“Metterfor,” said Granny calmly.

“One of them.”

“Did you think it would be easy?” asked Granny. “Did you think you'd walk into their gates waving your staff? Here I am, I want to be a wizard, thank you very much?”

“He told me there's no women allowed in the University!”

“He's wrong.”

“No, I could tell he was telling the truth. You know, Granny, you can tell how -”

“Foolish child. All you could tell was that he thought he was telling the truth. The world isn't always as people see it.”

“I don't understand,” said Esk.

“You'll learn,” said Granny. “Now tell me. This dream. They wouldn't let you into their university, right?”

“Yes, and they laughed!”

“And then you tried to burn down the doors?”

Esk turned her head in Granny's lap and opened a suspicious eye.

“How did you know?”

Granny smiled, but as a lizard would smile.

“I was miles away,” she said. “I was bending my mind towards you, and suddenly you seemed to be everywhere. You shone out like a beacon, so you did. As for the fire - look around.”

In the halflight of dawn the plateau was a mass of baked clay. In front of Esk the cliff was glassy and must have flowed like tar under the onslaught; there were great gashes across it which had dripped molten rock and slag. When Esk listened she could hear the faint “pink, pink” of cooling rock.

“Oh,” she said, “did I do that?”

“So it would appear,” said Granny.

“But I was asleep! I was only dreaming!”

“It's the magic,” said Granny. “It's trying to find a way out. The witch magic and the wizard magic are, I don't know, sort of feeding off each other. I think.”

Esk bit her lip.

“What can I do?” she asked. “I dream of all sorts of things!”

“Well, for a start we're going straight to the University,” decided Granny. “They must be used to apprentices not being able to control magic and having hot dreams, else the place would have burned down years ago.”

She glanced towards the Rim, and then down at the broomstick beside her.

We will pass over the running up and down, the tightening of the broomstick's bindings, the muttered curses against dwarves, the brief moments of hope as the magic flickered fitfully, the horrible black feelings as it died, the tightening of the bindings again, the running again, the sudden catching of the spell, the scrambling aboard, the yelling, the takeoff ....

Esk clung to Granny with one hand and held her staff in the other as they, frankly, pottered along a few hundred feet above the ground. A few birds flew alongside them, interested in this new flying tree.

“Bugger off!” screamed Granny, taking off her hat and flapping it.

“We're not going very fast, Granny,” said Esk meekly.

“We're going quite fast enough for me!”

Esk looked around. Behind them the Rim was a blaze of gold, barred with cloud.

“I think we ought to go lower, Granny,” she said urgently. “You said the broomstick won't fly in sunlight.” She glanced down at the landscape below them. It looked sharp and inhospitable. It also looked expectant.

“I know what I'm doing, Miss,” snapped Granny, gripping the broomstick hard and trying to make herself as light as possible.

It has already been revealed that light on the Discworld travels slowly, the result of its passage through the Disc's vast and ancient magical field.

So dawn isn't the sudden affair that it is on other worlds. The new day doesn't erupt, it sort of sloshes gently across the sleeping landscape in the same way that the tide sneaks in across the beach, melting the sandcastles of the night. It tends to flow around mountains. If the trees are close together it comes out of woods cut to ribbons and sliced with shadows.

An observer on some suitable high point, let's say for the sake of argument a wisp of cirro-stratus on the edge of space, would remark on how lovingly the light spreads across the land, how it leaps forward on the plains and slows down when it encounters high ground, how beautifully it ....

Actually, there are some kinds of observers who, faced with all this beauty, will whine that you can't have heavy light and certainly wouldn't be able to see it, even if you could. To which one can only reply, so how come you're standing on a cloud?

So much for cynicism. But down on the Disc itself the broomstick barrelled forward on the cusp of dawn, dropping ever backward in the shadow of night.

“Granny!”

Day burst upon them. Ahead of the broomstick the rocks seemed to flash into flame as the light washed over them. Granny felt the stick lurch and stared with horrified fascination at the little scudding shadow below them. It was getting closer.

“What will happen when we hit the ground?”

“That depends if I can find some soft rocks,” said Granny in a preoccupied voice.

“The broomstick's going to crash! Can't we do anything?”

“Well, I suppose we could get off.”

“Granny,” said Esk, in the exasperated and remarkably adult voice children use to berate their wayward elders. “I don't think you quite understand. I don't want to hit the ground. It's never done anything to me.”

Granny was trying to think of a suitable spell and regretting that headology didn't work on rocks, and had she detected the diamond edge to Esk's tone perhaps she wouldn't have said: “Tell the broomstick that, then.”

