Detective Shinjuurou Yuuki—dubbed the "Defeated Detective" by some—solves mysteries around Tokyo in a dystopian future. Shinjuurou's intellect and resourcefulness in cracking cases, notably killings, were aided by his peculiar friend Inga, which resulted in countless mysteries being solved and criminals being apprehended. His companion, on the other hand, appears to have other, more nefarious plans for the persons they apprehend, and the truth about the assistant's identity and motive is kept hidden.