An adventure novel that is steeped in science fiction, A Deepness in the Sky combines it all, including love, into this mixed-genre novel.
We learn early on that humanity (or at least the version of future-humanity Vinge focuses on in this novel) has been searching since its conception for aliens beyond their own planet and that now they are about to discover their first glimpse of alien life when they begin to get spiderlike radio transmission in their starfleet search of the planet Arachna.
There are two main groups of people in Vinge's novel: the free trade group of the Qeng Ho (who are generally just merchants and want to trade with the aliens) and the techno-enslaved Emergents (who are basically the villains and want to turn the aliens into slaves). The two groups vie for the aliens. However, they learn quickly that the spider-like aliens, themselves, have a delay. They must wait for their sun to light up again. They have to wait for this every few centuries.
The Emergents (as the more negative of the two human groups) wreaks havoc as the two groups are let loose to convince the aliens for their patronage. Innocent lives are at stake on the planet, and the aliens turn out to have a hand in more than the humans think. In the fray, the Emergents almost succeed in enslaving the entire Qeng Ho (turning many of them into virtual tools). A few brave members of the Qeng Ho break free and help save Arachna from the future-enslavement of the spider aliens planned by the Emergents.
It is important to remember, however, that this is a prequel to other novels in the series; therefore, the Emergents still remain in order to wreak havoc in the future.