“Not with your lucky arrow,” said Nobby.

' “That's right. But, just out of interest, how far down is it, d'you think?” said Colon.

“About thirty feet, I'd say. Give or take.”

“Thirty feet.” Colon nodded slowly. “That's what I'd reckon. And it's deep, is it?”

“Very deep, I've heard.”

“I'll take your word for it. It looks pretty mucky. I'd hate to have to jump in it.”

Carrot slapped him cheerfully on the back, nearly pushing him over, and said, “What's up, Sarge? Do you want to live for ever?”

“Dunno. Ask me again in five hundred years.”

“It's a good job we've got your lucky arrow, then!” said Carrot.

“Hmm?” said Colon, who seemed to be in a miserable daydream world of his own.

“I mean, it's a good job we've got a last desperate million-to-one chance to rely on, or we'd really be in trouble!” “Oh, yes,” said Nobby sadly. “Lucky old us.”

The Patrician lay back. A couple of rats dragged a cushion under his head.

“Things are rather bad outside, I gather,” he said.

“Yes,” said Vimes bitterly. “You're right. You're the safest man in the city.”

He wedged another knife in a crack in the stones and tested his weight carefully, while Lord Vetinari looked on with interest. He'd managed to get six feet off the floor and up to a level with the grille.

Now he started to hack at the mortar around the bars.

...

The Patrician watched him for a while, and then took a book off the little shelf beside him. Since the rats couldn't read the library he'd been able to assemble was a little baroque, but he was not a man to ignore fresh knowledge. He found his bookmark in the pages of Lacemaking Through the Ages, and read a few pages.

After a while he found it necessary to brush a few crumbs of mortar off the book, and looked up.

“Are you achieving success?” he inquired politely.

Vimes gritted his teeth and hacked away. Outside the little grille was a grubby courtyard, barely lighter than the cell. There was a midden in one corner, but currently it looked very attractive. More attractive than the dungeon, at any rate. An honest midden was preferable to the way Ankh-Morpork was going these days. It was probably allegorical, or something.

He stabbed, stabbed, stabbed. The knife blade twanged and shook in his hand.

...

The Librarian scratched his armpits thoughtfully. He was facing problems of his own.

He had come here full of rage against book thieves and that rage still burned. But the seditious thought had occurred to him that, although crimes against books were the worst kind of crimes, revenge ought, perhaps, to be postponed.

It occurred to him that, while of course what humans chose to do to one another was all one to him, there were certain activities that should be curtailed in case the perpetrators got over-confident and started doing things like that to books, too.

The Librarian stared at his badge again, and gave it a gentle nibble in the optimistic hope that it had become edible. No doubt about it, he had a Duty to the captain.

The captain had always been kind to him. And the captain had a badge, too.

Yes.

There were times when an ape had to do what a man had to do ...

The orangutan threw a complex salute and swung away into the darkness.

...

The sun rose higher, rolling through the mists and stale smoke like a lost balloon.

The rank sat in the shade of a chimney stack, waiting and killing time in their various ways. Nobby was thoughtfully probing the contents of a nostril, Carrot was writing a letter home, and Sergeant Colon was worrying.

After a while he shifted his weight uneasily and said, “I’ve fought of a problem,”

“Wassat, Sarge?” said Carrot.

Sergeant Colon looked wretched. “Weeell, what if it's not a million-to-one chance?” he said.

Nobby stared at him.

“What d'you mean?” he said. “Well, all right, last desperate million-to-one chances always work, right, no problem, but. . . well, it's pretty wossname, specific. I mean, isn't it?” “You tell me,” said Nobby. “What if it's just a thousand-to-one chance?” said Colon agonisedly. “What?”

“Anyone ever heard of a thousand-to-one shot coming up?”

Carrot looked up. “Don't be daft, Sergeant,” he said. “No-one ever saw a thousand-to-one chance come up. The odds against it are-” his lips moved- “millions to one.” “Yeah. Millions,” agreed Nobby. “So it'd only work if it's your actual million-to-one chance,” said the sergeant. “I suppose that's right,” said Nobby. “So 999,943-to-one, for example-” Colon began. Carrot shook his head. “Wouldn't have a hope. No-one ever said, 'It's a 999,943-to-one chance but it might just work.' ”

They stared out across the city in the silence of ferocious mental calculation.

“We could have a real problem here,” said Colon eventually.

Carrot started to scribble furiously. When questioned, he explained at length about how you found the surface area of a dragon and then tried to estimate the chances of an arrow hitting any one spot. “Aimed, mind,” said Sergeant Colon. “I aim. ” Nobby coughed.

“In that case it's got to be a lot less than a million-to-one chance,” said Carrot. “It could be a hundred-to-one. If the dragon's flying slowly and it's a big spot, it could be practically a certainty.” Colon's lips shaped themselves around the phrase,

It's a certainty but it might just work. He shook his head. “Nah,” he said.

“So what we've got to do, then,” said Nobby slowly, “is adjust the odds ...”

...

