The narrator is a boy of nearly 12 who lives in Larklight, a rambling Victorian house that reaches upwards in all directions from a central cellar where the gravity generator is located. Mechanical servants keep it clean with the aid of alien hoverhogs, who float about inhaling dust and debris. His very proper older sister constantly writes in her secret diary while their father, a naturalist, makes scientific studies of the fish-like creatures that swim in the aether around Larklight, which is floating out in space a bit north of the Moon.
In 1851 the British Empire rules much of the Solar System. Richard Burton -- the 19th century explorer, not the 20th century actor -- is married to a Martian woman. Other aliens come from the moons of Jupiter.
All is going well in the first chapter until Larklight is suddenly attacked by giant 12-legged white spiders, one of them wearing a bowler hat, and our hero and his sister barely escape, only to find themselves in mortal danger on the Moon until they are rescued by the dangerous space pirate Captain Jack Havock, who surprisingly proves to be about the sister’s age. In the course of things they visit various planets and the rings of Saturn, engage in space battles, and even attend an exhibition in Hyde Park.
It’s an intentionally preposterous, reasonably amusing, heavily illustrated parody of 19th century children’s adventure fiction aimed as much at adults as kids and full of reasonably inventive non-stop action. It could be funnier, and it’s as lightweight as a hoverhog, but it has the virtue of being a pretty quick read, and for what it is, it’s a reasonable amount of fun.