He left the biology lesson-that no monkey was capable of bouncing someone up and down by their ankles-found a likely door, and hurried through it. This took him outside again, into the big cobbled area that surrounded the palace. Now he could get his bearings, now he could . . .

There was a boom in the air above him. A gale blew downwards, knocking him over.

The King of Ankh-Morpork, wings outspread, glided across the sky and settled for a moment on the palace gateway, talons gouging long scars in the stone as it caught its balance. The sun glittered off its arched back as it stretched its neck, roared a lazy billow of flames, and sprang into the air again.

Vimes made an animal-a mammalian animal-noise in the back of his throat, and ran out into the empty streets.

Silence filled the ancestral home of the Ramkins. The front door swung back and forth on its hinges, letting in the common, badly-brought up breeze which wandered through the deserted rooms, gawping and looking for dust on the top of the furniture. It wound up the stairs and banged through the door of Sybil Ramkin's bedroom, rattling the bottles on the dressing table and riffling through the pages of Diseases of the Dragon.

A really fast reader could have learned the symptoms of everything from Abated Heels to Zigzag Throat.

And down below, in the low, warm and foul-smelling shed that housed the swamp dragons, it seemed that Errol had got them all. Now he sat in the centre of his pen, swaying and moaning softly. White smoke rolled slowly from his ears and drifted towards the floor. From somewhere inside his swollen stomach came complex explosive hydraulic noises, as though desperate teams of gnomes were trying to drive a culvert through a cliff in a thunderstorm.

His nostrils flared, turning more or less of their own volition.

The other dragons craned over the pen walls, watching him cautiously.

There was another distant gastric roar. Errol shifted painfully.

The dragons exchanged glances. Then, one by one, they lay down carefully on the floor and put their paws over their eyes.

Nobby put his head on one side. “It looks promising,” he said critically. “We might be nearly there. I reckon the chances of a man with soot on his face, his tongue sticking out, standing on one leg and singing The Hedgehog Song ever hitting a dragon's voonerables would be ... what'd you say, Carrot?”

“A million to one, I reckon,” said Carrot virtuously.

Colon glared at them.

“Listen, lads,” he said, “you're not winding me up, are you?”

Carrot looked down at the plaza below them.

“Oh, bloody hell,” he said softly.

“Wassat?” said Colon urgently, looking around.

“They're chaining a woman to a rock!”

The rank stared over the parapet. The huge and silent crowd that lined the plaza stared too, at a white figure struggling between half a dozen palace guards.

“Wonder where they got the rock from?” said Colon. “We're on loam here, you know.”

“Fine strapping wench, whoever she is,” said Nobby approvingly, as one of the guards wheeled off bow-legged and collapsed. “That's one lad who won't know what to do with his evenin's for a few weeks. Got a mean right knee, so she has.”

“Anyone we know?” said Colon.

Carrot squinted.

“It's Lady Ramkin!” he said, his mouth dropping open.

“Never!”

“He's right. In a nightie,” said Nobby.

“The buggers!” Colon snatched up his bow and fumbled for an arrow. “I'll give 'em voonerables! Well-spoken lady like her, it's a disgrace!”

“Er,” said Carrot, who had glanced over his shoulder. “Sergeant?”

“This is what it comes to!” muttered Colon. "Decent women can't walk down the street without being eaten! Right, you bastards, you're . . . you're geography-''

'' Sergeant!'' Carrot repeated urgently.

“It's history, not geography,” said Nobby. “That's what you're supposed to say. History. 'You're history!' you say.”

“Well, whatever,” snapped Colon. “Let's see how-”

“Sergeant!”

Nobby was looking behind them, too.

“Oh, shit,” he said.

“Can't miss,” muttered Colon, taking aim.

“Sergeant!”

“Shut up, you two, I can't concentrate when you keep shout-”

“Sergeant, it's coming!”

The dragon accelerated.

The drunken rooftops of Ankh-Morpork blurred as it passed over, wings sneering at the air. Its neck stretched out straight ahead, the pilot flames of its nostrils streamed behind it, the sound of its flight panned across the sky.

Colon's hands shook. The dragon seemed to be aiming at his throat, and it was moving too fast, far too fast. . .

“This is it!” said Carrot. He glanced towards the Hub, in case any gods had forgotten what they were there for, and added, speaking slowly and distinctly, “It's a million-to-one-chance, but it might just work!”

“Fire the bloody thing!” screamed Nobby.

“Picking my spot, lad, picking my spot,” quavered Colon. “Don't you worry, lads, I told you this is my lucky arrow. First-class arrow, this arrow, had it since I was a lad, you'd be amazed at the things I shot at with this, don't you worry.”

He paused, as the nightmare bore down on him on wings of terror.

“Er, Carrot?” he said meekly.

“Yes, Sarge?”

“Did your old grandad ever say what a voonerable spot looks like?”

And then the dragon wasn't approaching any more, it was there, passing a few feet overhead, a streaming mosaic of scales and noise, filling the entire sky.

