MUSIC DRAMA; The Cenci The Almeida, London

With its extremes of evil and suffering, the story of Beatrice Cenci has a natural appeal for anybody wanting to explore the limits of dramatic experience: Shelley made it the subject of a lengthy tragedy, Artaud made it the starting-point of his Theatre of Cruelty, and now Giorgio Battistelli and Nick Ward, commissioned by Almeida Opera, have used Artaud's version as the basis of an extreme piece of "music drama" - a term that will do as well as any other to describe a project that won't fit any of the usual categories.

Certainly, this isn't a play in the usual sense of the word. With its elided narrative (in brief: Count Cenci murders his sons and rapes his daughter; she kills him and is sentenced to death), and its elusive, declamatory dialogue, The Cenci often feels more like a tract or manifesto. Announcing his decision to begin a career of deliberate devotion to vice, for instance, Beatrice's father (jam for Ian McDiarmid, always happiest playing somebody really unpleasant) comes up with lines like: "I am a force of nature. For me there is no life, no death, no crime, no law... I seek evil, I perform evil, as a principle, compulsively." The actors' voices are picked up and amplified, faded, echoed, distorted - McDiarmid produces an unsettling range of gurglings and rasps; as Beatrice (a stately Anastasia Hille) hangs, her whispers of "Father" rattle through the theatre. (All this is achieved through sadly obtrusive headset microphones, making it look something like Captain Scarlet in Renaissance costume.)

The action is complemented, occasionally drowned, by the extraordinary video trickery projected on to the cross-shaped stage and screens behind and to one side. Candles gutter, flames engulf a doorway, pigs and toads wander in, a feast and then an orgy take place. Lucrezia (Kathryn Pogson), Beatrice's mother, kneels in front of her own image - but, as you watch, her face is shattered, distorted, the pieces shuffled crazily.

With this carnival on stage, Battistelli's music (directed by David Parry) is often the least arresting element of the action. Partly that's the sort of music it is, a pattern of broken gestures and abrupt shifts in texture that finally weave into one fuzzy carpet of sound. But it seems, too, that in trying to integrate the music into the drama, Battistelli has ended up creating background music. Oddly, the programme credits the drama to "Giorgio Battistelli after Antonin Artaud", adding that the text is by Battistelli and Nick Ward and the direction by Nick Ward - which seems like describing Psycho as a "a film by Bernard Herrmann, directed by Alfred Hitchcock". It's especially puzzling to anybody familiar with Ward's recent work as playwright and director - there are clear parallels with his production of The Decameron last year at the Gate, which evinced the same enthusiasm for mythic, visceral stories and an abandonment of the literary in favour of the sensual.

You have probably gathered that it isn't easy to sum up The Cenci - I still don't feel that I have made sense of all the information and ideas it throws at you. It does do what I suppose you require of art - that is, it creates an engrossing and consistent world of its own. Whether it's a world capable of sustaining life is another matter.

Further perfs tonight, 19, 20 July

Robert Hanks