Kogorou Akechi established the Boy Detectives' Club, a private investigation firm that tackles both major and minor cases. During one investigation, Kensuke Hanasaki, one of the younger members, encounters a peculiar amnesiac boy called Yoshio Kobayashi, who has an unusual immortality ability. Impressed by Yoshio's talents, Kensuke invites him to join the Boy Detectives' Club and assist them in solving cases. In return, Kensuke promises to help Yoshio find a way to end his immortality. Initially disinterested, Yoshio reluctantly agrees to Kensuke's proposal. However, over time, he grows to respect and appreciate the group, despite his inherent dislike of people. Trickster: Edogawa Ranpo "Shounen Tanteidan" yori chronicles Akechi and the Boy Detectives' Club's adventures as they solve cases and grapple with a hidden adversary lurking in the darkness known as "The Fiend with Twenty Faces."