Spin ended with the alien Hypotheticals setting a vast Arch over the Indian Ocean. Those who sailed under it found themselves on Equatoria, another planet entirely.
In Axis, a secretive Equatorian community of Fourths - humans who've had their lives extended by illegal Martian technology - raised a boy, Isaac Dvali, to communicate with the Hypotheticals. Interstellar clouds of tiny fragmented Hypothetical nanomachines rained down on Equatoria, an some began to grow. Isaac and Turk Findley, a tough bush pilot an former drifter, were absorbed by a vast concatenation of those growths.
Now, Turk Findley has awakened ten thousand years later, to be collected by the people of Vox - an Equatorian group that's obsessed with the Hypotheticals. The Vox have been waiting for Turn and Isaac for a very long time. Meanwhile, the story of Turk and Isaac among the people of Vox is being scrawled in notebooks by a disturbed man in a hospital on twenty-first-century Earth, in the years following the Spin . . .
It's rare that the concluding volume of a trilogy can easily draw in newcomers unfamiliar with the back-story, but Hugo-winner Wilson does so without breaking a sweat in this traditional science-fiction thriller. In the not-too-distant future, the Sun nears its end as an enigmatic alien race, the Hypotheticals, becomes responsible for enabling humanity's survival. Psychiatrist Sandra Cole works at an intake facility in Houston, assessing the mental states of people taken into custody for evaluation. The drudgery of her job is disrupted when a police officer brings in a seemingly-placid man who writes down things he doesn't understand. His journals present the story of Turk Findley, who returned to the world after 10,000 years, finding himself in the midst of warfare between those who seek direct communication with the aliens, and those who regard such a course as suicidal. Cole's initial view that the writings are simply a pointless joke is shaken when oversight of Cole's case is transferred on a pretext, to another doctor. With relentless momentum Wilson's plot will propel readers along, and the subtle characterizations and sophisticated plotting elevate this to the top ranks of the genre.