' 'S funny, but... I see what you mean.'

'Makes sense, right?'

'Makes sense, yeah. Thing is...'

'What?'

'I just hope it never goes plop.'

But this is the Discworld, which has not only the turtle but also the four giant elephants on which the wide, slowly turning wheel of the world revolves.

There is the Circle Sea, approximately halfway between the Hub and the Rim. Around it are those countries which, according to History, constitute the civilized world, i.e., a world that can support histor-ians: Ephebe, Tsort, Omnia, Klatch and the sprawling city state of Ankh-Morpork.

This is a story that starts somewhere else, where a man is lying on a raft in a blue lagoon under a sunny sky. His head is resting on his arms. He is happy - in his case, a mental state so rare as to be almost unprecedented. He is whistling an amiable little tune, and dangling his feet in the crystal clear water.

They're pink feet with ten toes that look like little piggy-wiggies.

From the point of view of a shark, skimming over the reef, they look like lunch, dinner and tea.

It was, as always, a matter of protocol. Of discretion. Of careful etiquette. Of, ultimately, alcohol. Or at least the illusion of alcohol.

Lord Vetinari, as supreme ruler of Ankh-Morpork, could in theory summon the Archchancellor of Unseen University to his presence and, indeed, have him executed if he failed to obey.

On the other hand Mustrum Ridcully, as head of the college of wizards, had made it clear in polite but firm ways that he could turn him into a small amphibian and, indeed, start jumping around the room on a pogo stick.

Alcohol bridged the diplomatic gap nicely. Sometimes Lord Vetinari invited the Archchancellor to the palace for a convivial drink. And of course the Archchancellor went, because it would be bad manners not to. And everyone understood the position, and everyone was on their best behaviour, and thus civil unrest and slime on the carpet were averted.

It was a beautiful afternoon. Lord Vetinari was sitting in the palace gardens, watching the butterflies with an expression of mild annoyance. He found something very slightly offensive about the way they just fluttered around enjoying themselves in an unprofitable way.

He looked up.

'Ah, Archchancellor,' he said. 'So good to see you. Do sit down. I trust you are well?'

'Yes indeed,' said Mustrum Ridcully. 'And yourself? You are in good health?'

'Never better. The weather, I see, has turned out nice again.'

'I thought yesterday was particularly fine, certainly.'

'Tomorrow, I am told, could well be even better.'

'We could certainly do with a fine spell.'

'Yes, indeed.'

'Yes.'

'Ah...'

'Certainly.'

They watched the butterflies. A butler brought long, cool drinks.

'What is it they actually do with the flowers?' said Lord Vetinari.

'What?'

The Patrician shrugged. 'Never mind. It was not at all important. But - since you are here, Archchancellor, having dropped by on your way to something infinitely more important, I am sure, most kind - I wonder if you could tell me: who is the Great Wizard?'

Ridcully considered this.

'The Dean, possibly,' he said. 'He must be all of twenty stone.'

'Somehow I feel that is not perhaps the right answer,' said Lord Vetinari. 'I suspect from context that "great" means superior.'

'Not the Dean, then,' said Ridcully.

Lord Vetinari tried to recollect the faculty of Unseen University. The mental picture that emerged was of a small range of foothills in pointy hats.

'The context does not, I feel, suggest the Dean,' he said.

'Er... what context would this be?' said Ridcully.

The Patrician picked up his walking stick.

'Come this way,' he said. 'I suppose you had better see for yourself. It is very vexing.'

Ridcully looked around with interest as he followed Lord Vetinari. He did not often have a chance to see the gardens, which had been written up in the 'How Not To Do It' section of gardening manuals everywhere.

They had been laid out, and a truer phrase was never used, by the renowned or at least notorious landscape gardener and all round inventor 'Bloody Stupid' Johnson, whose absent-mindedness and blindness to elementary mathematics made every step a walk with danger. His genius... well, as far as Ridcully understood it, his genius was exactly the opposite of whatever kind of genius it was that built earthworks that tapped the secret yet beneficent forces of the leylines.

No-one was quite certain what forces Bloody Stupid's designs tapped, but the chiming sundial frequently exploded, the crazy paving had committed suicide and the cast iron garden furniture was known so have melted on three occasions.

The Patrician led the way through a gate and into something like a dovecot. A creaking wooden stairway led around the inside. A few of Ankh-Morpork's indestructible feral pigeons muttered and sniggered in the shadows.

'What's this?' said Ridcully, as the stairs groaned under him.

The Patrician took a key out of his pocket. 'I have always understood that Mr Johnson originally planned this to be a beehive,' he said. 'However, in the absence of bees ten feet long we have found... other uses.'

He unlocked a door to a wide, square room with a big unglazed window in each wall. Each rectangle was surrounded by a wooden arrangement to which was affixed a bell on a spring. It was apparent that anything large enough, entering by one of the windows, would cause the bell to ring.

In the centre of the room, standing on a table, was the largest bird Ridcully had ever seen. It turned and fixed him with a beady yellow eye.

The Patrician reached into a pocket and took out a jar of anchovies. 'This one caught us rather unexpectedly,' he said. 'It must be almost ten years since a message last arrived. We used to keep a few fresh mackerel on ice.'

'Isn't that a Pointless Albatross?' said Ridcully.

'Indeed,' said Lord Vetinari. 'And a highly trained one. It will return this evening. Six thousand miles on one jar of anchovies and a bottle of fish paste my clerk Drumknott found in the kitchens. Amazing.'

'I'm sorry?' said Ridcully. 'Return to where?'

Lord Vetinari turned to face him.

'Not, let me make it clear, to the Counterweight Continent,' he said. 'This is not one of those birds the Agatean Empire uses for its message services. It is a well-known fact that we have no contact with that mysterious land. And this bird is not the first to arrive here for many years, and it did not bring a strange and puzzling message. Do I make myself clear?'

'No.'

'Good.'

'This is not an albatross?'

The Patrician smiled. 'Ah, I can see you're getting the hang of it.'

Mustrum Ridcully, though possessed of a large and efficient brain, was not at home with duplicity. He looked at the long vicious beak.

'Looks like a bloody albatross to me,' he said. 'And you just said it was. I said, isn't that a—'

The Patrician waved a hand irritably. 'Leaving aside our ornithological studies,' he said, 'the point is that this bird had, in its message pouch, the following piece of paper—'

'You mean did not have the following piece of paper?' said Ridcully, struggling for a grip.

'Ah, yes. Of course, that is what I mean. And this isn't it. Observe.'

He handed a single small sheet to the Arch-chacellor.

'Looks like paintin',' said Ridcully.

'Those are Agatean pictograms,' said the Patrician.

'You mean they're not Agatean pictograms?'

'Yes, yes, certainly,' sighed the Patrician, 'I can see you are well alongside the essential business of diplomacy. Now... your views, please.'

'Looks like slosh, slosh, slosh, slosh, Wizzard,' said Ridcully.