At this time of year?-

-the glow in the sky over there is the Aurora Corealis, the hublights, where the magical field of the Discworld constantly discharges itself among the peaks of Cori Celesti, the central mountain. And at this time of year the sun rises over the desert in Ephebe and over the sea in Omnia, so keep the hublights on the left and the sunset glow behind you-

“Did you ever go to Cori Celesti?” said Brutha.

Om, who had been nodding off in the cold, woke up with a start.

“Huh?”

“It's where the gods live.”

“Hah! I could tell you stories,” said Om darkly.

“What?”

“Think they're so bloody elite!”

“You didn't live up there, then?”

“No. Got to be a thunder god or something. Got to have a whole parcel of worshipers to live on Nob Hill. Got to be an anthropomorphic personification, one of them things.”

“Not just a Great God, then?”

Well, this was the desert. And Brutha was going to die.

“May as well tell you,” muttered Om. “It's not as though we're going to survive . . . See, every god's a Great God to someone. I never wanted to be that great. A handful of tribes, a city or two. It's not much to ask, is it?”

“There's two million people in the empire,” said Brutha.

“Yeah. Pretty good, eh? Started off with nothing but a shepherd hearing voices in his head, ended up with two million people.”

“But you never did anything with them,” said Brutha.

“Like what?”

“Well . . . tell them not to kill one another, that sort of thing . . .”

“Never really given it much thought. Why should I tell them that?”

Brutha sought for something that would appeal to god psychology.

“Well, if people didn't kill one another, there'd be more people to believe in you?” he suggested.

“It's a point,” Om conceded. “Interesting point. Sneaky.”

Brutha walked along in silence. There was a glimmer of frost on the dunes.

“Have you ever heard”, he said, “of Ethics?”

“Somewhere in Howondaland, isn't it?”

“The Ephebians were very interested in it.”

“Probably thinking about invading.”

“They seemed to think about it a lot.”

“Long-term strategy, maybe.”

“I don't think it's a place, though. It's more to do with how people live.”

"What, lolling around all day while slaves do the real work? Take it from me, whenever you see a bunch of buggers puttering around talking about truth and beauty and the best way of attacking Ethics, you can bet your sandals it's because dozens of other poor buggers are doing all the real work around the place while those fellows are living like-

“-gods?” said Brutha.

There was a terrible silence.

“I was going to say kings,” said Om, reproachfully.

“They sound a bit like gods.”

“Kings,” said Om emphatically.

“Why do people need gods?” Brutha persisted.

“Oh, you've got to have gods,” said Om, in a hearty, no-?nonsense voice.

“But it's gods that need people,” said Brutha. “To do the believing. You said.”

Om hesitated. “Well, okay,” he said. “But people have got to believe in something. Yes? I mean, why else does it thunder?”

“Thunder,” said Brutha, his eyes glazing slightly, “I don't-”

“-is caused by clouds banging together; after the lightning stroke, there is a hole in the air, and thus the sound is engendered by the clouds rushing to fill the hole and colliding, in accordance with strict cumulodynamic principles.”

“Your voice goes funny when you're quoting,” said Om. “What does engendered mean?”

“I don't know. No one showed me a dictionary.”

“Anyway, that's just an explanation,” said Om. “It's not a reason.”

“My grandmother said thunder was caused by the Great God Om taking his sandals off,” said Brutha. “She was in a funny mood that day. Nearly smiled.”

“Metaphorically accurate,” said Om. “But I never did thundering. Demarcation, see. Bloody I've-got-a-big?-hammer Blind Io up on Nob Hill does all the thundering.”

“I thought you said there were hundreds of thunder gods,” said Brutha.

“Yeah. And he's all of 'em. Rationalization. A couple of tribes join up, they've both got thunder gods, right? And the gods kind of run together-you know how amoebas split?”

“No.”

“Well, it's like that, only the other way.”

“I still don't see how one god can be a hundred thunder gods. They all look different . . .”

“False noses.”

“What?”

“And different voices. I happen to know Io's got seventy different hammers. Not common knowledge, that. And it's just the same with mother goddesses. There's only one of 'em. She just got a lot of wigs and of course it's amazing what you can do with a padded bra.”

There was absolute silence in the desert. The stars, smeared slightly by high-altitude moisture, were tiny, motionless rosettes.

Away toward what the Church called the Top Pole, and which Brutha was coming to think of as the Hub, the sky flickered.

Brutha put Om down, and laid Vorbis on the sand.

Absolute silence.

Nothing for miles, except what he had brought with him. This must have been how the prophets felt, when they went into the desert to find . . . whatever it was they found, and talk to . . . whoever they talked to.

