Season 3

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.

Dazai Osamu and Nakahara Chuuya are attacked by GSS soldiers in the middle of investigating an explosion caused years ago by Arahabaki.

Nakahara Chuuya and Dazai Osamu reveal the truth behind Arahabaki, Randou, the former Port Mafia boss and Chuuya himself.

Port Mafia executive Ace captures Fyodor, who was behind the destruction of the Moby Dick. Keeping him captured may prove to be more difficult.

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

The Agency is tasked with finding and delivering an important document. A man is hit and killed by a truck. His identity shocks Atsushi.

Louisa reunites with Fitzgerald, but he's not quite the man he used to be.

The leaders of the Port Mafia and the Detective Agency are attacked by an assassin in a mask, leaving both of them ill.

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.

The Detective Agency president is in safe hands for now, but unless he or the Port Mafia boss dies, a full-scale war between the two organizations is inevitable.

Mori Ougai and Fukuzawa Yukichi fight to the death in a desperate bid to save the organizations they lead from falling into a devastating war.

The gifted responsible for the virus is on the run as Nakagawa Atsushi and Akutagawa Ryunosuke chase after him. Meanwhile, the Detective Agency has the Rats' hideout surrounded to try to capture Fyodor Dostoevsky.