And they would indeed have crashed. But she remembered in time to grab her hat and brace herself. The broomstick gave a shudder, tilted

- and the landscape blurred.

It was really quite a short trip but one that Granny knew she would always remember, generally around three o'clock in the morning after eating rich food. She would remember the rainbow colours that hummed in the rushing air, the horrible heavy feeling, the impression that something very big and heavy was sitting on the universe.

She would remember Esk's laughter. She would remember, despite her best efforts, the way the ground sped below them, whole mountain ranges flashing past with nasty zipping noises.

Most of all, she would remember catching up with the night. It appeared ahead of her, a ragged line of darkness running ahead of the remorseless morning. She stared in horrified fascination as the line became a blot, a stain, a whole continent of blackness that raced towards them.

For an instant they were poised on the crest of the dawn as it broke in silent thunder on the land. No surfer ever rode such a wave, but the broomstick broke through the broil of light and shot smoothly through into the coolness beyond.

Granny let herself breathe out.

Darkness took some of the terror out of the flight. It also meant that if Esk lost interest the broomstick ought to be able to fly under its own rather rusty magic.

“.” Granny said, and cleared her bone-dry throat for a second try. “Esk?”

“This is fun, isn't it? I wonder how I make it happen?”

“Yes, fun,” said Granny weakly. “But can I fly the stick, please? I don't want us to go over the Edge. Please?”

“Is it true that there's a giant waterfall all around the edge of the world, and you can look down and see stars?” said Esk.

“Yes. Can we slow down now?”

“I'd like to see it.”

“No! I mean, no, not now.”

The broomstick slowed. The rainbow bubble around it vanished with an audible pop. Without a jolt, without so much as a shudder, Granny found herself flying at a respectable speed again.

Granny had built a solid reputation on always knowing the answer to everything. Getting her to admit ignorance, even to herself, was an astonishing achievement. But the worm of curiosity was chewing at the apple of her mind.

“How,” she said at last, “did you do that?”

There was a thoughtful silence behind her. Then Esk said: “I don't know. I just needed it, and it was in my head. Like when you remember something you've forgotten.”

“Yes, but how?”

“I - I don't know. I just had a picture of how I wanted things to be, and, and I, sort of - went into the picture.”

Granny stared into the night. She had never heard of magic like that, but it sounded awfully powerful and probably lethal. Went into the picture! Of course, all magic changed the world in some way, wizards thought there was no other use for it - they didn't truck with the idea of leaving the world as it was and changing the people -but this sounded more literal. It needed thinking about. On the ground.

For the first time in her life Granny wondered whether there might be something important in all these books people were setting such store by these days, although she was opposed to books on strict moral grounds, since she had heard that many of them were written by dead people and therefore it stood to reason reading them would be as bad as necromancy. Among the many things in the infinitely varied universe with which Granny did not hold was talking to dead people, who by all accounts had enough troubles of their own.

But not, she was inclined to feel, as many as her. She looked down bemusedly at the dark ground and wondered vaguely why the stars were below her.

For a cardiac moment she wondered if they had indeed flown over the edge, and then she realised that the thousands of little pinpoints below her were too yellow, and flickered. Besides, whoever heard of stars arranged in such a neat pattern?

“It's very pretty,” said Esk. “Is it a city?”

Granny scanned the ground wildly. If it was a city, then it was too big. But now she had time to think about it, it certainly smelled like a lot of people.

The air around them reeked of incense and grain and spices and beer, but mainly of the sort of smell that was caused by a high water table, thousands of people, and a robust approach to drainage.

She mentally shook herself. The day was hard on their heels. She looked for an area where the torches were dim and widely spaced, reasoning that this would mean a poor district and poor people did not object to witches, and gently pointed the broom handle downwards.

She managed to get within five feet of the ground before dawn arrived for the second time.

The gates were indeed big and black and looked as if they were made out of solid darkness.

Granny and Esk stood among the crowds that thronged the square outside the University and stared up at them. Finally Esk said: “I can't see how people get in.”

“Magic, I expect,” said Granny sourly. “That's wizards for you. Anyone else would have bought a doorknocker.”

She waved her broomstick in the direction of the tall doors.

“You've got to say some hocuspocus word to get in, I shouldn't wonder,” she added.

They had been in Ankh-Morpork for three days and Granny was beginning to enjoy herself, much to her surprise. She had found them lodgings in The Shades, an ancient part of the city whose inhabitants were largely nocturnal and never enquired about one another's business because curiosity not only killed the cat but threw it in the river with weights tied to its feet. The lodgings were on the top floor next to the well-guarded premises of a respectable dealer in stolen property because, as Granny had heard, good fences make good neighbors.