JUST BECAUSE SOMETHING IS A METAPHOR DOESN'T MEAN IT CAN'T BE REAL.

Miss Flitworth was aware of a faint echo in the voice, as though the words were being spoken by two people almost, but not quite, in sync.

"How long have you got?"

A MATTER OF HOURS.

"And the scythe?"

I GAVE THE BLACKSMITH STRICT INSTRUCTIONS.

She frowned. "I'm not saying young Simnel's a bad lad, but are you sure he'll do it? It's asking a lot of a man like him to destroy something like that."

I HAD NO CHOICE. THE LITTLE FURNACE HERE ISN'T GOOD ENOUGH.

"It's a wicked sharp scythe."

I FEAR IT MAY NOT BE SHARP ENOUGH.

"And no-one ever tried this on you?"

THERE IS A SAYING: YOU CAN'T TAKE IT WITH YOU?

"Yes."

HOW MANY PEOPLE HAVE SERIOUSLY BELIEVED IT?

"I remember reading once," said Miss Flitworth. "about these heathen kings in the desert somewhere who build huge pyramids and put all sorts of stuff in them. Even boats. Even gels in transparent trousers and a couple of saucepan lids. You can't tell me that's right."

I'VE NEVER BEEN VERY SURE ABOUT WHAT IS RIGHT, said Bill Door. I AM NOT SURE THERE IS SUCH A THING AS RIGHT. OR WRONG. JUST PLACES TO STAND.

"No, right's right and wrong's wrong," said Miss FIitworth. "I was brought up to tell the difference."

BY A CONTRABANDISTOR.

"A what?"

A MOVER OF CONTRABAND.

"There's nothing wrong with smuggling!"

I MERELY POINT OUT THAT SOME PEOPLE THINK OTHERWISE.

"They don't count!"

BUT -

Lightning struck, somewhere on the hill. The thunder-clap rocked the house; a few bricks from the chimney rattled into the grate. Then the windows shook to a fierce wind.

Bill Door strode across the room and threw open the door.

Hailstones the size of hens' eggs bounced off the doorstep and into the kitchen.

OH. DRAMA.

"Oh, hell!"

Miss Flitworth ducked under his arm.

"And where's the wind come from?"

THE SKY? said Bill Door, surprised at the sudden excitement.

"Come on!" She whirled back into the kitchen and scrabbled on the dresser for a candle lantern and some matches.

BUT YOU SAID IT WOULD DRY.

"In a normal storm, yes. In this lot? It's going to be ruined! We'll find it spread all over the hill in the morning!"

She fumbled the candle alight and ran back again.

Bill Door looked out into the storm. Straws whirred past, tumbling on the gale.

RUINED? MY HARVEST? He straightened up. BUGGER THAT.

The hail rumbled on the roof of the smithy.

Ned Simnel pumped the furnace bellows until the heart of the coals was white with the merest hint of yellow.

It had been a good day. The Combination Harvester had worked better than he'd dared to hope; old Peedbury had insisted on keeping it to do another field tomorrow, so it had been left out with a tarpaulin over it, securely tied down. Tomorrow he could teach one of the men to use it, and start work on a new improved model. Success was assured. The future definitely lay ahead.

Then there was the matter of the scythe. He went to the wall where it had been hung. A bit of a mystery, that. Here was the most superb instrument of its kind he'd ever seen. You couldn't even blunt it. Its sharpness extended well beyond its actual edge. And yet he was supposed to destroy it. Where was the sense in that? Ned Simnel was a great believer in sense, of a certain specialised kind.

Maybe Bill Door just wanted to be rid of it, and that was understandable, because even now when it hung innocuously enough from the wall it seemed to radiate sharpness. There was a faint violet corona around the blade, caused by the draughts in the room driving luckless air molecules to their severed death.

Ned Simnel picked it up with great care.

Weird fellow, Bill Door. He'd said he wanted to be sure it was absolutely dead. As if you could kill a thing.

Anyway, how could anyone destroy it? Oh, the handle would burn and the metal would calcine and, if he worked hard enough, eventually there'd be nothing more than a little heap of dust and ashes. That was what the customer wanted.

On the other hand, presumably you could destroy it just by taking the blade off the handle... After all, it wouldn't be a scythe if you did that. It'd just be, well... bits. Certainly, you could make a scythe out of them, but you could probably do that with the dust and ashes if you knew how to do it.

Ned Simnel was quite pleased with this line of argument.

