It was raining so hard that Mark stayed in the Range Rover, drinking cold espresso straight from the flask and listening to a play on the radio about a widow who compulsively knitted cardigans for her recently-dead husband.

"It took me ages to find this shade of grey. Shale, they call it. It matches his eyes."

"He's dead, Maureen. He's never going to wear it."

"Don't be silly. Nobody dies, so long as you remember what they looked like."

He was thinking about calling it a day when he saw Katie trudging across the field toward him, in her bright red raincoat, with the pointy hood. He let down the window, and the rain spattered icy-cold against his cheek.

"You look drowned!" he called out. "Why don't you pack it in?"

"We've found something really exciting, that's why."

She pulled back her hood. Her curly blonde hair was stuck to her forehead and there was a drip on the end of her nose.

"Where's Nigel?" he asked her.

"He's still there, digging."

"I told him to survey the ditches. What the hell's he digging for?"

"Mark, we think we might have found Shalott."

"What? What are you talking about?"

Katie wiped the rain from her face. "Those ditches aren't ditches, they used to be a stream, and there's an island in the middle. And those lumps we thought were Iron Age sheep-pens, they're stones, all cut and dressed, like the stones for building a wall."

"Oh, I see," said Mark. "And you and Nigel you immediately thought, 'Shalott!'"

"Why not? It's in the right location, isn't it, upstream from Cadbury? And everybody knows that Cadbury was Camelot."

Mark shook his head. "You're hopeless romantics, you and Nigel."

"It's not just the stones, Mark. We've found some kind of metal frame. It's big, and it's very tarnished. Nigel thinks it could be a mirror."

"I get it... island, Camelot, mirror. Must be Shalott!"

"Come and have a look anyway."

Mark checked his watch. "Let's leave it till tomorrow. We can't do anything sensible in this weather.

Katie said, "Please, Mark."

Mark was the boss, and Katie was only a second-year history student, hired for the Easter holidays, but he had already discovered how persistent she could be. "Okay," he said. "If I must."

The widow in the radio-play was still fretting about her latest sweater. "He's not so very keen on raglan sleeves... he thinks they make him look round-shouldered."

"He's dead, Maureen. He probably doesn't have any shoulders."

Katie started back up the hill. Mark climbed down from the Range Rover and trudged through the long grass behind her. He wouldn't have come out here at all, not today, but he was eleven days behind schedule, and the county council were beginning to nag him for his final report.

"Think of it!" Katie called out. "Shalott!"

Mark caught up with her. "Forget it, Katie. It's all stories - especially the Lady of Shalott. A curs�d woman in a castle, dying of unrequited love. Sounds like my ex, come to think of it."

They topped the ridge. Below them lay a misty, waterlogged meadow, crossed diagonally by an ancient ditch. They could see Nigel about a quarter of a mile away, in his fluorescent yellow jacket and his white plastic helmet, digging.

"You see?" Katie persisted. "The island, the river... it's just as Tennyson described it."

"It isn't Shalott, Katie. Even if it were, it's situated slap bang in the middle of the proposed route for the Woolston relief road, which is already three years late and six million pounds over budget. Which means that the county council will have to rethink their entire highways-building plan, and we won't get paid until the whole mess has gone through a full-scale public enquiry, which probably means in fifteen years' time."

"But think of it!" said Katie. "There - where Nigel's digging - that could be island where the castle used to stand, where the Lady of Shalott weaved her tapestries. And that ditch was the river, where she floated down to Camelot in her boat, singing her last sad lament before she died!"

"If any of that is true, sweetheart, then this is the hill where Historic Site Assessment Plc went instantly bankrupt."

"But we'd be famous, wouldn't we?"

"No, we wouldn't. You don't think for one moment that we'd be allowed to dig it up, do you? You and Nigel are still students and I wouldn't recognize a barrow if I tripped over one. Besides, we don't get paid to find sites of outstanding archeological significance, we get paid not to find them. Bronze Age buckle? Shove it in your pocket and rediscover it five miles away, well away from the proposed new supermarket site. An Iron Age sheep pen, fine. We can call in a JCB and have it shifted to the Ancient Britain display at Frome. But not Shalott, Katie. Shalott would sink us."

They struggled down the hill and across the meadow. As they came panting up the side of the ditch, Nigel stood up and took off his helmet. Nigel had tight curly hair, bright red cheeks, and a fresh, simple face like a Hobbit. But Mark hadn't employed him for his Middle Earth looks. He had employed him because he was reading Archeology & Landscape at Essex University, and Mark could boast that Historic Site Assessment plc was "fully staffed by leading experts in their field."

"Nigel! How's it going? Katie tells me you've found Shalott."

"Well - no - Mark! I don't like to jump to hasty conclusions! But these stones, look!

Nigel was circling around the grassy tussocks, flapping his hands. "I've cut back some of the turf, d'you see - and - underneath - well, see?" He had exposed six or seven rectangular stones, the color of well-matured Cheddar cheese. "Bath stone, and look at that jadding... late thirteenth century, I'd say."

"And you think that this is Shalott?"

Nigel looked around the meadow, blinking. "The location suggests it, more than anything else. There was certainly a tower here. You don't use stones five feet thick to build a single-story pigsty, do you? But why would anyone build a tower here, in the middle of a valley?"

"I don't know. You tell me."

"You would only build a tower here as a folly, or to keep somebody imprisoned."

"Like the Lady of Shalott?"

"Well, exactly."

"So, if there was a tower here, where's the rest of it?"

"Oh, robbed out, most likely, over the years. At a very rough estimate it was built just before 1275, and most likely abandoned during the Black Death, around 1340."

"Oh, yes?" Mark was already trying to work out what equipment they were going to need to shift these stones and where they could discreetly dump them.

Nigel pointed to a stone that was still half-buried in grass. There were some deep marks chiselled into it. "Look - you can just make out a cross, and part of a skull, and the letters DSPM. That's an acronym for medieval Latin, meaning 'God save us from the pestilence within these walls.'"

"So whoever lived in this tower... they could have been infected with the Black Death?"

"That's the most obvious assumption, yes. Isn't it exciting?"

Mark looked around. He couldn't decide which he hated more, archeology or rain. "Katie said that you'd found some metal thing."

"Well! Hah! Yes! That's the clincher!"

Nigel strode back to the place where he had been digging. Barely visible in the mud was a length of blackened metal, about a metre-and-a-half long and curved at both ends.

"It's a fireguard, isn't it?" said Mark. Nigel had cleaned a part of it, and he could see that there were flowers embossed on it, and bunches of grapes, and vine-tendrils. In the center of it was a lump that looked like a human face, although it was so encrusted with mud that it was impossible to tell if it was a man or a woman.

Mark peered at it closely. "An old Victorian fireguard, that's all."

"I don't think so," said Nigel. "I think it's the top edge of a mirror. And a thirteenth century mirror, at that."

"Nigel... a mirror, as big as that, in 1275? They didn't have glass mirrors in those days, remember. This would have to be solid silver, or silver-plated, at least."

"Exactly!" said Nigel. "A solid silver mirror - five feet across. And the Lady of Shalott had a mirror, didn't she? Not for looking at herself, but for looking at the world outside, so that she could weave a tapestry of life in Camelot, without having to look at it directly!

"There she weaves by night and day
A magic web with colours gay.
She has heard a whisper say
A curse is on her if she stay
      To look down to Camelot.

"But moving through a mirror clear
That hangs before her all the year,
Shadows of the world appear... "