Episode 38

The Lone Swordsman and the Famous Detective (孤剣士と名探偵,) is the 38th episode of Bungo Stray Dogs anime series and the first episode of the fourth season. It aired on January 4, 2023.

Summary
Years prior, Fukuzawa is seen looking at newspapers mentioning a bloody ceasefire. He is then seen in a flashback, a bloody blade in hand, with corpses at his feet. On the phone with a man who asks him to join the military police, Fukuzawa refuses, saying that from now on, he will work alone.

When one of Fukuzawa's clients, a company CEO, has been murdered at her office, he heads to the crime scene, where he meets her secretary, who is found checking if every document is still here by putting them on the floor, and the suspect tied up next door. Fukuzawa goes to see the suspect, which appears to be the young skilled assassin, Sakunosuke Oda. An adolescent then arrives to apply for a job, who later claims that the secretary is the real killer after stating his deduction. The young assassin jumps out of the room he was detained in after a brief confrontation with Fukuzawa and kills the secretary before surrendering.

Fukuzawa and the young boy are in a restaurant where the boy introduce himself as Ranpo Edogawa. Upon being asked about his origins, the boy talks about his expulsions at school and work as well as the death of his parents. Fukuzawa allows the boy to come with him to his next mission amidst his initial reluctance so that he can find a new job there.

They arrive at a theater, where Fukuzawa is hired to apprehend a criminal after receiving a death threat signed by an ambiguous "V". They are met by the manager, Egawa, who shows Fukuzawa the note regarding the murder, which Ranpo thinks will happen. To gather information, Fukuzawa and Ranpo question the performers, starting with lead actor Tokio Murakami. They also question the other performers, who think that no murder shall happen.

However, Ranpo believes that the note is a warning rather than a threat for murder. Realizing the boy is special, Fukuzawa asks Ranpo to say what he deduced about him. As the boy uncovers his secretive and painful past with ease, Fukuzawa yells at Ranpo to say no more, accidentially pushing him back. Confirming Ranpo's deducing skills, Fukuzawa asks him to join him on this mission.

The stage play is announced to start shortly, and the public, Ranpo and Fukuzawa are seen entering the theather while Fukuzawa wonders why he decided to team up with Ranpo after swearing he'd work alone.