The novel opens in April, in the Year of Our Risen Lord 1468, as a young priest named Christopher Fairfax rides through the moorland of Wessex. The setting appears medieval: Executed felons hang from gibbets, and the traveler navigates by the setting sun. Only gradually does the reader discover that the calendar has been reset. The year 1468 corresponds not to the Middle Ages but to a civilization rebuilt after the catastrophic collapse of modern technological society. The Church teaches that this collapse was the Apocalypse, divine punishment for elevating science above God.
Fairfax, aged 24, has been sent by Bishop Pole of Exeter to the remote village of Addicott St. George to bury Father Thomas Lacy, who served the parish for 32 years before dying in a 100-foot fall. The corpse is badly disfigured. Agnes Budd, the housekeeper, explains that Lacy left with his trowel and boots and never returned; his body was found near a hilltop site called the Devil's Chair.
During his first night, Fairfax discovers Lacy's study holds heretical material: a complete set of
The Proceedings and Papers of the Society of Antiquaries, whose publications were publicly burned, and a glass cabinet of illegal pre-Apocalypse artifacts including plastic bottles, coins, and one of the ancients' communication devices, a smooth black object bearing the symbol of a bitten apple. Fairfax resolves to say nothing.
The funeral is disrupted when an elderly man shouts that Lacy's death was no accident. Captain John Hancock, a local mill owner, silences him. At the wake, Fairfax meets Hancock and Lady Sarah Durston, a sharp-witted widow. The church clerk reveals that all four parish registers have vanished. A landslide blocks the only road out, trapping Fairfax in the village.
That night, Fairfax reads a volume from Lacy's nightstand containing a letter dated March 2022 from Peter Morgenstern of Imperial College, London. Morgenstern proposes a working party to prepare for civilizational collapse, identifying six catastrophic scenarios including climate change, nuclear exchange, and a general failure of computer networks. He warns that London exists "only six meals away from starvation" (50). The society's president, Dr. Nicholas Shadwell, reports that Morgenstern won a Nobel Prize but none of his work survived. Fairfax is shaken: The Apocalypse may not have been divine punishment but a scientifically explicable disaster.
Agnes's niece Rose, supposedly mute, leads Fairfax through The Piggeries, the village's poorest quarter, to baptize a dying infant. Rose then reveals the missing registers, hidden by Lacy in the stable wall on the day of his death, the same day a stranger visited and Lacy changed the parsonage locks. In the register covering the early 21st century, Fairfax finds a July 2022 marriage entry joining Miss Julia Morgenstern of "Durston Court Lodge" to Mr. Anwar Singh, with her father listed as a university professor.
Fairfax visits Sarah at her ruined estate. She reveals that her late husband excavated ancient glassware near the Devil's Chair over two years before drowning himself. Lacy visited a fortnight before his death, trembled when he touched the glass, and asked where it was found. The answer was the Devil's Chair, where Lacy subsequently fell to his death. Sarah begs Fairfax not to report her involvement, but he refuses. That evening, Hancock tells Fairfax that Sarah has accepted his marriage proposal.
That night, Fairfax considers destroying the register page to protect Sarah but cannot bring himself to cut it: "It would be a sin against history" (116). He recognizes he has absorbed the heresy of antiquarianism. In Shadwell's
Antiquis Anglia, a catalogue of pre-Apocalypse structures, he finds an entry for the Devil's Chair: a concrete cylinder 70 feet tall with no discernible entrance. On Friday, he climbs to the site and discovers human skulls and bones exposed by storms.
Sarah arrives with a handbill advertising a lecture by Shadwell in nearby Axford. Shadwell, branded with the letter H on his forehead, describes the ancients' achievements and demonstrates electricity with homemade apparatus. Sheriffs arrest him. Fairfax and Sarah share their discoveries with Hancock, whose imagination catches fire. He posts 1,000 pounds in bail to free Shadwell and proposes an expedition to the Devil's Chair.
At the site, Shadwell determines the bones were deliberately excavated by Lacy. Trial trenches reveal 10 skeletons, each skull bearing a bullet hole: evidence of a massacre. Over supper, Shadwell concludes the likeliest cause of the Apocalypse was a general failure of computer technology. He traces Morgenstern's movements through inscriptions carved on church walls by desperate survivors, concluding that Morgenstern prepared a refuge at the Devil's Chair.
That night, Fairfax and Sarah sleep together at Hancock's mill house. The captain's sister, Martha Hancock, witnesses Sarah entering Fairfax's room and threatens exposure. The next morning, Fairfax discovers Rose can speak and always could; Agnes confesses Rose is her daughter by Lacy, raised in silence as the condition for remaining in the parsonage. Rose describes the stranger who visited Lacy on the day of his death as a tall man on a mule, matching Oliver Quycke, Shadwell's secretary.
Hancock assembles workers for a full excavation. At depth, the western trench strikes a flat concrete surface: the roof of an underground chamber. Tunneling kills a young worker, and the men refuse to return. Hancock discovers Fairfax and Sarah together. Fairfax confesses: "I took Sarah into my bed last night. I betrayed you under your own roof" (261). Hancock attacks him, nearly strangling him before Sarah breaks a jug over the captain's head.
By Sunday, Quycke has vanished with Shadwell's records and Lacy's books. Fairfax concludes Quycke was Bishop Pole's spy all along: He intercepted a letter Lacy wrote to Shadwell and alerted the bishop, explaining both the pair's delayed arrival and Lacy's panic when Quycke visited. When Shadwell examines the books, he recognizes his own marginalia. The volumes are from his personal library, supposedly burned but secretly preserved by the bishop. Hancock returns with blasting powder and detonates it against the roof.
The explosion opens a fissure into a chamber whose walls bear hundreds of painted handprints recalling prehistoric cave art. On a small altar lies Morgenstern's gold Nobel Prize medal. Before they can open the inner door, Bishop Pole arrives with armed sheriffs and Quycke, revealing he orchestrated the bail so Shadwell would lead them here. Pole insists the site must be sealed. Shadwell confronts him, and Pole admits: "One hides knowledge; one keeps it close" (289). A mudslide strikes, burying Pole, the sheriffs, Hancock, Quycke, and Shadwell.
The collapse throws Fairfax and Sarah through the inner door, which seals behind them. By torchlight, Fairfax reads the painted walls: the Earth's lights going dark, fleeing refugees, burning cities. A portrait of Morgenstern with rays around his head is flanked by faces captioned KIEFER, FISCHER, SINGH, ancestors of present-day village families depicted as saints in St. George's Church. The truth becomes clear: It was not refugees from London who were massacred against the tower but the valley's original inhabitants. Morgenstern's colonists seized the land to survive. A white sarcophagus holds his mummified body surrounded by dozens of dead communication devices arranged like grave goods. A second door will not open without tools. The torch dies. Fairfax lies down beside the injured Sarah as the air fails, the novel ending with their fate unknown.