“Oh.”

He's in a dungeon in his own palace with a raving lunatic in charge upstairs, and a dragon burning the city, and he thinks he's got the world where he wants it. It must be something about high office. The altitude sends people mad.

“You, er, you don't mind if I have a look around, > do you?” he said.

“Feel free,” said the Patrician.

Vimes paced the length of the dungeon and checked the door. It was heavily barred and bolted, and the lock was massive.

Then he tapped the walls in what might possibly be hollow places. There was no doubt that it was a well-built dungeon. It was the kind of dungeon you'd feel good about having dangerous criminals put in. Of course, in those circumstances you'd prefer there to be no trapdoors, hidden tunnels or secret ways of escape.

These weren't those circumstances. It was amazing what several feet of solid stone did to your sense of perspective.

“Do guards come in here?” he demanded.

“Hardly ever,” said the Patrician, waving a chicken leg. “They don't bother about feeding me, you see. The idea is that one should moulder. In fact,” he said, “up 'til recently I used to go to the door and groan a bit every now and then, just to keep them happy.”

“They're bound to come in and check, though?” said Vimes hopefully.

“Oh, I don't think we should tolerate that,” said the Patrician.

' 'How are you going to prevent them?''

Lord Vetinari gave him a pained look.

“My dear Vimes,” he said, “I thought you were an observant man. Did you look at the door?”

“Of course I did,” said Vimes, and added, "sir. It's bloody massive.''

"Perhaps you should have another look?''

Vimes gaped at him, and then stamped across the floor and glared at the door. It was one of the popular dread portal variety, all bars and bolts and iron spikes and massive hinges. No matter how long he looked at it, it didn't become any less massive. The lock was one of those dwarfish-made buggers that it'd take years to pick. All in all, if you had to have a symbol for something totally immovable, that door was your man. The Patrician appeared alongside him in heart-stopping silence.

“You see,” he said, “it's always the case, is it not, that should a city be overtaken by violent civil unrest the current ruler is thrown into the dungeons? To a certain type of mind that is so much more satisfying than mere execution.”

“Well, okay, but I don't see-” Vimes began. “And you look at this door and what you see is a really strong cell door, yes?”

“Of course. You've only got to look at the bolts and-”

“You know, I'm really rather pleased,” said Lord Vetinari quietly.

Vimes stared at the door until his eyebrows ached. And then, just as random patterns in cloud suddenly, without changing in any way, become a horse's head or a sailing ship, he saw what he'd been looking at all along.

A sense of terrifying admiration overcame him. He wondered what it was like in the Patrician's mind. All cold and shiny, he thought, all blued steel and icicles and little wheels clicking along like a huge clock. The kind of mind that would carefully consider its own downfall and turn it to advantage.

It was a perfectly normal dungeon door, but it all depended on your sense of perspective.

In this dungeon the Patrician could hold off the world.

All that was on the outside was the lock.

All the bolts and bars were on the inside.

The rank clambered awkwardly across the damp rooftops as the morning mist was boiled off by the sun. Not that there would be any clear air today-sticky swathes of smoke and stale steam wreathed the city and filled the air with the sad smell of dampened cinders.

“What is this place?” said Carrot, helping the others along a greasy walkway.

Sergeant Colon looked around at the forest of chimneys.

“We're just above Jimkin Bearhugger's whisky distillery,” he said. “On a direct line, see, between the palace and the plaza. It's bound to fly over here.”

Nobby looked wistfully over the side of the building.

“I bin in there once,” he said. “Checked the door one dark night and it just came open in my hand.”

“Eventually, I expect,” said Colon sourly.

“Well, I had to go in, din't I, to check there was no miscreanting going on. Amazing place in there. All pipes and stuff. And the smell!”

“ 'Every bottle matured for up to seven minutes',” quoted Colon. " 'Ha' a drop afore ye go', it says on the label. Damn right, too. I had a drop once, and I went all day.''

He knelt down and unwrapped the long sacking package he had been manhandling, with extreme difficulty, during the climb. This revealed a longbow of ancient design and a quiver of arrows.

He picked up the bow slowly, reverentially, and ran his pudgy fingers along it.

“You know,” he said quietly, “I was damn good with this, when I were a lad. The captain should of let me have a go the other night.”

“You keep on telling us,” said Nobby unsympathetically.

“Well, I used to win prizes.” The sergeant unwound a new bowstring, looped it around one end of the bow, stood up, pressed down, grunted a bit ...

“Er. Carrot?” he said, slightly out of breath.

“Yes, Sarge?”

“You any good at stringing bows?”

Carrot grasped the bow, compressed it easily, and slipped the other end of the string into place.

“That's a good start, Sarge,” said Nobby.

“Don't you be sarcastic with me, Nobby! It ain't strength, it's keenness of eye and steadiness of hand what counts. Now you pass me an arrow. Not that one!”

Nobby's fingers froze in the act of grasping a shaft.

