Steam Detectives

A new criminal has begun operating in the steamy shroud that covers Steam City. The city police cannot keep up with him- he claims that his megamaton has teleport abilities, and it seems to be true. Whenever the cops get close, the machine vanishes in a mysterious fog. Enter the Narutaki Detective Agency. Child sleuth Narutaki hits the set, and quickly gets a hunch regarding the "teleporting" mecha. While the police chase shadows, Narutaki finds the real villain, and the battle is on. After Narutaki's megamaton, Goriki, defeats the enemy machine, the criminal reveals himself- he is Knight Phantom. He speaks of his hatred for Narutaki, and vows to destroy everything he loves. But Narutaki doesn't seem to know who this stranger is.

On his way home, Narutaki sees a young girl kidnapped. He pursues, and eventually frees the girl. When her father comes to get her, they learn that he is a scientist, working on a powerful new power source that could do away with steam energy forever. The assumption is made, that Gina was taken to trade for her father's research. Soon, the girl is taken again, and this time a ransom demand is made- the kidnappers indeed want the meteronite, the crystal energy source her father is developing. A trade off is setup, but at the last minute, Narutaki realizes it is a double cross- Gina's live in tutor is actually the Crimson Scorpion, a thief desiring all beautiful things for herself.

The Machine Baron- The Ultimate Collector. He desires unique and antique machines, old robots, vacuum cleaners, watches; anything of witch there is only one in the world. The villain crashes an antique machine show, but is handily defeated by Narutaki and Goriki. He vows his vengeance, and in order to learn Goriki's weaknesses, disguises himself as a reporter, wanting a story on Narutaki. As time passes, the Machine Baron's desire to destroy Goriki turns into a desire to possess the machine. Unable to bring himself to destroy Goriki when he has the chance, the Machine Baron must finally admit the truth- he has fallen in love with Goriki!

Ling Ling's estranged sister, Lang Lang, shows up at the Narutaki Detective agency unexpectedly. Six months prior, she had joined with Narutaki's rival, Le Bled, and ran away with him. Now, Le Bled has come for a showdown with Narutaki, and Lang Lang's visit is part of his plan. Lang Lang gasses Ling Ling and disguises herself as her sister, then tries to poison Narutaki. He, of course, is too smart for all that. When the plan is foiled, Le Bled appears, and tells Narutaki the only way to save Ling Ling is to defeat him in battle. The fight is joined, and Narutaki does save Ling Ling, but in doing so, Lang Lang and Le Bled are able to escape.

A major convention of world-renowned scientists is coming to Steam City, but there is a problem- someone has been kidnapping the attendees. Narutaki narrows down the list of potential targets to the next two, and goes to warn them. Later, one of them is indeed snatched, but Narutaki and Goriki foil the attempt. Later, at the convention, it is revealed that the other, Dr. Gerhalt Von Halt, is the one behind the kidnappings. He wants the knowledge of the scientists to make his megamaton better than human. He claims his evil identity- Dr. Guilty- and tries to capture the remaining scientists. Narutaki is having none of it, however, and the battle is on. Dr. Guilty's megamaton is strong, however, and Goriki is badly damaged. Just when it seems as though the heroes will be defeated, the scientist Narutaki saved earlier gives Narutaki special bullets; with which the bad guys are at last defeated.

The Crimson Scorpion is on a thieving rampage! She is using disguises fluidly and stealing all sorts of jewelry, but she keeps being disrupted by Narutaki and she ends up getting away with nothing. However, the Crimson Scorpion has set her sights on the most important piece of the Kebecks Royal Jewels – the Blue Teardrop. This necklace is worn around the neck of the reigning female royalty, and the Royal Princess of Kebecks is going to be wearing it during a ceremony when her engagement to the Steam City Prince is announced. Can Narutaki stop this criminal from stealing this important piece of jewelry?