And, after all. Bill Door hadn't even asked for proof that the thing had been, er, killed.

He took sight carefully and then used the scythe to chop the end off the anvil. Uncanny. Total sharpness.

He gave in. It was unfair. You couldn't ask someone like him to destroy something like this. It was a work of art.

It was better than that. It was a work of craft.

He walked across the room to a stack of timber and thrust the scythe well out of the way behind the heap. There was a brief, punctured squeak.

Anyway, it would be all right. He'd give Bill his farthing back in the morning.

The Death of Rats materialised behind the heap in the forge, and trudged to the sad little heap of fur that had been a rat that got in the way of the scythe.

Its ghost was standing beside it, looking apprehensive. It didn't seem very pleased to see him.

"Squeak? Squeak?"

SQUEAK. the Death of Rats explained.

"Squeak?"

SQUEAK, the Death of Rats confirmed.

"[Preen whiskers] [twitch nose]?"

The Death of Rats shook its head.

SQUEAK.

The rat was crestfallen. The Death of Rats laid a bony but not entirely unkind paw on its shoulder.

Squeak.

The rat nodded sadly. It had been a good life in the forge. Ned's housekeeping was almost non-existent, and he was probably the world champion absent-minded-leaver of unfinished sandwiches. It shrugged, and trooped after the small robed figure. It wasn't as if it had any choice.

People were streaming through the streets. Most of them were chasing trolleys. Most of the trolleys were full of whatever people had found a trolley useful to carry - firewood, children, shopping.

And they were no longer dodging, but moving blindly, all in the same direction.

You could stop a trolley by turning it over, when its wheels spun madly and uselessly. The wizards saw a number of enthusiastic individuals trying to smash them, but the trolleys were practically indestructible - they bent but didn't break, and if they had even one wheel left they'd make a valiant attempt to keep going.

"Look at that one!" said the Archchancellor. 'It's got my laundry in it! My actual laundry! Darn that for a lark!"

He pushed his way through the crowds and rammed his staff into the trolley's wheels, toppling it over.

"We can't get a clear shot at anything with all these civilians around," complained the Dean.

"There's hundreds of trolleys!" said the Lecturer in Recent Runes. "It's just like vermine! Get away from me, you - you basket!"

He flailed at an importunate trolley with his staff.

The tide of wheeled baskets was flowing out of the city. The struggling humans gradually dropped out or fell under the wobbling wheels. Only the wizards stayed in the flowing tide, shouting at one another and attacking the silvery swarm with their staves. It wasn't that magic didn't work. It worked quite well.

A good zap could turn a trolley into a thousand intricate little wire puzzles. But what good did that do? A moment later two others would trundle over their stricken sibling.

Around the Dean trolleys were being splashed into metal droplets.

"He's really getting the hang of it, isn't he?" said the Senior Wrangler, as he and the Bursar levered yet another basket on to its back.

"He's certainly saying Yo a lot," said the Bursar.

The Dean himself didn't know when he'd been happier. For sixty years he'd been obeying all the self-regulating rules of wizardry, and suddenly he was having the time of his life. He'd never realised that, deep down inside, what he really wanted to do was make things go splat.

Fire leapt from the tip of his staff. Handles and bits of wire and pathetically spinning wheels tinkled down around him. And what made it even better was that there was no end to the targets. A second wave of trolleys, crammed into a tighter space, was trying to advance over the tops of those still in actual contact with the ground. It wasn't working, but they were trying anyway. And trying desperately, because a third wave was already crunching and smashing its way over the top of them. Except that you couldn't use the word "trying". It suggested some sort of conscious effort, some sort of possibility that there might also be a state of 'not trying'. Something about the relentless movement, the way they crushed one another in their surge, suggested that the wire baskets had as much choice in the matter as water has about flowing downhill.

"Yo!" shouted the Dean. Raw magic smacked into the grinding tangle of metal. It rained wheels.

"Eat hot thaumaturgy, you m-," the Dean began.

"Don't swear! Don't swear!" shouted Ridcully above the noise. He tried to swat a Silly Bugger that was orbiting his hat. "There's no telling what it might turn into!"

"Bother!" screamed the Dean.

"It's no good. We might as well be trying to hold back the sea," said the Senior Wrangler. "I vote we head back to the University and pick up some really tough spells."

"Good idea," said Ridcully. He looked up at the advancing wall of twisted wire. "Any idea how?" he said.

