind.

Rampo receives an invitation to a detective game from none other than E. A. Poe. He's indifferent at first, until Poe reveals what the reward would be should he win.

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

Atsushi is abducted onto the Moby Dick. Meanwhile, Lovecraft succeeds in capturing Q. Francis F. and the Guild prepare to carry out what they call their "emergency plan."

John S. and Lovecraft hunt down Naomi and Haruno as they flee from town. While Atsushi and Dazai wait for them to arrive at the train station, Dazai notices a shady figure stalking him.

Mori, the leader of the Port Mafia, sends a letter to Margaret M. and Nathaniel H., threatening to destroy them and the ship they are protecting.

Trusting in a life that doesn't require her to kill, Kyouka works her first job at the Armed Detective Agency, but the job ends in a minor disaster. As Atsushi attempts to cheer her up, the unthinkable happens--Kyouka's inactive cell phone rings, and a voice orders Demon Snow to attack Atsushi.

While the leaders of the Port Mafia and the gifted special operations division meet via Ango, Dazai is close to discovering the true significance of the conflict between the three groups. However, in despair, Odasaku's deaf to Dazai's entreaties not to go alone to Mimic's headquarters where Gide awaits...

The Port Mafia's council of five top executives has decreed that Mimic must be annihilated. In the ensuing battle, Odasaku has a fateful encounter with Gide, the leader of Mimic, who makes a cryptic prophecy. Night falls, and the usual bar now awaits Dazai, Odasaku and Ango...

The reason that Odasaku went to a certain Western style restaurant was not just because of the curry. He is having the owner watch over a group of young children who had lost their parents two years ago in the war. Odasaku is trying to track down Ango, and remembers the time they first met. Meanwhile, Dazai manages to catch one of the Mimic soldiers alive in a trap he had set. However, once he gets there, all that is waiting for him is a corpse. Another figure was also waiting for him, his subordinate, Akutagawa Ryuunosuke.

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...