Quintus, an Ephesian slave, is in attendance on his master, Sextus Julius Frontinus, the Roman governor of Britain, when Cunicatus, the chief of one of many warring tribes in ‘this hideous island at the edge of the world’, seals a marriage alliance between Frontinus and his daughter, Olwen. She, however, rejects the match, escaping from the camp at dead of night and impulsively asking Quintus to accompany her. Despite having seen a recaptured fugitive in Gaul torn apart between four horses, he agrees to go.

Tim Pears’s Run to the Western Shore follows the pair as they flee through south Wales, hotly pursued by Frontinus’s legionnaires. They encounter a host of wild beasts, including bears, wolves and lynxes, and even wilder people, notably two druids: a priestess who sacrifices an elderly simpleton to ensure a fruitful harvest, and an acolyte who carves a mystic totem pole that predicts the future (wrongly, as it turns out).

Quintus and Olwen are likeable but insubstantial characters. They may have traded conventional gender roles, with Olwen the warrior who fells two of their pursuers while Quintus squeamishly protests at the bloodshed, but they are conventional lovers. On their first night in the open, they make love – in Pears’s admirably even-handed phrase, ‘they possessed each other’. From then on, apart from a momentary hitch when Olwen scorns Quintus as a slave after he challenges her authority, and a brief tussle after she questions his advice not to visit her father, they are of one mind.

Pears wisely makes no attempt to create an archaic idiom, but his simple, uninflected prose isn’t fully successful in integrating ancient and modern. References to a ‘caricature’, ‘monogamous’ beavers and making a ‘snorkel’ sit uneasily in a literary landscape rich in hursts, cromlechs, bwlchs and rindles. Likewise, the druid Munatius’s ritual practices, such as spitting a mouthful of liquid at a bride, are at odds with his Becketttian image of himself as a ‘sack of offal and blood… and a head full of nothing’.

Olwen’s stories of her ancestors, taken from ancient Welsh legends in The Mabinogion, pad out the novel. Its distinction lies less in its characters, ideas or narrative than in its descriptions – notably of birds, including the blackbird with its ear to the ground that ‘looked like it was eavesdropping on some subterranean conversation. Olwen told him it was listening for the sound of worms.’

After the sweeping symphony of his first world war trilogy, this is Pears in minor key.