Before the novel's opening, "hyper-assistance", a technology allowing travel just shy of the speed of light, is used to move a reclusive space station colony called Rotor from the vicinity of Earth to the newly discovered red dwarf Nemesis.

Back on Earth superluminal flight is perfected, ending Rotor Colony's isolation and opening the galaxy to human exploration.

At the time of the writing, the name Nemesis was given to a hypothetical companion to Earth's Sun that could provide a mechanism for periodic disturbances of comets in the Oort cloud, which would then fall inwards causing mass extinctions.

A few commentators noted that Nemesis contains barely disguised references to the Spacers and their calendar system, the Galactic Empire and even to Hari Seldon which seem to have been deliberately placed for the purpose of later integration into the Foundation universe.

On Kirkus Reviews, the novel is said to be "a medium-future space drama, often quite absorbing despite the absence of a theme or even much of a plot" and a "low-key, oddly likable performance considering that, despite all the complicated maneuvering, nothing much happens: the old Asimov charm keeps the pages turning".

Nemesis turns out to be "in fact nothing more than an average Isaac Asimov novel" with good and bad points summarized as follows: "On the positive side, that means that it has intelligent and thoughtful ideas, a carefully crafted plot, and a well-maintained sense of suspense.

On the negative side, that means that it offers generally perfunctory characterization, an undistinguished prose style, and an excessive emphasis on endless conversation—as in a soap opera, Asimov's characters spend far more time talking about what they are doing than actually doing anything.