In Celyn Jones's sardonic update of "Pwyll, Lord of Dyfed", climate change has brought back the bronze age, without the idealised setting of the medieval version: Starbucks and class-A drugs are still with us, but tribalism and the mounted aristocracy are back, as well as renewable energy. Despite the latter, the lurid urban squalor is amusingly indistinguishable from any present-day British town on a Saturday night.

"Since oil ran out, war had become medieval again." Pwyll may shoot the stag with a Finnish bolt-action rifle, but the result is identical: he upsets Arawn, king of the underworld, and has to swap kingdoms for a year, then kill Arawn's rival Havgan (here, a gangster with a toxic dog-food factory).

The deal also involves sleeping next to Arawn's beautiful wife; in the original, Pwyll refrains from going any further and, thanks to magic, she thinks Pwyll is Arawn, which leads to a delicious moment when the real Arawn finally returns from Dyfed. Celyn Jones retains Pwyll's innocent clumsiness but Pwyll does get the woman. He also gets her "wild sister", Rhiannon, who appears in several tales and is the most affecting character in The Mabinogion: she has her small son stolen from her and has to suffer dreadful punishments, but never loses her dignity and intelligence. The lack of oil means Celyn Jones can retain her mystical association with horses, and he signals her brightness with typical humour: "Rhiannon studied literature and Pwyll was a geography graduate."

When her son Pryderi goes missing, however, she loses "half of her original weight". The Mabinogion never explains who stole him; Celyn Jones blames the Croatian nannies. On his return as a grumpy teenager, the future hero bonds with his father in an exuberantly dangerous bout of surfing. A fitting close, perhaps, when we recall what another Welsh genius, David Jones, said about the ancient tales: "For the Poet or the Artist, 'the past' is much what 'nature' is for him: it is the raw stuff which he uses."