He heard Om, slightly peevish, say: “People've got to believe in something. Might as well be gods. What else is there?”

Brutha laughed.

“You know,” he said, “I don't think I believe in anything any more.”

“Except me!”

“Oh, I know you exist,” said Brutha. He felt Om relax a little. “There's something about tortoises. Tortoises I can believe in. They seem to have a lot of existence in one place. It's gods in general I'm having difficulty with.”

“Look, if people stop believing in gods, they'll believe in anything,” said Om. “They'll believe in young Urn's steam ball. Anything at all.”

“Hmm.”

A green glow in the sky indicated that the light of dawn was chasing frantically after its sun.

Vorbis groaned.

“I don't know why he won't wake up,” said Brutha. “I can't find any broken bones.”

“How do you know?”

“One of the Ephebian scrolls was all about bones. Can't you do anything for him?”

“Why?”

“You're a god.”

“Well, yes. If I was strong enough, I could probably strike him with lightning.”

“I thought to did the lightning.”

“No, just the thunder. You're allowed to do as much lightning as you like but you have to contract for the thundering.”

Now the horizon was a broad golden band.

“How about rain?” said Brutha. “How about something useful?”

A line of silver appeared at the bottom of the gold. Sunlight was racing towards Brutha.

“That was a very hurtful remark,” said the tortoise. “A remark calculated to wound.”

In the rapidly growing light Brutha saw one of the rock islands a little way off. Its sand-blasted pillars offered nothing but shade, but shade, always available in large quantities in the depths of the Citadel, was now in short supply here.

“Caves?” said Brutha.

“Snakes.”

“But still caves?”

“In conjunction with snakes.”

“Poisonous snakes?”

“Guess.”

The Unnamed Boat clipped along gently, the wind filling Urn's robe attached to a mast made out of bits of the sphere's framework bound together with Simony's sandal thongs.

“I think I know what went wrong,” said Urn. “A mere overspeed problem.”

“Overspeed? We left the water!” said Simony.

“It needs some sort of governor device,” said Urn, scratching a design on the side of the boat. “Something that'd open the valve if there was too much steam. I think I could do something with a pair of revolving balls.”

“It's funny you should say that,” said Didactylos. "When I felt us leave the water and the sphere exploded I distinctly felt my-

“That bloody thing nearly killed us!” said Simony.

“So the next one will be better,” said Urn, cheerfully. He scanned the distant coastline.

“Why don't we land somewhere along here?” he said.

“The desert coast?” said Simony. “What for? Nothing to eat, nothing to drink, easy to lose your way. Omnia's the only destination in this wind. We can land this side of the city. I know people. And those people know people. All across Omnia, there's people who know people. People who believe in the Turtle.”

“You know, I never meant for people to believe in the Turtle,” said Didactylos unhappily. “It's just a big turtle. It just exists. Things just happen that way. I don't think the Turtle gives a damn. I just thought it might be a good idea to write things down and explain things a bit.”

“People sat up all night, on guard, while other peo?ple made copies,” said Simony, ignoring him. “Pass?ing them from hand to hand! Everyone making a copy and passing it on! Like a fire spreading underground!”

“Would this be lots of copies?” said Didactylos cautiously.

“Hundreds! Thousands!”

“I suppose it's too late to ask for, say, a five per cent royalty?” said Didactylos, looking hopeful for a moment. “No. Probably out of the question, I expect. No. Forget I even asked.”

A few flying fish zipped out of the waves, pursued by a dolphin.

“Can't help feeling a bit sorry for that young Brutha,” said Didactylos.

“Priests are expendable,” said Simony. “There's too many of them.”

“He had all our books,” said Urn.

“He'll probably float with all that knowledge in him,” said Didactylos.

“He was mad, anyway,” said Simony. “I saw him whispering to that tortoise.”

“I wish we still had it. There's good eating on one of those things,” said Didactylos.

It wasn't much of a cave, just a deep hollow carved by the endless desert winds and, a long time ago, even by water. But it was enough.

Brutha knelt on the stony floor and raised the rock over his head.

There was a buzzing in his ears and his eyeballs felt as though they were set in sand. No water since sunset and no food for a hundred years. He had to do it.

“I'm sorry,” he said, and brought the rock down.

The snake had been watching him intently but in its early-morning torpor it was too slow to dodge. The cracking noise was a sound that Brutha knew his con?science would replay to him, over and over again.

“Good,” said Om, beside him. “Now skin it, and don't waste the juice. Save the skin, too.”

“I didn't want to do it,” said Brutha.

“Look at it this way,” said Om, “if you'd walked in the cave without me to warn you, you'd be lying on the floor now with a foot the size of a wardrobe. Do unto others before they do unto you.”