"Yo! Scallywags!" said the Dean. He aimed his staff again. It made a sad little noise that, if it was written down, could only be spelled pfffft. A feeble spark fell off the end and on to the cobbles.

Windle Poons slammed another book shut. The Librarian winced.

"Nothing! Volcanoes, tidal waves, wrath of gods, meddling wizards... I don't want to know how other cities have been killed, I want to know how they ended..."

The Librarian stacked another pile of books on the reading desk. Another plus about being dead, Windle was finding, was an ability with languages. He could see the sense in the words without knowing the actual meaning. Being dead wasn't like falling asleep after all. It was like waking up.

He glanced across the Library to where Lupine was having his paw bandaged.

"Librarian?" he said softly.

"Oook?"

"You've changed species in your time... what would you do if, for the sake of argument, you found a couple of people who... well, suppose there was a wolf that changed into a wolfman at the full moon, and a woman that changed into a wolfwoman at the full moon... you know, approaching the same shape but from opposite directions? And they'd met. What do you tell them? Do you let them sort it out for themselves?"

"Oook, " said the Librarian, instantly.

"It's tempting."

"Oook."

"Mrs. Cake wouldn't like it, though."

"Eeek oook."

"You're right. You could have put it a little less coarsely, but you're right. Everyone has to sort things out for themselves."

He sighed, and turned the page. His eyes widened.

"The city of Kahn Li," he said. "Ever heard of it? What's this book? "Stripfettle's Believe-It-Or-Not Grimoire. " Says here... "little carts... none knew from where they came... of such great use, men were employed to herd them and bring them into the city... of a sudden, like unto a rush of creatures... men followed them and behold, there was a new city outside the walls, a city as of merchants' booths wherein the carts ran"..."

He turned the page.

"It seems to say..."

I still haven't understood it properly, he told himself. One-Man-Bucket thinks we're talking about the breeding of cities. But that doesn't feel right.

A city is alive. Supposing you were a great slow giant, like a Counting Pine, and looked down at a city?

You'd see buildings grow; you'd see attackers driven off; you'd see fires put out. You'd see the city was alive but you wouldn't see people, because they'd move too fast. The life of a city, the thing that drives it, isn't some sort of mysterious force. The life of a city is people.

He turned the pages absently, not really looking...

So we have the cities - big, sedentary creatures, growing from one spot and hardly moving at all for thousands of years. They breed by sending out people to colonise new land. They themselves just lie there. They're alive, but only in the same way that a jelly fish is alive. Or a fairly bright vegetable. After all, we call Ankh-Morpork the Big Wahooni...

And where you get big slow living things, you get small fast things that eat them...

Windle Poons felt the brain cells firing. Connections were made. Thought gushed along new channels. Had he ever really thought properly when he was alive? He doubted it. He'd just been a lot of complicated reactions attached to a lot of nerve endings, with everything from idle rumination about the next meal to random, distracting memories getting between him and real thought.

It'd grow inside the city, where it's warm and protected. And then it'd break out, outside the city, and build... something, not a real city, a false city... that pulls the people, the life, out of the host...

The word we're looking for here is predator.

The Dean stared at his staff in disbelief. He gave it a shake, and aimed it again.

This time the sound would be spelled pfwt.

He looked up. A curling wave of trolleys, rooftop high, was poised to fall on him.

"Oh... shucks," he said, and folded his arms over his head.

Someone grabbed the back of his robe and pulled him away as the trolleys crashed down.

"Come on," said Ridcully. 'If we run we can keep ahead of 'em."

"I'm out of magic! I'm out of magic!" moaned the Dean.

"You'll be out of a lot more if you don't hurry, " said the Archchancellor.

Trying to keep together, bumping into one another, the wizards staggered ahead of the trolleys. Streams of them were surging out of the city and across the fields.

"Know what this reminds me of?" said Ridcully, as they fought their way through.

"Do tell, " muttered the Senior Wrangler.

"Salmon run, " said the Archchancellor.

"What?"

"Not in the Ankh, of course," said Ridcully. "I don't reckon a salmon could get upstream in our river - "

"Unless it walked," said the Senior Wrangler.

"- but I've seen 'em thick as milk in some rivers," said Ridcully. "Fightin' to get ahead. The whole river just a mass of silver."

"Fine, fine," said the Senior Wrangler. 'What'd they do that for?"

"Well... it's all to do with breeding."

"Disgusting. And to think we have to drink water," said the Senior Wrangler.

