"Prey" is a novel about the wonders and potential hazards of nanotechnology. It is narrated by the protagonist, Jack Forman, who is a 40-year-old stay-at-home husband and father of three. He used to work as a computer programmer at a Silicon Valley company until he was fired for exposing his boss’ corruption. His wife, Julia, works in a top-secret nanotech research lab in the Nevada desert.
When Julia begins to work long hours and behave erratically at home, Jack fears that she is having an affair. Although Julia claims she is working on complex, world-changing nanotechnology, her behavioral changes are such that he does not believe that is the whole story. In addition to becoming more short-tempered with him and their children, she has also started taking more care with her appearance.
When bizarre things start happening to his children and around their home, he begins to fear that something more sinister may be happening. Julia shows Jack a video of the project that she and her team are working on, which involves nanobots being placed inside a human test subject. Later, Jack is asked to go to Julia's company's research lab in the desert to help the team solve software problems they are having with the nanobots. While there, Jack sees a live demonstration of the nanobots in action. The result is so chilling that he realizes there are bigger problems than his fear that Julia may be having an affair.