Shin Kaiketsu Jouki Tanteidan(2002)

Shin Kaiketsu Jouki Tanteidan

A Steampunk mystery from the creator of Silent Mobius! In this tale of a past (or future?) that never was, in the age of Steam, masked dandies, dastardly supervillains, and sentient machines stalk a Japanese Gotham by night. Are the sharp wits and quick reflexes of wunderkind detectives Narutaki and pretty nurse Ling Ling enough to thwart evil and unravel the mysteries of this strange world? All steamed up.... When Narutaki meets Ling Ling, a pretty nurse with a dark secret, he gains both a true-blu friend and two new assistants. He'll certainly need all the help he can get when he is forced to do battle with such nefarious villains as the Phantom Knight, the Machine Baron, and Dr. Guilty!

(Source: VIZ Media)

Note: Volumes 1-8 (Chapters 1-58) consists of the original run of Kaiketsu Shoki Tanteidan, with some revisions, before continuing with new material.