THEATRE: Hafod Ely Hospital, Cardiff

According to the notes written to accompany this performance, Thomas Johnes was an 18th-century Welsh landowner - perhaps an equivalent to Wiltshire's William Beckford or Norfolk's Thomas Coke - who attempted to transform his Cardiganshire estate, Hafod, into a picturesque utopia. His daughter, Marianne, grew up there and became a gifted naturalist before falling ill with a wasting disease, while Johnes himself was eventually bankrupted by the enterprise. In 1807, Hafod was destroyed by a fire. Marianne died in 1811, followed by Johnes himself in 1813.

Performed in two disused psychiatric wards of Ely Hospital in Cardiff, where the company had developed the work over a period of 13 weeks, Brith Gof's Hafod offered, according to project director Clifford McLucas: "No Grand Unified Theory of Hafod, Thomas Johnes or, indeed, the 18th century. Instead you will witness a portrayal where architecture, historical reading and theatre come together to create a real, fractured and alien world."

After gathering in the car park of the hospital, we were led into the performance space where the 30 or so of us were then sent into either the upstairs or downstairs wards. Here, amid the institutional green painted walls and lino floors, we sat on rows of metal chairs, facing television screens showing white noise, and the still figures of actors wearing underwear, with bandages wrapped around their heads, Invisible Man-style.

Another formally dressed Invisible Man arrived to switch on the telly and the action began, with the screens showing live-relays of pictures from either our own level or the one above. As a metaphor for the impossibility of understanding the world of the past, the business of the two separate levels worked very well. Slivers of the story slipped tantalisingly into view - Johnes in a periwig and silk stockings, Marianne writhing in Laban- movement madness - and then receded.

A few carefully-worked images spluttered briefly: Marianne's pregnant belly as a shopping-bag full of rice that rained a cascade of basmati on to the lino; Johnes's progress across the floor accompanied by a white mist of blown baby-powder (shades of the film Ridicule). The striking moment when Johnes confessed his carnal love for Marianne as she pressed her anguished face into the screen of the telly was effective, but the slow drip, drip, drip of the performance could be wearingly monotonous.

Before the final movement, there was a kind of sub-Brechtian unmasking scene in which the artifices of the show were catalogued (the periwig was made in Korea and borrowed from HTV). As the actor's monologue reached the words "and of course, my arse", one had to smile, for the arse in question had been much in view. After a model of Hafod was burned and a blurry montage of scenes from a Hayley Mills film had appeared on telly for some time, the performance ended, and we all trooped back out to the car park.

It was strange alright; it was alien; but - and I know it's reading against the text - there's a great story in there somewhere. While one had hoped for bold, crystalline images, what one got was often - like the pictures on the telly - decidedly low-resolution.