It presents a fictionalized account of the collaboration between Charles Mason and Jeremiah Dixon in their astronomical and surveying exploits in the Dutch Cape Colony, Saint Helena, Great Britain and along the Mason-Dixon line in British North America on the eve of the Revolutionary War in the United States.

The novel opens during the winter of 1786 as the Reverend, by request from his nephews, embarks on his first story set in America, which begins with his recollection of the first meeting of Charles Mason and Jeremiah Dixon as told to him by the two men.

Episode 6 Ordered once more to Bencoolen, despite its being currently occupied by French troops, Mason, Dixon, and the Reverend find themselves aboard the newly repaired Seahorse, now escorted by a second frigate as far as the open sea.

Episode 7 The Seahorse arrives for a stay in Cape Town where Mason and Dixon are greeted by a member of the local constabulary who warns them against spreading political notions amongst the colony's slaves.

Episode 16 Mason tells Dixon how he first met his wife Rebekah at a cheese-rolling festival in Randwick, but his narrative is briefly interrupted by the Reverend's audience who protest contradictions with historical records.

Episode 19 The death of Bradley is the topic of discussion at a local pub called "The George" and provides a segue into talk about the 1752 conversion of England to the Gregorian calendar and the resulting "missing" eleven days.

The discussion grows heated and scientific by turns and introduces a new territory to the book with the revelation that Macclesfield recruited a cadre of "Asiatic Pygmies" to colonize the missing time and preserve temporal flow.

After a brief interruption from the Reverend Cherrycoke's audience discussing the magic and commercial prospects in America, Dixon is introduced to Father Christopher Maire, a Jesuit priest and acquaintance of Emerson.

Episode 23 At Emerson's local pub, with Maire disguising his Jesuit connections under civilian clothes, the trio discusses a variety of topics including China, Feng Shui, ley lines, and a network of ancient tunnels that lies beneath County Durham.

Maire's admission that he has spent time in Italy heightens suspicion of his identity but he quickly deflects it by offering to cook the first pizza in England, a ghastly concoction of tough bread, ketchup brought back from the Cape by Dixon, and stilton cheese.

While journeying down the Thames River, where he will meet Mason to sign the contract that will send them to America, Dixon and the boat's crew encounter a heavy fog that mystically, but briefly, transports them to the hostile shores of Delaware.

The discussion ranges between Judaism, Chief Pontiac, the demarcation of western lines by the French and British, and the telluric plates left by one Celeron de Bienville in his efforts to claim territory.

Dixon, in yet another coffee house, falls into conversation with Dolly over Mason's and Molly's shared melancholic personalities, and a series of puzzling measurements that seem to suggest Pennsylvania is moving by degrees each year.

Episode 36 During a nor'easter, Mason and Dixon seek refuge in an inn called "The India Queen" and discover the presence of Reverend Cherrycoke, who now bears a commission as chaplain of the expedition.

Decidedly nonplussed by this revelation, the duo welcome his company and proceed to spend the night at the inn drinking, talking, and observing the variety of clientele brought in by the storm while they enjoy the food of its exiled French chef, Armand Allegre.

In their efforts to close off the Tangent line they discover some anomalies in previous measurements as well as legal inconsistencies that leave a small "Wedge" of ambiguous territory neither in Maryland or Pennsylvania, creating yet another of the novel's uncharted alternate domains.

The chapter closes with the discovery of their subterfuge, Squire Haligast warning that the party will soon encounter "China-men," and the delivery of a package from Maskelyne telling of geographical interferences with measurements that forces Mason to recall the windward side of St. Helena.

Episode 51 An opening that features the two main characters playing practical jokes on one another is followed by a night of heavy rain and fearful talk of Indian attack and The Black Dog, the latest fearsome-fantastic rumored to stalk the wilderness and a possible stand-in for Cerberus.

The scenery and passing of the seasons moves their thoughts to the past, causing Mason and Dixon to wonder on the relation between this defeat and the treatment of British weavers rebelling against wage reduction by James Wolfe, hero of the Abraham Plains.

Episode 53 An apparent captivity narrative begins, telling of how an unidentified colonial American woman is taken from her farmstead by nonviolent Indians across the Susquehanna River and north to a Jesuit college in Quebec.

Included are the possibilities that they are being used by Jesuits to rid the earth of Feng-shui (the line being a terrible example of it, according to Zhang), or guided, perhaps magnetically, to secret ore deposits cherished by the Indians and required for the manufacture of ammunition.

Dimdown, similarly transformed, re-enters and Dixon marvels at the breadth of the movement and the possibility of insurrection, discussing grievances against the crown before engaging in a friendly debate over the quality of American versus British beer.

Episode 64 Zhang tells the story of Hsi and Ho, ancient Chinese astronomers, who are forced to flee when they fail to predict an eclipse, embarrassing their master the emperor who should have intimate knowledge of all "divine" occurrences.

They escape via flying apparatus, bickering all the while, and crash into the estate of a wealthy lord with a "harem" of nubile daughters, who hires them so he can have foreknowledge of celestial events and gain an advantage in business and war.

Episode 65 The surveyors run the line, while Zhang questions the effect of the lost 11 days on the Chinese calendar, and whether it has created inconsistencies and error among all historical time-keeping, leading to discourse on the correct dating of the birth of Christ.

The Indians then regale them with tales of an area to the west filled with giant produce and containing a marijuana plant so large its branches support settlements, perhaps as a coded effort to sell the surveyors some of that latter substance.

Episode 70 The surveyors finish the line, and deciding to take their chances, leave the party and cross the "Warrior-Path" in the dead of night to ride to the river, all the while suffering from various ailments and delusions, as well as paranoia they will encounter a similar fate to Edward Braddock.

Episode 72 The surveyors complete the meridian line and venture to Baltimore, where Dixon interferes with a slave-driver, first berating him in a tavern before beating him in the street, liberating his slaves, and escaping with Mason, who admires him for his action.

Mason's second wife Mary prays for her husband and returns to England with their younger children, while Doctor Isaac and William, Rebekah's sons, stay in America and see out their father's final days.

Club, Harold Bloom said, "I don't know what I would choose if I had to select a single work of sublime fiction from the last century ... it would probably be Mason & Dixon, if it were a full-scale book, or if it were a short novel it would probably be The Crying of Lot 49.