In Trickster: Edogawa Ranpo "Shounen Tanteidan" yori, Kogorou Akechi leads the Boy Detectives' Club, a team dedicated to solving mysteries big and small. When junior member Kensuke Hanasaki encounters Yoshio Kobayashi, a peculiar boy with an immortal nature and amnesia, he proposes a deal: join the club to unravel cases in exchange for finding a way for Yoshio to end his eternal existence. Reluctantly, Yoshio agrees, finding himself drawn into a world of investigations and unexpected camaraderie. While initially detached, Yoshio gradually warms up to his new companions as they tackle cases and face off against the enigmatic "The Fiend with Twenty Faces" lurking in the shadows.