Rarely can so primitive a way of life have been evoked with such lavish technical sophistication. Throughout this 100-minute opera a film runs on two screens, mixing archive 1920s footage of the St Kilda community (living on gale-swept islands 40 miles from the Outer Hebrides) with a specially made docudrama that not only depicts the natural wonders of these gaunt volcanic stacks — the teeming bird colonies, towering cliffs and tumultuous Atlantic breakers — but also speculates on what tragedy might have forced the remaining 36 islanders to quit for ever in 1930.

On stage the actors and singers offer a stylised, highly choreographed and sometimes rather oblique version of the same story: about two young lovers, the last hope of the dwindling community, whose happiness is cut short when the boy plunges to his death while on one of the vital bird-netting expeditions. Above the cast, three acrobats evoke the perils of these expeditions with heartstopping stunts on ropes and high ledges — mirroring their extraordinary aerial ballet on the vertical cliff faces seen on the film.

Meanwhile, a five-strong band (directed by Jean-Paul Dessy, who wrote the music with David P. Graham) underpins a score that is itself many-layered and multicultural. There are electronic effects and avant-garde dissonances, but also recordings of natural sounds, baleful choral chants, haunting unaccompanied Gaelic songs (delivered beautifully by Alyth McCormack) and, near the end, an anguished cello solo that seems to conjure up the indomitable mystery of these isles.

At first the complexity of Thierry Poquet’s French-Belgian-Scottish co-production seems disconcertingly at odds with the rugged subject matter. And I’m not sure, even in cultured Edinburgh, that presenting a text (Iain Finlay Macleod) that’s mostly in French and Gaelic without surtitles is the best way to endear new opera to the public. But soon the story’s ghostly power quickly gripped me at least. Final performance is tonight.

I warmed up for the show, spiritually speaking, by catching the Lewis Psalm Singers at Greyfriars Kirk. A dozen islanders of all ages, they produce a marvellous, almost anarchic sound: a sort of staggered unison, but with every voice simultaneously embellishing the Gaelic psalm tunes with cacophonic variants that seem to come straight from the ancestral soul. The place was packed. A world tour must be on the cards.

Festival box office: 0131-473 2000