Despite joining the Armed Detective Agency, Nakajima lacks conviction that he'd be of any use. Just as he's about to bid the agency farewell, a bomber takes over the agency with one of the agency employees as his hostage...!

Dazai has a face-off with his ex-partner, Chuuya, as Chuuya attempts to uncover Dazai's true intentions for letting himself get captured. Meanwhile, Atsuhi faces Akutagawa's intense and inexplicable hatred for him, as the ship continues on to the meeting place where he will be handed off in exchange for the bounty on his head...

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.