In fact all sorts of sounds managed to breach the high grim windowless walls, and from keen questioning of servants the younger Fools picked up a vision of the city beyond. There were taverns out there, and parks. There was a whole bustling world, in which the students and apprentices of the various Guilds and Colleges took a full ripe part, either by playing tricks on it, running through it shouting, or throwing parts of it up. There was laughter which paid no attention to the Five Cadences or Twelve Inflections. And – although the students debated this news in the dormitories at night – there was apparently unauthorised humour, delivered freestyle, with no reference to the Monster Fun Book or the Council or anyone.

Out there, beyond the stained stonework, people were telling jokes without reference to the Lords of Misrule.

It was a sobering thought. Well, not a sobering thought in actual fact, because alcohol wasn't allowed in the Guild. But if it was, it would have been.

There was nowhere more sober than the Guild.

The Fool spoke bitterly of the huge, redfaced Brother Prankster, of evenings learning the Merry Jests, of long mornings in the freezing gymnasium learning the Eighteen Pratfalls and the accepted trajectory for a custard pie. And juggling. Juggling! Brother Jape, a man with a soul like cold boiled string, taught juggling. It wasn't that the Fool was bad at juggling that reduced him to incoherent fury. Fools were expected to be bad at juggling, especially if juggling inherently funny items like custard pies, flaming torches or extremely sharp cleavers. What had Brother Jape laying about him in red-hot, clanging rage was the fact that the Fool was bad at juggling because he wasn 't any good at it.

'Didn't you want to be anything else?' said Magrat.

'What else is there?' said the Fool. 'I haven't seen anything else I could be.'

Student Fools were allowed out, in the last year of training, but under a fearsome set of restrictions. Capering miserably through the streets he'd seen wizards for the first time, moving like dignified carnival floats. He'd seen the surviving assassins, foppish, giggling young men in black silk, as sharp as knives underneath; he'd seen priests, their fantastic costumes only slightly marred by the long rubber sacrificial aprons they wore for major services. Every trade and profession had its costume, he saw, and he realised for the first time that the uniform he was wearing had been carefully and meticulously designed for no other purpose than making its wearer look like a complete and utter pillock.

Even so, he'd persevered. He'd spent his whole life persevering.

He persevered precisely because he had absolutely no talent, and because grandfather would have flayed him alive if he didn't. He memorised the authorised jokes until his head rang, and got up even earlier in the morning to juggle until his elbows creaked. He had perfected his grasp of the comic vocabulary until only the very senior Lords could understand him. He'd capered and clowned with an impenetrable grim determination and he'd graduated top of his year and had been awarded the Bladder of Honour. He'd dropped it down the privy when he came home.

Magrat was silent.

The Fool said, 'How did you get to be a witch?'

'Um?'

'I mean, did you go to a school or something?'

'Oh. No. Goodie Whemper just walked down to the village one day, got all us girls lined up, and chose me. You don't choose the Craft, you see. It chooses you.'

'Yes, but when do you actually become a witch?'

'When the other witches treat you as one, I suppose.' Magrat sighed. 'If they ever do,' she added. 'I thought they would after I did that spell in the corridor. It was pretty good, after all.'

'Marry, t'was a rite of passage,' said the Fool, unable to stop himself. Magrat gave him a blank look. He coughed.

'The other witches being those two old ladies?' he said, relapsing into his usual gloom.

'Yes.'

'Very strong characters, I imagine.'

'Very,' said Magrat, with feeling.

'I wonder if they ever met my grandad,' said the Fool.

Magrat looked at her feet.

'They're quite nice really,' she said. 'It's just that, well, when you're a witch you don't think about other people. I mean, you think about them, but you don't actually think about their feelings, if you see what I mean. At least, not unless you think about it.' She looked at her feet again.

'You're not like that,' said the Fool.

'Look, I wish you'd stop working for the duke,' said Magrat desperately. 'You know what he's like. Torturing people and setting fire to their cottages and everything.'

'But I'm his Fool,' said the Fool. 'A Fool has to be loyal to his master. Right up until he dies. I'm afraid it's tradition. Tradition is very important.'

'But you don't even like being a Fool!'

'I hate it. But that's got nothing to do with it. If I've got to be a Fool, I'll do it properly.'

'That's really stupid,' said Magrat.

'Foolish, I'd prefer.'

The Fool had been edging along the log. 'If I kiss you,' he added carefully, 'do I turn into a frog?'

Magrat looked down at her feet again. They shuffled themselves under her dress, embarrassed at all this attention.

She could sense the shades of Gytha Ogg and Esme Weatherwax on either side of her. Granny's spectre glared at her. A witch is master of every situation, it said.

Mistress, said the vision of Nanny Ogg, and made a brief gesture involving much grinning and waving of forearms.

'We shall have to see,' she said.

It was destined to be the most impressive kiss in the history of foreplay.

Time, as Granny Weatherwax had pointed out, is a subjective experience. The Fool's years in the Guild had been an eternity whereas the hours with Magrat on the hilltop passed like a couple of minutes. And, high above Lancre, a double handful of seconds extended like taffy into hours of screaming terror.

'Ice!' screamed Granny. 'It's iced up!'