"Right, we're in the open now, this is where we out-flank 'em," said Ridcully. "We'll just aim for a clear space and - "

"I don't think so," said the Lecturer in Recent Runes.

Every direction was filled with an advancing, grinding, fighting wall of trolleys.

"They're coming to get us! They're coming to get us!" wailed the Bursar. The Dean snatched his staff.

"Hey, that's mine!"

The Dean pushed him away and blew off the wheels of a leading trolley.

"That's my staff!"

The wizards stood back to back in a narrowing ring of metal.

"They're not right for this city, " said the Lecturer in Recent Runes.

"I know what you mean, " said Ridcully. "Alien."

"I suppose no-one's got a flying spell on them today?" the Senior Wrangler enquired.

The Dean took aim again and melted a basket.

"That's my staff you're using, you know."

"Shut up, Bursar," said the Archchancellor. 'And, Dean, you're getting nowhere picking them off one by one like that. OK, lads? We want to do them all as much damage as possible. Remember - wild, uncontrolled bursts..."

The trolleys advanced.

Ow. Ow.

Miss Flitworth staggered through the wet, rattling gloom. Hailstones crunched underfoot. Thunder cannonaded around the sky.

"They sting, don't they," she said.

THEY ECHO.

Bill Door fielded a stook as it was blown past, and stacked it with the others. Miss Flitworth scuttled past him, bent double under a load of corn. The two of them worked steadily, crisscrossing the field in the teeth of the storm to snatch up the harvest before the wind and hail stole it away. Lightning flickered around the sky. It wasn't a normal storm. It was war.

"It's going to pour with rain in a minute. " screamed Miss Flitworth, above the noise. 'We'll never get it down to the barn! Go and fetch a tarpaulin or something! That'll do for tonight!"

Bill Door nodded, and ran through the squelching darkness towards the farm buildings. Lightning was striking so many times around the fields that the air itself was sizzling, and a corona danced along the top of the hedge.

And there was Death.

He saw it looming ahead of him, a crouched skeletal shape poised to spring, its robe flapping and rattling behind it in the wind.

Tightness gripped him, trying to force him to run while at the same time rooting him to the spot. It invaded his mind and froze there, blocking all thought save for the innermost, tiny voice which said, quite calmly: SO THlS IS TERROR.

Then Death vanished as the lightning glow faded, reappeared as a tree was struck on the next hill.

Then the quiet, internal voice added: BUT WHY DOESN'T IT MOVE?

Bill Door let himself inch forward slightly. There was no response from the hunched thing.

Then it dawned on him that the thing on the other side of the hedge was only a robed assemblage of ribs and femurs and vertebrae if viewed from one point of view but, if looked at slightly differently, was equally just a complexity of sparging arms and reciprocating levers that had been covered by a tarpaulin which was now blowing off.

The Combination Harvester was in front of him.

Bill Door grinned horribly. Un-Bill Door thoughts rose up in his mind. He stepped forward.

The wall of trolleys surrounded the wizards.

The last flare from a staff melted a hole, which was instantly filled up by more trolleys.

Ridcully turned to his fellow wizards. They were red in the face, their robes were torn, and several over-enthusiastic shots had resulted in singed beards and burnt hats.

"Hasn't anyone got any more spells on them?" he said.

They thought feverishly.

"I think I can remember one," said the Bursar hesitantly.

"Go on, man. Anything's worth trying at a time like this."

The Bursar stretched out a hand. He shut his eyes. He muttered a few syllables under his breath.

There was a brief flicker of octarine light and -

"Oh, " said the Archchancellor. 'And that's all of it?"

" "Eringyas' Surprising Bouquet"," said the Bursar, bright eyed and twitching. "I don't know why, but it's one I've always been able to do. Just a knack, I suppose."

Ridcully eyed the huge bunch of flowers now gripped in the Bursar's fist.

"But not, I venture to point out, entirely useful at this time," he added.

The Bursar looked at the approaching walls and his smile faded.

"I suppose not," he said.

"Anyone else got any ideas?" said Ridcully.

There was no reply.

"Nice roses, though," said the Dean.

"That was quick," said Miss Flitworth, when Bill Door arrived at the pile of stooks dragging a tarpaulin behind him.

YES, WASN'T IT, he mumbled noncommittally, as she helped him drag it over the stack and weigh it down with stones. The wind caught at it and tried to drag it out of his hands; it might as well have tried to blow a mountain over.

Rain swept over the fields, among shreds of mist that shimmered with blue electric energies.

"Never known a night like it," Miss Flitworth said.

