|A fan build model kit of the INSS MacArthur in the possession of Jerry Pournelle|
Fundamentally, Mote is a book about events, and not people. The Second Empire has arisen, and in the process of establishing it's rule. A daring action leads the dashing noble officer Roderick Blaine into command of the battle cruiser MacArthur. Heavily damaged in this pacification action, it is sent back home, with two important passengers, Lady Sandra young woman from a prominent family conducting field research, and Horace Bury, a merchant suspected of starting a revolt. It is the only starship on the scene as an unknown solar sail spacecraft appears, and disables the unknown ship. Finding out it's from a non Terrestrial race, and this is the first time chance for a First Contact, the MacArthur and its passengers are reassigned, to the first first contact with an alien intelligence.
And what an alien intelligence the Moties turn out to be. A biologically casted species, who must reproduce or die, they are an excellent foil to humanity. They understand the technology of Alderston Drive for interstellar travel, but do not have the Langston Shield that allows human ships to take more damage and even enter the photosphere of a star. Neither party really understands each other is hiding something, like the Imperial Battleship Lenin at the only Alderson point that leaves the system, or the Motie Warrior Caste. The Humanity is just as alien to the Moties psychologically, especially when the MacArthur's engineer meets them. Humanity's lack of specialization drives some of the Moties mad, as well as our reproductive biology. Locked into their star system, the Moties are in an eternal Malthusian Trap.
The characters are not particularly memorable, as they fill roles in the story, and are archetypes for the most part. The big character development moment is for Bury seeing a dead man's space suit filled with Watchmaker Moties causes him to radically change his position, from resentful of the Empire, to knowing it is the only force that defend humanity from the aliens. The final resolution involves a blockade being established at the request of one of the Motie mediators once the truth of the Moties is known. The book ends with Bury getting blackmailed into becoming an agent of the Empire with an officer, Kevin Renner formerly of the MacArthur, reactivated from getting out as his minder.