In Steam City, a London‑esque metropolis powered entirely by coal and steam, a mist of vapor often shrouds the streets. Criminals exploit this fog to conceal their schemes, and only a handful of brave individuals venture beyond its haze. Those daring investigators are the Steam Detectives: Narutaki, who wields a versatile convertible pistol; his nurse‑assistant Lingling; and the Megamaton robot Gohliki.