Nanny Ogg came alongside, trying vainly to match courses with the tumbling, bucking broomstick. Octarine fire crackled over the frozen bristles, shorting them out at random. She leaned over and snatched a handful of Granny's skirt.

'I tole you it was daft!' she shouted. 'You went all through all that wet mist and then up into the cold air, you daft besom!'

'You let go of my skirt, Gytha Ogg!'

'Come on, grab hold o'mine. You're on fire at the back there!'

They shot through the bottom of the cloud bank and screamed in unison as the shrub-covered ground emerged from nowhere and aimed itself directly at them.

And went past.

Nanny looked down a black perspective at the bottom of which a boil of white water was dimly visible. They had flown over the edge of Lancre Gorge.

Blue smoke was pouring out of Granny's broomstick but she hung on, determined, and forced it around.

'What the hell you doing?' roared Nanny.

'I can follow the river,' Granny Weatherwax screamed, above the crackle of flames. 'Don't you worry!'

'You come aboard, d'you hear? It's all over, you can't do it . . .'

There was a small explosion behind Granny and several handfuls of burning bristles broke off and whirled away into the booming depths of the gorge. Her stick jerked sideways and Nanny grabbed her around the shoulders as a gout of fire snapped another binding.

The blazing broomstick shot from between her legs, twisted in the air, and went straight upwards, trailing sparks and making a noise like a wet finger dragged around the top of a wineglass.

This left Nanny flying upside down, supporting Granny Weatherwax at arm's length. They stared into one another's face and screamed.

'I can't pull you up!'

'Well, I can't climb up, can I? Act your age, Gytha!'

Nanny considered this. Then she let go.

Three marriages and an adventurous girlhood had left Nanny Ogg with thigh muscles that could crack coconuts, and the G-forces sucked at her as she forced the speeding stick down and around in a tight loop.

Ahead of her she made out Granny Weatherwax dropping like a stone, one hand clutching her hat, the other trying to prevent gravity from seeing up her skirts. She urged the stick forwards until it creaked, snatched the falling witch around the waist, fought the plunging stick back up to level flight, and sagged.

The subsequent silence was broken by Granny Weatherwax saying, 'Don't you ever do that again, Gytha Ogg.'

'I promise.'

'Now turn us around. We're heading for Lancre Bridge, remember?'

Nanny obediently turned the broomstick, brushing the canyon walls as she did so.

'It's still miles to go,' she said.

'I mean to do it,' said Granny. 'There's plenty of night left.'

'Not enough, I'm thinking.'

'A witch doesn't know the meaning of the word “failure”. Gytha.'

They shot up into the clear air again. The horizon was a line of golden light as the slow dawn of the Disc sped across the land, bulldozing the suburbs of the night.

'Esme?' said Nanny Ogg, after a while.

'What?'

'It means “lack of success”.'

They flew in chilly silence for several seconds.

'I was speaking wossname. Figuratively,' said Granny.

'Oh. Well. You should of said.'

The line of light was bigger, brighter. For the first time a flicker of doubt invaded Granny Weatherwax's mind, puzzled to find itself in such unfamiliar surroundings.

'I wonder how many cockerels there are in Lancre?' she said quietly.

'Was that one of them wossname questions?'

'I was just wondering.'

Nanny Ogg sat back. There were thirty-two of crowing age, she knew. She knew because she'd worked it out last night – tonight - and had given Jason his instructions. She had fifteen grown-up children and innumerable grandchildren and great-grandchildren, and they'd had most of the evening to get into position. It should be enough.

'Did you hear that?' said Granny. 'Over Razorback way?'

Nanny looked innocently across the misty landscape. Sound travelled very clearly in these early hours.

'What?' she said.

'Sort of an “urk” noise?'

'No.'

Granny spun around.

'Over there,' she said. 'I definitely heard it this time. Something like “cock-a-doo-arrgh”.'

'Can't say I did, Esme,' said Nanny, smiling at the sky. 'Lancre Bridge up ahead.'

'And over there! Right down there! It was a definite squawk!'

'Dawn chorus, Esme, I expect. Look, only half a mile to go.'

Granny glared at the back of her colleague's head.

'There's something going on here,' she said.

'Search me, Esme.'

'Your shoulders are shaking!'

'Lost my shawl back there. I'm a bit chilly. Look, we're nearly there.'

Granny glared ahead, her mind a maze of suspicions. She was going to get to the bottom of this. When she had time.

The damp logs of Lancre's main link to the outside world drifted gently underneath them. From the chicken farm half a mile away came a chorus of strangled squawks and a thud.

'And that? What was that, then?' demanded Granny.

'Fowl pest. Careful, I'm bringing us down.'

'Are you laughing at me?'

'Just pleased for you, Esme. You'll go down in history for this, you know.'

They drifted between the timbers of the bridge. Granny Weatherwax alighted cautiously on the greasy planking and adjusted her dress.

'Yes. Well,' she added, nonchalantly.

'Better than Black Aliss, everyone'll say,' Nanny Ogg went on.

'Some people will say anything,' said Granny. She peered over the parapet at the foaming torrent far below, and then up at the distant outcrop on which stood Lancre Castle.

'Do you think they will?' she added, nonchalantly.

'Mark my words.'