“Anyway,” said the leader of the merchants, “it seems to be your problem again, my lord.”

Five minutes later the Patrician was striding the length of the Oblong Office, fuming.

“They were laughing at me,” said the Patrician. “I could tell!”

“Did you suggest a working party?” said Wonse.

“Of course I did! It didn't do the trick this time. You know, I really am inclined to increase the reward money.”

“I don't think that would work, my lord. Any proficient monster slayer knows the rate for the job.”

“Ha! Half the kingdom,” muttered the Patrician.

“And your daughter's hand in marriage,” said Wonse.

“I suppose an aunt isn't acceptable?” the Patrician said hopefully.

“Tradition demands a daughter, my lord.”

The Patrician nodded gloomily.

“Perhaps we can buy it off,” he said aloud. “Are dragons intelligent?”

“I believe the word traditionally is 'cunning', my lord,” said Wonse. “I understand they have a liking for gold.”

“Really? What do they spend it on?”

“They sleep on it, my lord.”

“What, do you mean in a mattress?”

“No, my lord. On it. ”

The Patrician turned this fact over in his mind. “Don't they find it rather knobbly?” he said.

“So I would imagine, sir. I don't suppose anyone has ever asked.”

“Hmm. Can they talk?”

“They're apparently good at it, my lord.”

“Ah. Interesting.”

The Patrician was thinking: if it can talk, it can negotiate. If it can negotiate, then I have it by the short-by the small scales, or whatever it is they have.

“And they are said to be silver tongued,” said Wonse. The Patrician leaned back in his chair.

“Only silver?” he said.

There was the sound of muted voices in the passageway outside and Vimes was ushered in.

“Ah, Captain,” said the Patrician, “what progress?”

“I'm sorry, my lord?” said Vimes, as the rain dripped off his cape.

“Towards apprehending this dragon,” said the Patrician firmly.

“The wading bird?” said Vimes.

“You know very well what I mean,” said Vetinari sharply.

“Investigations are in hand,” said Vimes automatically.

The Patrician snorted. “All you have to do is find its lair,” he said. “Once you have the lair, you have the dragon. That's obvious. Half the city seems to be looking for it.”

“If there is a lair,” said Vimes.

Wonse looked up sharply.

“Why do you say that?”

“We are considering a number of possibilities,” said Vimes woodenly.

“If it has no lair, where does it spend its days?” said the Patrician.

“Inquiries are being pursued,” said Vimes.

“Then pursue them with alacrity. And find the lair,” said the Patrician sourly.

“Yes, sir. Permission to leave, sir?”

“Very well. But I shall expect progress by tonight, do you understand?”

Now why did I wonder if it has a lair? Vimes thought, as he stepped out into the daylight and the crowded square. Because it didn't look real, that's why. If it isn't real, it doesn't need to do anything we expect. How can it walk out of an alley it didn't go into?

Once you've ruled out the impossible then whatever is left, however improbable, must be the truth. The problem lay in working out what was impossible, of course. That was the trick, all right.

There was also the curious incident of the orangutan in the night-time . . .

By day the Library buzzed with activity. Vimes moved through it diffidently. Strictly speaking, he could go anywhere in the city, but the University had always held that it fell under thaumaturgical law and he felt it wouldn't be wise to make the kind of enemies where you were lucky to end up the same temperature, let alone the same shape.

He found the Librarian hunched over his desk. The ape gave him an expectant look.

“Haven't found it yet. Sorry,” said Vimes. “Enquiries are continuing. But there is a little help you can give me.”

“Oook?”

“Well, this is a magical library, right? I mean, these books are sort of intelligent, isn't that so? So I've been thinking: I bet if I got in here at night, they'd soon kick up a fuss. Because they don't know me. But if they did know me, they'd probably not mind. So whoever took the book would have to be a wizard, wouldn't they? Or someone who works for the University, at any rate.”

The Librarian glanced from side to side, then grasped Vimes's hand and led him into the seclusion of a couple of bookshelves. Only then did he nod his head.

“Someone they know?”

A shrug, and then another nod.

“That's why you told us, is it?”

“Oook.”

“And not the University Council?”

“Oook.”

“Any idea who it is?”

The Librarian shrugged, a decidedly expressive gesture for a body which was basically a sack between a pair of shoulderblades.

“Well, it's something. Let me know if any other strange things happen, won't you?” Vimes looked up at the banks of shelves. ' 'Stranger than usual, I mean.''

“Oook.”

“Thank you. It's a pleasure to meet a citizen who regards it as their duty to assist the Watch.”

The Librarian gave him a banana.

Vimes felt curiously elated as he stepped out into the city's throbbing streets again. He was definitely detecting things. They were little bits of things, like a jigsaw. No one of them made any real sense, but they all hinted at a bigger picture. All he needed to do was find a corner, or a bit of an edge . . .

