“You little bastard,” he said. “I'm going to knock your block off.”

He peered closer.

“What's that on your back? A hump?”

“Ah, you've noticed the stepladder,” said the low highwayman. “Let me demonstrate-”

“What's happening?” said Ridcully, back in the coach.

“Um, a dwarf has just climbed up a small stepladder and kicked the coachman in the middle of the road,” said Ponder.

“That's something you don't see every day,” said Ridcully. He looked happy. Up to now, the journey had been quite uneventful.

“Now he's coming toward us.”

“Oh, good.” The highwayman stepped over the groaning body of the driver and marched toward the door of the coach, dragging his stepladder behind him.

He opened the door.

“Your money or, I'm sorry to say, your-”

A blast of octarine fire blew his hat off. The dwarfs expression did not change. ' “I wonder if I might be allowed to rephrase my demands?”

Ridcully looked the elegantly dressed stranger up and down or, rather, down and further down.

“You don't look like a dwarf,” he said, “apart from the height, that is.”

“Don't look like a dwarf apart from the height?”

“I mean, the helmet and iron boots department is among those you are lacking in,” said Ridcully.

The dwarf bowed and produced a slip of pasteboard from one grubby but lace-clad sleeve.

“My card,” he said.

It read:

Giamo Casanunda

WORLD'S SECOND GREATEST LOVER

We Never Sleep

FINEST SWORDSMAN - SOLDIER OF FORTUNE

OUTRAGEOUS LIAR - STEPLADDERS REPAIRED

Ponder peered over Ridcully's shoulder.

“Are you really an outrageous liar?”

“No.”

“Why are you trying to rob coaches, then?”

“I am afraid I was waylaid by bandits.”

“But it says here,” said Ridcully, “that you are a finest swordsman.”

“I was outnumbered.”

“How many of them were there?”

“Three million.”

“Hop in,” said Ridcully

Casanunda threw his stepladder into the coach and then peered into the gloom.

“Is that an ape asleep in there?”

“Yes.”

The Librarian opened one eye.

“What about the smell?”

“He won't mind.”

“Hadn't you better apologize to the coachman?” said

Ponder.

“No, but I could kick him again harder if he likes.”

“And that's the Bursar,” said Ridcully, pointing to Exhibit B, who was sleeping the sleep of the near-terminally overdosed on dried frog pills. “Hey, Bursar? Bursssaaar? No, he's out like a light. Just push him under the seat. Can you play Cripple Mr. Onion?”

“Not very well.”

“Capital!”

Half an hour later Ridcully owed the dwarf $8,000.

“But I put it on my visiting card,” Casanunda pointed out. “Outrageous liar. Right there.”

“Yes, but I thought you were lying!”

Ridcully sighed and, to Ponder's amazement, produced a bag of coins from some inner recess. They were large coins and looked suspiciously realistic and golden.

Casanunda might have been a libidinous soldier of fortune by profession but he was a dwarf by genetics, and there are some things dwarfs know.

“Hmm,” he said. “You don't have ”outrageous liar“ on your visiting card, by any chance?”

“No!” said Ridcully excitedly

“It's just that I can recognize chocolate money when I see it.”

“You know,” said Ponder, as the coach jolted along a canyon, “this reminds me of that famous logical puzzle.”

“What logical puzzle?” said the Archchancellor. “Well,” said Ponder, gratified at the attention, “it appears that there was this man, right, who had to choose between going through two doors, apparently, and the guard on one door always told the truth and the guard on the other door always told a lie, and the thing was, behind one door was certain death, and behind the other door was freedom, and he didn't know which guard was which, and he could only ask them one question and so: what did he ask?”

The coach bounced over a pothole. The Librarian turned over in his sleep.

“Sounds like Psychotic Lord Hargon of Quirm to me,” said Ridcully, after a while.

“That's right,” said Casanunda. “He was a devil for jokes like that. How many students can you get in an Iron Maiden, that kind of thing.”

“So this was at his place, then, was it?” said Ridcully.

“What? I don't know,” said Ponder.

“Why not? You seem to know all about it.”

“I don't think it was anywhere. It's a puzzle.”

“Hang on,” said Casanunda, “I think I've worked it out. One question, right?”

“Yes,” said Ponder, relieved.

“And he can ask either guard?”

“Yes.”

“Oh, right. Well, in that case he goes up to the smallest guard and says, Tell me which is the door to freedom if you don't want to see the colour of your kidneys and incidentally I'm walking through it behind you, so if you're trying for the Mr. Clever Award just remember who's going through it first.'”

“No, no, no!”

“Sounds logical to me,” said Ridcully “Very good thinking.”

“But you haven't got a weapon!”

“Yes I have. I wrested it from the guard while he was considering the question,” said Casanunda.