Colon fired.

They watched the arrow rise straight and true.

Vimes half-ran, half-staggered over the damp cobbles, out of breath and out of time.

It can't be like this, he thought wildly. The hero always cuts it fine, but he always get there just in the nick of time. Only the nick of time was probably five minutes ago.

And I'm not a hero. I'm out of condition, and I need a drink, and I get a handful of dollars a month without plumes allowance. That's not hero's pay. Heroes get kingdoms and princesses, and they take regular exercise, and when they smile the light glints off their teeth, ting. The bastards.

Sweat stung his eyes. The rush of adrenaline that had carried him out of the palace had spent itself, and was now exacting its inevitable toll.

He stumbled to a halt, and grabbed a wall to keep him upright while he gasped for air. And thus he saw the figures on the rooftop.

Oh, no! he thought. They're not heroes either! What do they think they're playing at?

It was a million-to-one chance. And who was to say that, somewhere in the millions of other possible universes, it might not have worked?

That was the sort of thing the gods really liked. But Chance, who sometimes can overrule even the gods, has 999,999 casting votes.

In this universe, for example, the arrow bounced off a scale and clattered away into oblivion.

Colon stared as the dragon's pointed tail passed overhead.

“It . . . missed . . .”he mouthed.

“But it couldn't of missed!” He stared red-eyed at the other two. “It was a sodding last desperate million-to-one chance!”

The dragon twisted its wings, swung its huge bulk around on a pivot of air, and bore down on the roof.

Carrot grabbed Nobby around the waist and laid a hand on Colon's shoulder.

The sergeant was weeping with rage and frustration.

“Million-to-bloody-one last desperate bloody chance!”

“Sarge-”

The dragon flamed.

It was a beautifully controlled line of plasma. It went through the roof like butter.

It cut through stairways.

It crackled into ancient timbers and made them twist like paper. It sliced into pipes.

It punched through floor after floor like the fist of an angry god and, eventually, reached the big copper vat containing a thousand gallons of freshly-made mature whisky-type spirit.

It burned into that, too.

Fortunately, the chances of anyone surviving the ensuing explosion were exactly a million-to-one.

The fireball rose like a-well, a rose. A huge orange rose, streaked with yellow. It took the roof with it and wrapped it around the astonished dragon, lifting it high into the air in a boiling cloud of broken timber and bits of piping.

The crowd watched in bemusement as the superhot blast flung it into the sky and barely noticed Vimes as he pushed his way, wheezing and crying, through the press of bodies.

He shouldered past a row of palace guards and shambled as fast as he could across the flagstones. No-one was paying him much attention at the moment.

He stopped.

It wasn't a rock, because Ankh-Morpork was on loam. It was just some huge remnant of mortared masonry, probably thousands of years old, from somewhere in the city foundations. Ankh-Morpork was so old now that what it was built on, by and large, was Ankh-Morpork.

It had been dragged into the centre of the plaza, and Lady Sybil Ramkin had been chained to it. She appeared to be wearing a nightie and huge rubber boots. By the look of her she had been in a fight, and Vimes felt a momentary pang of sympathy for whoever else had been involved. She gave him a look of pure fury.

“You!”

“You!”

He waved the cleaver vaguely.

“But why you-?” he began.

“Captain Vimes,” she said sharply, “you will oblige me by not waving that thing about and you will start putting it to its proper use!”

Vimes wasn't listening.

“Thirty dollars a month!” he muttered. “That's what they died for! Thirty dollars! And I docked some from Nobby. I had to, didn't I? I mean, that man could make a melon go rusty!”

“Captain Vimes!”

He focused on the cleaver.

“Oh,” he said. “Yes. Right!”

It was a good steel cleaver, and the chains were elderly and rather rusty iron. He hacked away, raising sparks from the masonry.

The crowd watched in silence, but several palace guards hurried towards him.

“What the hell do you think you're doing?” said one of them, who didn't have much imagination.

“What the hell do you think you're doing?” Vimes growled, looking up.

They stared at him.

“What?”

Vimes took another hack at the chains. Several loops tinkled to the ground.

“Right, you've asked for-” one of the guards began. Vimes's elbow caught him under his rib cage; before he collapsed, Vimes's foot kicked savagely at the other one's kneecaps, bringing his chin down ready for another stab with the other elbow.

“Right,” said Vimes absently. He rubbed the elbow. It was sheer agony.

He moved the cleaver to his other hand and hammered at the chains again, aware at the back of his mind that more guards were hurrying up, but with that special kind of run that guards had. He knew it well. It was the run that said, there's a dozen of us, let someone else get there first. It said, he looks ready to kill, no-one's paying me to get killed, maybe if I run slowly enough he'll get away . . .

No point in spoiling a good day by catching someone.

Lady Ramkin shook herself free. A ragged cheer went up and started to grow in volume. Even in their current state of mind, the people of Ankh-Morpork always appreciated a performance.