"Mason & Dixon" is a postmodern historical novel which follows the story of the 18th-century British astronomers and surveyors Charles Mason and Jeremiah Dixon, who are known for the Mason-Dixon line. The novel is written in a complex, digressive style, and it includes numerous sub-plots and a wide range of themes. It explores the scientific, philosophical, and sociopolitical issues of the Enlightenment era, as well as the personal lives and friendship of the two title characters.

A curious and adventurous woman, Miss Pickerell, finds herself accidentally aboard a rocket headed to Mars. Once there, she discovers a range of unique Martian plants and animals, and even stumbles upon a hidden lake. Miss Pickerell uses her scientific knowledge and resourcefulness to solve problems and overcome challenges, ultimately leading to her safe return to Earth.