There was another crack of thunder. Sheet lightning fluttered around the horizon.

Miss Flitworth clutched Bill Door's arm.

"Isn't that... a figure on the hill?" she said. 'Thought I saw a...shape."

NO, IT'S MERELY A MECHANICAL CONTRIVANCE.

There was another flash.

"On a horse?" said Miss Flitworth.

A third sheet seared across the sky. And this time there was no doubt about it. There was a mounted figure on the nearest hilltop. Hooded. Holding a scythe as proudly as a lance.

POSING. Bill Door turned towards Miss Flitworth. POSING. I NEVER DID ANYTHING LIKE THAT. WHY DO ANYTHING LIKE THAT? WHAT PURPOSE DOES IT SERVE?

He opened his palm. The gold timer appeared.

"How much longer have you got?"

PERHAPS AN HOUR. PERHAPS MINUTES.

"Come on, then!"

Bill Door remained where he was, looking at the timer.

"I said, come on!"

IT WON'T WORK. I WAS WRONG TO THINK THAT IT WOULD. BUT IT WON'T. THERE ARE SOME THINGS THAT YOU CANNOT ESCAPE. YOU CANNOT LIVE FOREVER.

"Why not?"

Bill Door looked shocked. WHAT DO YOU MEAN?

"Why can't you live for ever?"

I DON'T KNOW. COSMIC WISDOM?

"What does cosmic wisdom know about it? Now, will you come on?"

The figure on the hill hadn't moved.

The rain had turned the dust into a fine mud. They slithered down the slope and hurried across the yard and into the house.

I SHOULD HAVE PREPARED MORE. I HAD PLANS -

"But there was the harvest."

YES.

"Is there any way we can barricade the doors or something?"

DO YOU KNOW WHAT YOU'RE SAYING?

"Well, think of something! Didn't anything ever work against you?"

NO, said Bill Door with a tiny touch of pride.

Miss Flitworth peered out of the window, and then flung herself dramatically against the wall on one side of it.

"He's gone!"

IT, said Bill Door. IT WON'T BE A HE YET.

"It's gone. It could be anywhere."

IT CAN COME THROUGH THE WALL.

She darted forward, and then glared at him.

VERY WELL. FETCH THE CHILD. I THINK WE SHOULD LEAVE HERE. A thought struck him. He brightened up a little bit.

WE DO HAVE SOME TIME. WHAT IS THE HOUR?

"I don't know. You go around stopping the clocks the whole time."

BUT IT IS NOT YET MIDNIGHT?

"I shouldn't think it's more than a quarter past eleven."

THEN WE HAVE THREE-QUARTERS OF AN HOUR.

"How can you be sure?"

BECAUSE OF DRAMA, MISS FLITWORTH. THE KIND OF DEATH WHO POSES AGAINST THE SKYLINE AND GETS LIT UP BY LIGHTNING FLASHES, said Bill Door, disapprovingly, DOESN'T TURN UP AT FIVE AND-TWENTY PAST ELEVEN IF HE CAN POSSIBLY TURN UP AT MIDNIGHT.

She nodded, white-faced, and disappeared upstairs. After a minute or two she returned, with Sal wrapped up in a blanket.

"Still fast asleep," she said.

THAT'S NOT SLEEP.

The rain had stopped, but the storm still marched around the hills. The air sizzled, still seemed oven-hot.

Bill Door led the way past the henhouse, where Cyril and his elderly harem were crouched back in the darkness, all trying to occupy the same few inches of perch.

There was a pale green glow hovering around the farmhouse chimney.

"We call that Mother Carey's Fire," said Miss Flitworth. "It's an omen."

AN OMEN OF WHAT?

"What? Oh, don't ask me. Just an omen, I suppose. Just basic omenery. Where are we going?"

INTO THE TOWN.

"To be near the scythe?"

YES.

He disappeared into the barn. After a while he came out leading Binky, saddled and harnessed. He mounted up, then leaned down and pulled both her and the sleeping child on to the horse in front of him.

IF I'M WRONG, he added, THIS HORSE WILL TAKE YOU WHEREVER YOU WANT TO GO.

"I shan't want to go anywhere except back home!"

WHEREVER.

Binky broke into a trot as they turned on to the road to the town. Wind blew the leaves off the trees, which tumbled past them and on up the road. The occasional flash of lightning still hissed across the sky.

Miss Flitworth looked at the hill beyond the farm.

I KNOW.

"- it's there again -"