The entire plot is set on board a spaceship bound for the moons of Jupiter, but it is directly related to the deep crisis and malaise of Earth's social and political system, a "civilization about to go under".

The Psychotechnic Institute, which in earlier centuries subtly "guided" and manipulated the government and sought to prevent such polarization, had become corrupt and discredited and was not restored after the fall of the Humanists.

Its last members degenerated into themselves becoming a fanatic exile faction on Ganymede seeking to seize power by breeding a mindless loyal army of genetically modified troops.

The Institute's place was partly taken by the Order of Planetary Engineers, a secretive "quasi-military, almost religious" organization based at a castle on the edge of Archimedes crater on the Moon.

With its members known as capitalized "Engineers" and bound to contract no formal marriage as long as they are on active duty, it has some characteristics reminiscent of the Free Masons and of the Military Orders of Medieval knights.

Though basically concerned with physical nature and the terraforming of worlds, and officially neutral in politics, the Order maintains an Intelligence arm and an unofficial symbiosis with the Solar Union's Guard.

The terraforming of Venus - a dream of the oppressed earlier colonists depicted in "The Big Rain" - had come true and, freed of a dictatorial regime, the Venusians reverted to a clan society reminiscent of the Scottish Highlands (they habitually wear kilts and glengarries).

The point reiterated in this story, as in much of Anderson's other fiction and non-fiction writings - is that space exploration and colonization is not an unnecessary "luxury" or "waste," but instead essential for humanity's very survival.

The flip side is that - since her speed is greater than the solar escape velocity - should anything prevent "The Thunderbolt" from decelerating, she would go on forever into interstellar space, and all on board would die when supplies run out.

He has considerable intellectual curiosity and knowledge of such abstruse ancient history subjects as Weimar Germany and the struggle between Nazis and Communists - names which mean nothing to most 23rd Century people.

Nothing much happens on board, except for a budding love relationship between Devon and Cleonie Rogers - one of the few people in this period with the money and leisure to engage in space tourism, and one of the few women to keep up an alluring female appearance at a time when the typical Western woman is a "crop-headed, tight-lipped, sad-clad creature".

Ultimately, they intend to launch a surprise attack on Earth, destroying India and other centers of the Kali cult, killing hundreds of millions, and take over power on the rest of the planet.

However, Professor Gomez - leader of the Reformers' group - holes up in the ship's engine room, where it would take the Captain and his crew hours to cut through the thick metal partitions.

The story introduces the theme of protagonists aware that their culture is nearing an inevitable collapse and a "Long Night" and who nevertheless strive, with great courage and sacrifice, to "halt the Norns" - even if for only one more generation.

There is thus no information on how much time the heroic struggle of Captain Banning and his crew bought for the embattled Earth, how the final catastrophic collapse happened, or whose action touched it off - the Western Reformers, their Kali foes, some other factions or all of them together.

Donald Moffitt, in the preface to his 2003 novel Jovian, noted the difficulties which Jupiter's gravity and atmospheric pressure make for Science Fiction writers trying to realistically place humans in that environment.