In post-war Japan, the nation remains unsettled and crime is as big a problem as ever. Despite his sharp mind and keen deductions, "Defeated Detective" Shinjurou Yuuki frequently loses out to his rival, Rinroku Kaishou, whose information network has previously aided many police investigations. However, in spite of his poor reputation, Shinjurou continues to work on every case he's recruited to with his mysterious assistant Inga. With Inga's power to transform into a being capable of forcing any person to truthfully answer one question put to them, the pair uses everything at their disposal to get to the bottom of each crime and reveal the true culprit – even if the reality of who solved the case never reaches the public...