“That's my lucky arrow!” spluttered Colon. “None of you is to touch my lucky arrow!”

“Looks just like any other bloody arrow to me, Sarge,” said Nobby mildly.

“That's the one I shall use for the actual wossname, the coup de grass,” said Colon. “Never let me down, my lucky arrow didn't. Hit whatever I shot at. Hardly even had to aim. If that dragon's got any voonerables, that arrow'll find 'em.”

He selected an identical-looking but presumably less lucky arrow and nocked it. Then he looked around the rooftops with a speculative eye.

“Better get my hand in,” he muttered. “Of course, once you learn you never forget, it's like riding a- riding a-riding something you never forget being able to ride.”

He pulled the bowstring back to his ear, and grunted.

“Right,” he wheezed, as his arm trembled with the tension like a branch in a gale. “See the roof of the Assassins' Guild over there?” They peered through the grubby air.

“Right, then,” said Colon. “And do you see the weathervane on it? Do you see it?”

Carrot glanced at the arrowhead. It was weaving back and forth in a series of figure-eights.

“It's a long way off, Sarge,” said Nobby doubtfully.

“Never you mind me, you keep your eyes on the weathervane,” groaned the sergeant.

They nodded. The weathervane was in the shape of a creeping man with a big cloak; his outstretched dagger was always turned to stab the wind. At this distance, though, it was tiny.

“Okay,” panted Colon. “Now, d'you see the man's eye?”

“Oh, come on, ” said Nobby.

“Shutup, shutup, shutup!” groaned Colon. “Do you see it, I said!”

“I think I can see it, Sarge,” said Carrot loyally.

“Right. Right,” said the sergeant, swaying backwards and forwards with effort. “Right. Good lad. Okay. Now keep an eye on it, right?”

He grunted, and loosed the arrow.

Several things happened so fast that they will have to be recounted in stop-motion prose. Probably the first was the bowstring slapping into the soft inner part of Colon's wrist, causing him to scream and drop the bow. This had no effect on the path of the arrow, which was already flying straight and true towards a gargoyle on the rooftop just across the road. It hit it on the ear, bounced, ricocheted off a wall six feet away, and headed back towards Colon apparently at a slightly increased speed, going past his ear with a silky humming noise.

It vanished in the direction of the city walls.

After a while Nobby coughed and gave Carrot a look of innocent inquiry.

“About how big,” he said, “is a dragon's voonerables, roughly?”

“Oh, it can be a tiny spot,” said Carrot helpfully.

“I was sort of afraid of that,” said Nobby. He wandered to the edge of the roof, and pointed downwards. “There's a pond just here,” he said. “They use it for cooling water in the stills. I reckon it's pretty deep, so after the sergeant has shot at the dragon we can jump in it. What d'you say?”

“Oh, but we don't need to do that,” said Carrot. “Because the sergeant's lucky arrow would of hit the spot and the dragon'll be dead, so we won't have anything to worry about.”

“Granted, granted,” said Nobby hurriedly, looking at Colon's scowling face. “But just in case, you know, if by a million-to-one chance he misses-I'm not saying he will, mark you, you just have to think of all eventualities-if, by incredible bad luck, he doesn't quite manage to hit the voonerable dead on, then your dragon is going to lose his rag, right, and it's probably a good idea to not be here. It's a long shot, I know. Call me a worry-wart if you like. That's all I'm saying.”

Sergeant Colon adjusted his armour haughtily.

“When you really need them the most,” he said, “million-to-one chances always crop up. Well-known fact.”

“The sergeant is right, Nobby,” said Carrot virtuously. “You know that when there's just one chance which might just work-well, it works. Otherwise there'd be no-” he lowered his voice-“I mean, it stands to reason, if last desperate chances didn't work, there'd be no ... well, the gods wouldn't let it be any other way. They wouldn't.”

As one man, the three of them turned and looked through the murky air towards the hub of the Disc-world, thousands of miles away. Now the air was grey with old smoke and mist shreds, but on a clear day it was possible to see Cori Celesti, home of the gods. Site of the home of the gods, anyway. They lived in Dunmanifestin, the stuccoed Valhalla, where the gods faced eternity with the kind of minds that were at a loss to know what to do to pass a wet afternoon. They played games with the fates of men, it was said. Exactly what game they thought they were playing at the moment was anyone's guess.

But of course there were rules. Everyone knew there were rules. They just had to hope like Hell that the gods knew the rules, too.

“It's got to work,” mumbled Colon. “I'll be using my lucky arrow 'n all. You're right. Last hopeless chances have got to work. Nothing makes any sense otherwise. You might as well not be alive.”

Nobby looked down at the pond again. After a moment's hesitation Colon joined him. They had the speculative faces of men who had seen many things, and knew that while you could of course depend on heroes, and kings, and ultimately on gods, you could really depend on gravity and deep water.

“Not that we'll need it,” said Colon virtuously.