"Also," said Windle, "it is just possible that I could knot your arms behind you."

"Eeek!"

"He's not an ordinary wolf. You'd better believe it."

"Oook?"

Windle lowered his voice. "And she might not technically be a woman," he added.

The Librarian looked at Ludmilla. His nostrils flared again. His brow wrinkled.

"Oook ?"

"All right, I may have put that rather clumsily. Do let go, there's a good fellow."

The Librarian released his grip very cautiously and sank to the floor, keeping Windle between himself and Lupine.

Windle brushed mortar fragments off the remains of his robe.

"We need to find out," he said, "about the lives of cities. Specifically, I need to know -"

There was a faint jangling noise.

A wire basket rolled nonchalantly around the massive stack of the nearest bookcase. It was full of books. It stopped as soon as it realised that it had been seen and contrived to look as though it had never moved at all.

"The mobile stage," breathed Windle Poons.

The wire basket tried to inch backwards without appearing to move. Lupine growled.

"Is that what One-Man-Bucket was talking about?" said Ludmilla. The trolley vanished. The Librarian grunted, and went after it.

"Oh, yes. Something that would make itself useful," said Windle, suddenly almost maniacally cheerful. ‘That's how it'd work. First, something that you'd want to keep, and put away somewhere. Thousands wouldn't get the right conditions, but that wouldn't matter, because there would be thousands. And then the next stage would be something that would be handy, and get everywhere, and no-one would ever think it had got there by itself. But it's all happening at the wrong time!"

"But how can a city be alive? It's only made up of dead parts!" said Ludmilla.

"So're people. Take it from me. I know. But you are right, I think. This shouldn't be happening. It's all this extra life force. It's... it's tipping the balance. It's turning something that isn't really real into a reality. And it's happening too early, and it's happening too quickly."

"Oh, the poor thing! Look at him!"

Ludmilla rushed across the floor and knelt down by the stricken wolf.

"It went right over his paws, look!"

"And he's probably lost a couple of teeth," said Windle. He helped the Librarian up. There was a red glow in the ape's eyes. It had tried to steal his books.

This was probably the best proof any wizard could require that the trolleys were brainless.

He reached down and wrenched the wheels off the trolley.

"Ole," said Windle.

"Oook?"

"No, Not "with milk"," said Windle.

Lupine was having his head cradled in Ludmilla's lap. He had lost a tooth, and his fur was a mess. He opened one eye and fixed Windle with a conspiratorial yellow stare while his ears were stroked. There's a lucky dog, thought Windle, who's going to push his luck and hold up a paw and whine.

"Right," said Windle. ‘Now, Librarian... you were about to help us, I think."

"Poor brave dog," said Ludmilla.

Lupine raised a paw pathetically, and whined.

Burdened by the screaming form of the Bursar, the other wire basket couldn't get up to the speed of its departed comrade. One wheel also trailed uselessly. It canted recklessly from side to side and nearly fell over as it shot through the gates, moving sideways.

"I can see it clear! I can see it clear!" screamed the Dean.

"Don't! You might hit the Bursar!" bellowed Ridcully. ‘You might damage University property!"

But the Dean couldn't hear for the roar of unaccustomed testosterone. A searing green fireball struck the skewing trolley. The air was filled with flying wheels.

Ridcully took a deep breath.

"You stupid!" he screamed.

The word he uttered was unfamiliar to those wizards who had not had his robust country upbringing and knew nothing of the finer points of animal husbandry. But it plopped into existence a few inches from his face; it was fat, round, black and glossy, with horrible eyebrows. It blew him an insectile raspberry and flew up to join the little swarm of curses.

"What the hell was that?"

A smaller thing flashed into existence by his ear.

Ridcully snatched at his hat.

"Damn!" - the swarm increased by one – "Something just bit me!"

A squadron of newly-hatched Blasteds made a valiant bid for freedom. He swatted at them ineffectually.

"Get away, you b –" he began.

"Don't say it!" said the Senior Wrangler. "Shut up!"

People never told the Archchancellor to shut up. Shutting up was something that happened to other people. He shut up out of shock.

"I mean, every time you swear it comes alive," said the Senior Wrangler hurriedly. "Ghastly little winged things pop out of the air."

"Bloody hellfire!" said the Archchancellor.

Pop. Pop.

The Bursar crawled dazed out of the tangled wreckage of the wire trolley. He found his pointy hat, dusted it off, tried it on, frowned, and took a wheel out of it. His colleagues didn't seem to be paying him much attention.

He heard the Archchancellor say, "But I've always done it! Nothing wrong with a good swear, it keeps the blood flowing. Watch out, Dean, one of the bug -"

"Can't you say something else?" shouted the Senior Wrangler, above the buzz and whine of the swarm.

"Like what?"

"Like...oh...like...darn."

"Darn?"

"Yes, or maybe poot."

"What? You want me to say poot?"

The Bursar crept up to the group. Arguing over petty details at times of dimensional emergency was a familiar wizardly trait.

"Mrs. Whitlow the housekeeper always says "Sugar!" when she drops something," he volunteered.

The Archchancellor turned on him.

"She may say sugar," he growled, "but what she means, is shi-"

The wizards ducked. Ridcully managed to stop himself.

"Oh, darn," he said miserably. The swearwords settled amiably on his hat.

"They like you," said the Dean.

"You're their daddy," said the Lecturer in Recent Runes.

Ridcully scowled. "You b- boys can stop being silly at your Archchancellor's expense and da-jolly well find out what's going on," he said.

The wizards looked expectantly at the air. Nothing appeared.

"You're doing fine," said the Lecturer in Recent Runes. "Keep it up."

"Darn darn darn," said the Archchancellor. "Sugar sugar sugar. Pooty pootity poot. " He shook his head.

"It's no good, it doesn't relieve my feelings one bit."

"It's cleared the air, at any rate," said the Bursar.

They noticed his presence for the first time.

They looked at the remains of the trolley.

"Things zooming around," said Ridcully. "Things coming alive."

They looked up at a suddenly familiar squeaking noise. Two more wheeled baskets rattled across the square outside the gates. One was full of fruit. The other was half full of fruit and half full of small screaming child.

The wizards watched open-mouthed. A stream of people were galloping after the trolleys. Slightly in the lead, elbows scything through the air, a desperate and determined woman pounded past the University gates.

The Archchancellor grabbed a heavy-set man who was lumbering along gamely at the back of the crowd.

"What happened?"

"I was just loading some peaches into that basket thing when it upped and ran away on me!"

"What about the child?"

"Search me. This woman had one of the baskets and she bought some peaches off of me an' then -"

They all turned. A basket rattled out of the mouth of an alleyway, saw them, turned smartly and shot off across the square.

"But why?" said Ridcully.

"They're so handy to put things in, right?" said the man. "I got to get them peaches. You know how they bruise."

"And they're all going in the same direction," said the Lecturer in Recent Runes. "Anyone else notice that?"