In Roman times, Macey is an ex-soldier with a group of deserters. He has berserker fits (probably epileptic) in which he fights like ten men, using an old stone axe. Escaping from a local tribe, the "Cats" at Rudheath, the soldiers find a stockaded Cat village at Barthomley, which they pillage, killing all the inhabitants except for a young girl, whom they take as a slave. They try to "go tribal", pretending to be members of another tribe, the "Mothers", and settle on Mow Cop. This is a sacred site to the Cats, and the girl is their corn goddess. The Cats mine millstones on Mow Cop, and bring food as offerings. The soldiers think they have engineered a truce, but the girl poisons their food and they have hallucinations, killing themselves. Only Macey is spared, as he never touched the girl, who was raped and impregnated by the others. He and the girl leave together, but first he returns to Barthomley where he buries his talisman, the stone axe head, in the burial mound, asking forgiveness for killing so many villagers. The axe head is later found by Thomas Rowley.
In the time of the English Civil War, Thomas Rowley lives in Barthomley with his wife Margery. They find a stone axe-head buried in an old mound, and call it a "thunderstone", believing it to have been created by lightning striking the ground. They intend to build it into a chimney to guard against future strikes. The village is besieged by Royalist troops, who have fought in Ireland, searching for John Fowler, the village head man who has sided with Parliament. The troops eventually kill Fowler and all the other men of the village. Thomas and Margery are rescued by Thomas Venables, a former villager with the Royalists who once desired Margery. He leads them to a shanty town settlement at Rudheath and tells them to go to his family on Mow Cop once Thomas has recovered from his wounds. They take the thunderstone with them and embed it in the chimney of their new home, where it is found by Tom and Jan.
In the modern day Tom is a teenager living cooped up in a caravan at Rudheath with his parents. He is sustained by his relationship with his girlfriend Jan, who is leaving to become a student nurse in London. To keep their relationship alive they agree to meet regularly in the railway station at Crewe. One day they follow an ancient path from Crewe to the village of Barthomley. Returning next time on bicycles, they go further to Mow Cop, a hill dominated by a folly tower. Here they find a stone axe-head embedded in an old chimney. They decide to make it a symbol of their love. Tom and Jan have been avoiding sex, but Jan reveals that she had an affair while working as an au pair in Germany. After this, Tom becomes unstable. He insists on having sex with Jan, but having done this he becomes even more self-destructive and unbalanced. He tells Jan that he has sold the axe head to a museum, as it was a valuable Neolithic artefact. Their relationship dissolves and they bid a final farewell as Jan's train leaves again for London.
Pieces of the three narratives are alternated in an inconsistent pattern, calling special attention to their similarities beyond the landscape: themes, circumstances, visual descriptions, and even lines of dialogue echo throughout.