Morganton's Mayor Elias Smith is understandably worried and turns to the federal government for assistance. Chief Inspector John Strock is sent from Washington to get to the bottom of things. Or, rather, the top. Of the Eyrie, that is. He, Smith and some guides make a failed attempt to scale the pinnacle and have to return empty handed. What is up there? Strock returns to Washington and receives a threatening letter, posted from Morganton, warning him to stay away from the Eyrie. The writer is identified only by the initials "M.O.W."
Strock's superior Mr. Ward assigns him to another, seemingly unrelated case. It seems someone calling himself the "Master of the World" has been terrorizing the country using a "tri-phibian" vehicle called the Terror, which can, at will, go on land as a car, in the sea as a submarine and in the air as an airship, transforming effortlessly between all three. It's going to be Strock's job to discover who is doing this and why. He quickly makes the connection between this vehicle and the incident at the Eyrie, realizing it was the Terror's commander who threatened him.
An attempt to arrest the crew of the Terror near Lake Erie ends with one of Strock's men wounded by gunfire, and Strock himself tangled in the mooring line and dragged after the escaping Terror when its crew flees the authorities. Strock blacks out and thinks he has drowned... only to later awaken safe and sound in a cabin on board, having been rescued by the criminals for some unknown reason. But now he is a prisoner on board the mysterious vessel! Who is the Terror's mysterious inventor and commander, and what dire plans does he have for the captive policeman?
Master of the World shows examples of the following tropes:
- Aliens in Cardiff: The eerie phenomena occur mainly in North Carolina, Wisconsin, Kansas, and the Great Lakes. (Of course, those locales would seem a good deal more exotic to your typical French reader, and thus to Verne himself.)
- The Big Race: The Terror appears during one in Wisconsin.
- By-the-Book Cop: Our hero, John Strock.
- Cool Boat: The Terror, a streamlined, super-fast motorboat camouflaged so as to be almost invisible on the waves. Press a button and it becomes a submarine.
- Cool Car: The Terror, an armored car that can go twice as fast as any other vehicle on the road.
- Cool Plane: The Terror, an ornithopter with retractable wings. Seeing a pattern here?
- Da Chief: Mr. Ward, Strock's boss.
- Darker and Edgier: The novel's often held up as an example of how Verne, in his later years, became more and more pessimistic about humanity's use of science and technology.
- The Dragon: John Turner, another returning character from Robur the Conqueror.
- Driving Question: What the heck's going on at the Great Eyrie?
- Lead Police Detective: Strock, of course.
- Mad Scientist: The Master of the World is a brilliant inventor. Pity he's also a monomaniac...
- Old Retainer: Strock's housekeeper has been in the family for years.
- One-Steve Limit: Averted. Not only is Strock's first name John, but there is also Robur's right-hand man John Turner as well as one of Strock's fellow police officers, John Hart. However since all of the characters are on a Last-Name Basis, it never becomes confusing which John is which.
- The Reveal: When we discover that the Master of the World is none other than Robur the Conqueror.
- Sky Pirate: The Master of the World himself, when the Terror is in flight mode.
- Stealth Sequel: We don't find out until very late indeed that the book's actually a sequel to a previous Verne novel, Robur the Conqueror.
- Submarine Pirates: The crew of the Terror.
- Sudden Name Change: If you remember Tom Turner from the Verne novel Robur the Conqueror, you'll wonder why he's referred to as John Turner here.
- Swiss-Army Weapon: The Terror's mutability is why it's seen as so much of a threat.
- Transforming Mecha: The Terror, a flying machine that can also become a boat, a sub, or an armored car, is probably the Ur-Example. Sadly, Verne being the stickler for realism that he was, the world had to wait another half-century for Japanese creators to come up with the now-ubiquitous humanoid robot mode.
- The Unreveal: Strock learns a whole lot less about the Terror and its inventor than he had hoped.
- U.S. Marshal: Strock, a federal law officer sent out on farflung missions, fulfills this type of role. (Verne doesn't actually use the word "marshal," and is vague on the details of how American law enforcement works, but the idea is there.)