Now there was a shallow hole in the mortar near the middle bar. It wasn't much, Vimes knew, but it was a start.

“You don't require assistance, by any chance?” said the Patrician.

“No.”

“As you wish.”

The mortar was half-rotted, but the bars had been driven deep into the rock. Under their crusting of rust there was still plenty of iron. It was a long job, but it was something to do and required a blessed absence of thought. They couldn't take it away from him. It was a good, clean challenge; you knew if you went on chipping away, you'd win through eventually.

It was the “eventually” that was the problem. Eventually Great A 'Tuin would reach the end of the universe. Eventually the stars would go out. Eventually Nobby might have a bath, although that would probably involve a radical rethinking of the nature of Time.

He hacked at the mortar anyway, and then stopped as something small and pale fell down outside, quite slowly.

“Peanut shell?” he said.

The Librarian's face, surrounded by the inner-tube jowls of the Librarian's head, appeared upside down in the barred opening, and gave him a grin that wasn't any less terrible for being the wrong way up.

“Oook?”

The orangutan flopped down off the wall, grabbed a couple of bars, and pulled. Muscles shunted back and forward across its barrel chest in a complex pavane of effort. The mouthful of yellow teeth gaped in silent concentration.

There were a couple of dull “thungs” as the bars gave up and broke free. The ape flung them aside and reached into the gaping hole. Then the longest arms of the Law grabbed the astonished Vimes under his shoulders and pulled him through in one movement.

...

The rank surveyed their handiwork.

“Right,” said Nobby. “Now, what are the chances of a man standing on one leg with his hat on backwards and a handkerchief in his mouth hitting a dragon's voonerables? ”

“Mmph,” said Colon.

“It's pretty long odds,” said Carrot. “I reckon the hanky is a bit over the top, though.”

Colon spat it out. “Make up your minds,” he said. “Me leg's going to sleep.”

...

Vimes picked himself up off the greasy cobbles and stared at the Librarian. He was experiencing something which had come as a shock to many people, usually in much more unpleasant circumstances such as a brawl started in the Mended Drum when the ape wanted a bit of peace and quiet to enjoy a reflective pint, which was this: the Librarian might look like a stuffed rubber sack, but what it was stuffed with was muscle.

“That was amazing,” was all he could find to say. He looked down at the twisted bars, and felt his mind darken. He grabbed the bent metal. “You don't happen to know where Wonse is, do you?” he added.

“Eeek!” The Librarian thrust a tattered piece of parchment under his nose. “Eeek!”

Vimes read the words.

It hathe pleased . . . whereas . . . at the stroke of noone ... a maiden pure, yet high born . . . compact between ruler and ruled ...

“In my city!” he growled. “In my bloody city!”

He grabbed the Librarian by two handfuls of chest hair and pulled him up to eye height.

“What time is it?” he shouted.

“Oook!”

A long red-haired arm unfolded itself upwards. Vimes's gaze followed the pointing finger. The sun definitely had the look of a heavenly body that was nearly at the crest of its orbit and looking forward to a long, lazy coasting towards the blankets of dusk . . .

“I'm not bloody well going to have it, understand?” Vimes shouted, shaking the ape back and forth.

“Oook,” the Librarian pointed out, patiently.

“What? Oh. Sorry.” Vimes lowered the ape, who wisely didn't make an issue of it because a man angry enough to lift 300lbs of orangutan without noticing is a man with too much on his mind.

Now he was staring around the courtyard.

“Any way out of here?” he said. “Without climbing the walls, I mean.”

He didn't wait for an answer but loped around the walls until he reached a narrow, grubby door, and kicked it open. It hadn't been locked anyway, but he kicked it just the same. The Librarian trailed along behind, swinging on his knuckles.

The kitchen on the other side of the door was almost deserted, the staff having finally lost their nerve and decided that all prudent chefs refrained from working in an establishment where there was a mouth bigger than they were. A couple of palace guards were eating a cold lunch.

“Now,” said Vimes, as they half-rose, “I don't want to have to-”

They didn't seem to want to listen. One of them reached for a crossbow.

“Oh, the hell with it.” Vimes grabbed a butcher's knife from a block beside it and threw it.

There is an art in throwing knives and, even then, you need the right kind of knife. Otherwise it does just what this one did, which is miss completely.

The guard with the bow leaned sideways, righted himself, and found that a purple fingernail was gently blocking the firing mechanism. He looked around. The Librarian hit him right on top of his helmet.

The other guard shrank back, waving his hands frantically.

“Nonono!” he said. “It's a misunderstanding! What was it you said you didn't want to have to do? Nice monkey!”

“Oh, dear,” said Vimes. “Wrong!”

He ignored the terrified screaming and rummaged through the debris of the kitchen until he came up with a cleaver. He'd never felt really at home with swords, but a cleaver was a different matter. A cleaver had weight. It had purpose. A sword might have a certain nobility about it, unless it was the one belonging for example to Nobby, which relied on rust to hold it together, but what a cleaver had was a tremendous ability to cut things up.