He was pretty certain it wasn't a wizard, whatever the Librarian might think. Not a proper, paid-up wizard. This sort of thing wasn't their style.

And there was, of course, this business about the lair. The most sensible course would be to wait and see if the dragon turned up tonight, and try and see where. That meant a high place. Was there some way of detecting dragons themselves? He'd had a look at Cut-me-own-Throat Dibbler's dragon detectors, which consisted solely of a piece of wood on a metal stick. When the stick was burned through, you'd found your dragon. Like a lot of Cut-me-own-Throat's devices, it was completely efficient in its own special way while at the same time being totally useless.

There had to be a better way of finding the thing than waiting until your fingers were burned off.

The setting sun spread out on the horizon like a lightly-poached egg.

The rooftops of Ankh-Morpork sprouted a fine array of gargoyles even in normal times, but now they were alive with as ghastly an array of faces as ever were seen outside a woodcut about the evils of gin-drinking among the non-woodcut-buying classes. Many of the faces were attached to bodies holding a fearsome array of homely weapons that had been handed down from generation to generation for centuries, often with some force.

From his perch on the roof of the Watch House Vimes could see the wizards lining the rooftops of the University, and the gangs of opportunist hoard-researchers waiting in the streets, shovels at the ready. If the dragon really did have a bed somewhere in the city, then it would be sleeping on the floor tomorrow.

From somewhere below came the cry of Cut-me-own-Throat Dibbler, or one of his colleagues, selling hot sausages. Vimes felt a sudden surge of civic pride. There had to be something right about a citizenry which, when faced with catastrophe, thought about selling sausages to the participants.

The city waited. A few stars came out.

Colon, Nobby and Carrot were also on the roof. Colon was sulking because Vimes had forbidden him to use his bow and arrow.

These weren't encouraged in the city, since the heft and throw of a longbow's arrow could send it through an innocent bystander a hundred yards away rather than the innocent bystander at whom it was aimed.

“That's right,” said Carrot, “the Projectile Weapons (Civic Safety) Act, 1634.”

“Don't you keep on quoting all that sort of stuff,” snapped Colon. “We don't have any of them laws any more! That's all old stuff! It's all more wossname now. Pragmatic.”

“Law or no law,” said Vimes, “I say put it away.”

“But Captain, I was a dab hand at this!” protested Colon. “Anyway,” he added peevishly, “a lot of other people have got them.”

That was true enough. Neighbouring rooftops bristled like hedgehogs. If the wretched thing turned up, it was going to think it was flying through solid wood with slots in it. You could almost feel sorry for it.

“I said put it away,” said Vimes. “I'm not having my guards shooting citizens. So put it away.”

“That's very true,” said Carrot. “We're here to protect and to serve, aren't we, Captain.”

Vimes gave him a sidelong look. “Er,” he said. “Yeah. Yes. That's right.”

On the roof of her house on the hill, Lady Ramkin adjusted a rather inadequate folding chair on the roof, arranged the telescope, coffee flask and sandwiches on the parapet in front of her, and settled down to wait. She had a notebook on her knee.

Half an hour went by. Hails of arrows greeted a passing cloud, several unfortunate bats, and the rising moon.

“Bugger this for a game of soldiers,” said Nobby, eventually. “It's been scared off.”

Sgt Colon lowered his pike. “Looks like it,” he conceded.

“And it's getting chilly up here,” said Carrot. He politely nudged Captain Vimes, who was slumped against the chimney, staring moodily into space.

“Maybe we ought to be getting down, sir?” he said. “Lots of people are.”

“Hmm?” said Vimes, without moving his head.

“Could be coming on to rain, too,” said Carrot.

Vimes said nothing. For some minutes he had been watching the Tower of Art, which was the centre of Unseen University and reputedly the oldest building hi the city. It was certainly the tallest. Time, weather and indifferent repairs had given it a gnarled appearance, like a tree that has seen too many thunderstorms.

He was trying to remember its shape. As in the case with many things that are totally familiar, he hadn't really looked at it for years. Now he was trying to convince himself that the forest of little turrets and crenellations at its top looked just the same tonight as they had done yesterday.

It was giving him some difficulty.

Without taking his eyes off it, he grabbed Sgt Colon's shoulder and gently pointed him in the right direction.

He said, “Can you see anything odd about the top of the tower?”

Colon stared up for a while, and then laughed nervously. “Well, it looks like there's a dragon sitting on it, doesn't it?”

“Yes. That's what I thought.”

“Only, only, only when you sort of look properly, you can see it's just made up out of shadows and clumps of ivy and that. I mean, if you half-close one eye, it looks like two old women and a wheelbarrow.”

Vimes tried this. “Nope,” he said. “It still looks like a dragon. A huge one. Sort of hunched up, and looking down. Look, you can see its wings folded up.”