Kogorou Akechi is the founder of a private investigation firm known as the Boy Detectives' Club. Together, this group takes on cases both great and small. One of their junior members, Kensuke Hanasaki, is out solving a case one day when he happens upon Yoshio Kobayashi, a mysterious amnesiac boy with an inability to die. After seeing his abilities in action, Kensuke offers Yoshio a deal: join the Boy Detectives' Club and help them solve cases, and in exchange he will find a way to help Yoshio die. The apathetic Yoshio accepts this deal begrudgingly, unaware of how different his life will become. Although he does not have much use for people, he gradually begins to acknowledge the group as he spends more time with them while solving cases. Trickster: Edogawa Ranpo "Shounen Tanteidan" yori follows Akechi and the rest of the Boy Detectives' Club as they solve the various cases they are given, all while combating a hidden threat from the shadows—"The Fiend with Twenty Faces." The time period is the 2030s. Before the mysterious detective Kogorou Akechi, the Boys Detective Team is assembled. Their actions have led to the resolution of various small and large incidents. One day, team member Kensuke Hanasaki meets a mysterious boy named Yoshio Kobayashi. Kobayashi, who has an undying body because of an unidentified fog, wishes his own death and refuses contact with others. Hanasaki takes an interest in Kobayashi and invites him to join the Boys Detective Team. The encounter eventually leads them to the connection between the criminal nicknamed the Fiend with Twenty Faces and Kogorou Akechi. The fate of the two begins to move...