When Katie Mitchell brings the violence and horrors of ancient Greek drama to the National Theatre's stage, I rate her as a more original, exciting and imaginative director than any rival working upon the English stage. Yet her latest production, which involves those classic elements of the murder of a much desired woman, a weird love triangle and betrayal, by way of Dostoyevsky's 19th century masterpiece The Idiot, leaves me bemused, confused and deeply unenthused.

... some trace of her - note those pretentious dots - distills the novel's 800 pages into an 80-page script and 90 minute's playing time. This, though, is no miracle of compression. Dostoyevsky's book just about disappears from dramatised view - being shot to pieces and tiny, splintered shards of it hurled on stage in a ceaseless, multi-media rush of video and theatre images, of strange sounds and quartet music. The original narrative vanishes clean away to be replaced by these dislocated fragments.

Those unfamiliar with the novel will find themselves caught in a hopeless struggle to gather what is happening to Ben Whishaw ' s simple-minded, Christ-like Prince Myshkin, who has all his wits about him yet comes both to grief and the attention of Hattie Morahan's inscrutable Nastasya. "I want to find the key to the whole mystery," Whishaw intones mysteriously at the start in that lugubrious voice of his, all intense and monotoned as he presents a wish-list of his life aspirations.

Whishaw, who was a powerful Hamlet four years ago at the age of 23, reappears again and again, but momentarily epileptic, dining, coming under Nastasya's sway, sweating with emotion. We last see him come full circle and delivering the same wish-list.

The image of a woman dead in her wedding dress, with the two men who loved her on either side serves as the inspiration for the evening's mood of doleful reminiscence. Poems by the death-obsessed Emily Dickinson are spliced between scenes, though to what purpose I am unsure.

Dickinson's I Heard A Fly Buzz When I Died might echo the death scene in the novel when the Prince is shown Natasya's corpse and is distracted by the buzzing of a fly.

Not for nothing is ... some trace of her described in the programme as being "inspired by Dostoevsky". For this is Mitchell in her latest, perversely experimental form, drawing theatre and film into a strange marriage as in her extraordinary recreation of Virginia Woolf 's The Waves: the stage is forever packed with scurrying actors whose duty it is to speak voice-overs, to light, arrange and even film the fragmentary scenes that are both acted on stage and relayed, in subtly altered form, on the large video screen above. I found myself once again, as with The Waves, constantly distracted watching the process of arranging each film shot and comparing it with what you see on video.

Miss Mitchell strikes me as being caught in a creative cul de sac. ...some trace of her is not so much about Dostoevsky's novel as the mental pictures, images and feelings it evokes in her mind. It's an aesthete's evening of passionate self-absorption.