Lady D'Arrangement's shoes hadn't fitted. Besides, Granny was attached to her boots. They had complicated iron fixtures, and toecaps like battering rams. When it came to dancing, Granny's boots went exactly wherever they wanted to go.

She steered her helpless and slightly crippled partner towards Nanny Ogg, who had already cleared quite a space around her. What Granny could achieve with two pounds of hobnailed syncopation Nanny Ogg could achieve merely with her bosom.

It was a large and experienced bosom, and not one that was subject to restraint. As Nanny Ogg bounced down, it went up; when she gyrated right, it hadn't finished twirling left. In addition, Nanny's feet moved in a complicated jig step regardless of the actual tempo, so that while her body actually progressed at the speed of a waltz her feet were doing something a bit nearer to a hornpipe. The total effect obliged her partner to dance several feet away, and many surrounding couples to stop dancing just to watch in fascination, in case the build-up of harmonic vibrations dropped her into the chandeliers.

Granny and her helpless partner whirled past.

"Stop showin' off," Granny hissed, and disappeared into the throng again.

"Who's your friend?" said Casanunda.

"She's - " Nanny began.

There was a blast of trumpets.

"That was a bit off the beat," she said.

"No, that means the Duc is arriving," said Casanunda.

The band stopped playing. The couples, as one, turned and faced the main staircase.

There were two figures descending in stately fashion.

My word, he's a sleek and handsome devil, Nanny told herself. It just goes to show. Esme's right. You can never tell by lookin'.

And her...

... that's Lily Weatherwax?

The woman wasn't masked.

Give or take the odd laughter line and wrinkle, it was Granny Weatherwax to the life.

Almost...

Nanny found she was turning to find the white eagle head in the crowd. All heads were turned to die staircase, but there was one staring as if her gaze was a steel rod.

Lily Weatherwax wore white. Until that point it had never occurred to Nanny Ogg that there could be different colours of white. Now she knew better. The white of Lily Weatherwax's dress seemed to radiate; if all the lights went out, she felt, Lily's dress would glow. It had style. It gleamed, and had puffed sleeves and was edged with lace.

And Lily Weatherwax looked - Nanny Ogg had to admit it - younger. There was the same bone structure and fine Weatherwax complexion, but it looked... less worn.

If that's what bein' bad does to you, Nanny thought, I could of done with some of that years ago. The wages of sin is death but so is the salary of virtue, and at least the evil get to go home early on Fridays.

The eyes were the same, though. Somewhere in the genetics of the Weatherwaxes was a piece of sapphire. Maybe generations of them.

The Duc was unbelievably handsome. But that was understandable. He was wearing black. Even his eyes wore black.

Nanny surfaced, and pushed her way through the throng to Granny Weatherwax.

"Esme?"

She grabbed Granny's arm.

"Esme?"

"Hmm?"

Nanny was aware that the crowd was moving, parting like a sea, between the staircase and the chaise-longue at the far end of the hall.

Granny Weatherwax's knuckles were as white as her dress.

"Esme? What's happening? What are you doing?" said Nanny.

"Trying... to... stop... the story," said Granny.

"What's she doing, then?"

"Letting... things... happen!"

The crowd were pulling back past them. It didn't seem to be a conscious thing. It was just happening that a sort of corridor was forming.

The Prince walked slowly along it. Behind Lily, faint images hung in the air so that she appeared to be followed by a succession of fading ghosts.

Magrat stood up.

Nanny was aware of a rainbow hue in the air. Possibly there was the tweeting of bluebirds.

The Prince took Magrat by the hand.

Nanny glanced up at Lily Weatherwax, who had remained a few steps up from the foot of the stairs and was smiling beneficently.

Then she tried to put a focus on the future.

It was horribly easy.

Normally the future is branching off at every turn and it's only possible to have the haziest idea of what is likely to happen, even when you're as temporally sensitive as a witch. But here there were stories coiled around the tree of events, bending it into a new shape.

Granny Weatherwax wouldn't know what a pattern of quantum inevitability was if she found it eating her dinner. If you mentioned the words ‘paradigms of space-time' to her she'd just say ‘What?" But that didn't mean she was ignorant. It just meant that she didn't have any truck with words, especially gibberish. She just knew that there were certain things that happened continually in human history, like three-dimensional cliches. Stories.

"And now we're part of it! And I can't stop it," said Granny. "There's got to be a place where I can stop it, and I can't find it!"

The band struck up. It was playing a waltz.

Magrat and the Prince whirled around the dance floor once, never taking their eyes off each other. Then a few couples dared to join them. And then, as if the whole ball was a machine whose spring had been wound up again, the floor was full of dancing couples and the sounds of conversation flowed back into the void.

"Are you going to introduce me to your friend?" said Casanunda, from somewhere near Nanny's elbow. People swept past them.

"It's all got to happen," said Granny, ignoring the low-level interruption. "Everything. The kiss, the clock striking midnight, her running out and losing the glass slipper, everything."

"Ur, yuk," said Nanny, leaning on her partner's head. "I'd rather lick toads."

"She looks just my type," said Casanunda, his voice slightly muffled. "I've always been very attracted to dominant women."

The witches looked at the whirling couple, who were staring into one another's eyes.

"I could trip them up, no trouble," said Nanny.

"You can't. That's not something that can happen."

"Well, Magrat's sensible... more or less sensible," said Nanny. "Maybe she'll notice something's wrong."

"I'm good at what I do, Gytha Ogg," said Granny. "She won't notice nothing until the clock strikes midnight."

They both turned to look up. It was barely nine.

"Y'know," said Nanny Ogg. "Clocks don't strike midnight. Seems to me they just strike twelve. I mean, it's just a matter of bongs."

They both looked up at the clock again.

In the swamp, Legba the black cockerel crowed. He always crowed at sunset.

Nanny Ogg pounded up another flight of stairs and leaned against the wall to catch her breath.

It had to be somewhere round here.

"Another time you'll learn to keep your mouth shut, Gytha Ogg," she muttered.

"I expect we're leaving the hurly-burly of the ball for an intimate tete-a-tete somewhere?" said Casanunda hopefully, trotting along behind her.

Nanny tried to ignore him and ran along a dusty passage. There was a balcony rail on one side, looking down into the ballroom. And there...

... a small wooden door.

She rammed it open with her elbow. Within, mechanisms whirred in counterpoint to the dancing figures below as if the clock was propelling them, which, in a metaphorical sense, it was.

Clockwork, Nanny thought. Once you know about clockwork, you know about everything.

I wish I bloody well knew about clockwork.

"Very cosy," said Casanunda.

She squeezed through the gap and into the clock space. Cog-wheels clicked past her nose.

She stared at them for a moment.

Lawks. All this just to chop Time up into little bits.

"It might be just the teensiest bit cramped," said Casanunda, from somewhere near her armpit. "But needs must, ma'am. I remember once in Quirm, there was this sedan chair and..."