“Clever,” said Ridcully. “Now that, Mr. Stibbons, is logical thought. You could learn a lot from this man-”

“-dwarf-”

“-sorry, dwarf. He doesn't go on about parasite universes all the time.”

“Parallel!” snapped Ponder, who had developed a very strong suspicion that Ridcully was getting it wrong on purpose.

“Which ones are the parasite ones, then?”

“There aren't any! I mean, there aren't any, Archchancellor.[15] Parallel universes, I said. Universes where things didn't happen like-” He hesitated. “Well, you know that girl?”

“What girl?”

“The girl you wanted to marry?”

“How'd you know that?”

“You were talking about her just after lunch.”

“Was I? More fool me. Well, what about her?”

“Well. . . in a way, you did marry her,” said Ponder.

Ridcully shook his head. “Nope. Pretty certain I didn't. You remember that sort of thing.”

“Ah, but not in this universe-”

The Librarian opened one eye.

“You suggestin' I nipped into some other universe to get married?” said Ridcully.

“No! I mean, you got married in that universe and not in this universe,” said Ponder.

“Did I? What? A proper ceremony and everything?”

“Yes!”

“Hmm.” Ridcully stroked his beard. “You sure?”

“Certain, Archchancellor.”

“My word! I never knew that.”

Ponder felt he was getting somewhere.

“So-”

“Yes?”

“Why don't I remember it?”

Ponder had been ready for this.

“Because the you in the other universe is different from the you here,” he said. “It was a different you that got married. He's probably settled down somewhere. He's probably a great-grandad by now.”

“He never writes, I know that,” said Ridcully “And the bastard never invited me to the wedding.”

“Who?”

“Him.”

“But he's you!”

“Is he? Huh! You'd think I'd think of me, wouldn't you? What a bastard!”

It wasn't that Ridcully was stupid. Truly stupid wizards have the life expectancy of a glass hammer. He had quite a powerful intellect, but it was powerful like a locomotive, and ran on rails and was therefore almost impossible to steer.

There are indeed such things as parallel universes, although parallel is hardly the right word - universes swoop and spiral around one another like some mad weaving machine or a squadron of Yossarians with middle-ear trouble.

And they branch. But, and this is important, not all the time. The universe doesn't much care if you tread on a butterfly. There are plenty more butterflies. Gods might note the fall of a sparrow but they don't make any effort to catch them.

Shoot the dictator and prevent the war? But the dictator is merely the tip of the whole festering boil of social pus from which dictators emerge; shoot one, and there'll be another one along in a minute. Shoot him too? Why not shoot everyone and invade Poland? In fifty years', thirty years', ten years' time the world will be very nearly back on its old course. History always has a great weight of inertia.

Almost always . . .

At circle time, when the walls between this and that are thinner, when there are all sorts of strange leakages

. . . Ah, then choices are made, then the universe can be sent careening down a different leg of the well-known Trousers of Time.

But there are also stagnant pools, universes cut off from past and future. They have to steal pasts and futures from other universes; their only hope is to batten on to the dynamic universes as they pass through the fragile period, as remora fish hang on to a passing shark. These are the parasite universes and, when the crop circles burst like raindrops, they have their chance . . .

* * *

Lancre castle was far bigger than it needed to be. It wasn't as if Lancre could have been bigger at one time; inhospitable mountains crowded it on three sides, and a more or less sheer drop occupied where the fourth side would have been if a sheer drop hadn't been there. As far as anyone knew, the mountains didn't belong to anyone. They were just mountains. The castle rambled everywhere. No one even knew how far the cellars went.

These days everyone lived in the turrets and halls near the gate.

“I mean, look at the crenellations,” said Magrat.

“What, m'm?”

“The cut-out bits on top of the walls. You could hold off an army here.”

“That's what a castle's for, isn't it, m'm?”

Magrat sighed. “Can we stop the 'm'm', please? It makes you sound uncertain.”

“Mm, m'm?”

“I mean, who is there to fight up here? Not even trolls could come over the mountains, and anyone coming up the road is asking for a rock on the head. Besides, you only have to cut down Lancre bridge.”

“Dunno, m'm. Kings've got to have castles, I s'pose.”

“Don't you ever wonder about anything, you stupid girl?”

“What good does that do, m'm?”

I called her a stupid girl, thought Magrat. Royalty is rubbing off on me.

“Oh, well,” she said, “where've we got to?”

“We're going to need two thousand yards of the blue chintz material with the little white flowers,” said Millie.

“And we haven't even measured half the windows yet,” said Magrat, rolling up the tape measure.

She looked down the length of the Long Gallery. The thing about it, the thing that made it so noticeable, the first thing anyone noticed about it, was that it was very long. It shared certain distinctive traits with the Great Hall and the Deep Dungeons. Its name was a perfectly accurate description. And it would be, as Nanny Ogg would say, a bugger to carpet.