Bungo Stray Dogs season 4

Several years before the beginning of the series, a former military man named Yukichi Fukuzawa investigates a scene of crime involving murder. Initially, he suspects that the young hitman Sakunosuke Oda as the culprit but the researcher investigating the area turns out to be the culprit and is killed by Oda. Fukuzawa meets the young intelligent detective Ranpo Edogawa who has surprised him with his highly developed intelligence when solving cases and agrees to help him find a job. As Ranpo deduces from Fukuzawa's appearance that he is a former war soldier who killed several people in a previous conflict, Fukuzawa is stressed by remembering his past but still decides to help Ranpo with a job. In the next case, Ranpo investigates death threats sent towards an actor from a play.

In the play, Fukuzawa notices that Ranpo is tired of being the only intelligent person so he convinces him that he possesses a supernatural talent that makes him standout within society and that he should only use his skills for the jobs. In the play, the leading actor appearently dies and Ranpo asks Fukuzawa to calm the viewers. Ranpo reveals a suspicious man to be a possible criminal but ends up saying that there was no death as the leading actor faked his death. In the aftermath, Ranpo takes a liking to Fukuzawa.

Apparently en route to the police station, Mitamura praises Ranpo's deduction skills and Fukuzawa's prowess in solving the recent case. However, Ranpo claims that Mitamura still doubts him possessing an ability, so he offers to answer the cop's questions until he runs out of queries to prove that he is truly gifted. As a start, Ranpo correctly deduces that they are not heading to the police station, which Mitamura dismisses can be easily observed. Ranpo then urges him to ask anything related to the recent incident, to which Mitamura asks how the suited man restrained in the theater was captured. The detective reveals that someone abducted the man using a rug and organic solvent, whom Mitamura guesses must be the playwright Kurahashi, but Ranpo states that the latter must have been already killed even before the performance. He also points out that the entire project is an elaborate ploy all to abduct the suited man, afterwards slyly calling out Mitamura for reeking of organic solvent.

One month after the Cannibalism incident, Fukuzawa and the Armed Detective Agency are awarded by the Ministry of Justice for ensuring the safety and protecting Yokohama during the fall of Moby Dick. Meanwhile, Kunikida trains Atsushi in physical combat.

Port Mafia boss Mori wants Yosano to join them in exchange for assisting the Detective Agency through their crisis. Yosano reveals why she would rather not.^[6]