Guards! Guards!

There was also the sound of someone snoring.

The light from the shelves didn't so much illuminate as highlight the darkness, but by its violet flicker a watcher might just have identified an ancient and battered desk right under the central dome.

The snoring was coming from underneath it, where a piece of tattered blanket barely covered what looked like a heap of sandbags but was in fact an adult male orangutan.

It was the Librarian.

Not many people these days remarked upon the fact that he was an ape. The change had been brought about by a magical accident, always a possibility where so many powerful books are kept together, and he was considered to have got off lightly. After all, he was still basically the same shape. And he had been allowed to keep his job, which he was rather good at, although 'allowed' is not really the right word. It was the way he could roll his upper lip back to reveal more incredibly yellow teeth than any other mouth the University Council had ever seen before that somehow made sure the matter was never really raised.

But now there was another sound, the alien sound of a door creaking open. Footsteps padded across the floor and disappeared amongst the clustering shelves. The books rustled indignantly, and some of the larger grimoires rattled their chains.

The Librarian slept on, lulled by the whispering of the rain.

In the embrace of his gutter, half a mile away, Captain Vimes of the Night Watch opened his mouth and started to sing.

Now a black-robed figure scurried through the midnight streets, ducking from doorway to doorway, and reached a grim and forbidding portal. No mere doorway got that grim without effort, one felt. It looked as though the architect had been called in and given specific instructions. We want something eldritch in dark oak, he'd been told. So put an unpleasant gargoyle thing over the archway, give it a slam like the footfall of a giant and make it clear to everyone, in fact, that this isn't the kind of door that goes 'ding-dong' when you press the bell.

The figure rapped a complex code on the dark woodwork. A tiny barred hatch opened and one suspicious eye peered out.

' 'The significant owl hoots in the night,' ' said the visitor, trying to wring the rainwater out of its robe.

' 'Yet many grey lords go sadly to the masterless men,' ' intoned a voice on the other side of the grille.

' 'Hooray, horray for the spinster's sister's daughter,' ' countered the dripping figure.

' 'To the axeman, all supplicants are the same height.' '

' 'Yet verily, the rose is within the thorn.' '

' 'The good mother makes bean soup for the errant boy,' ' said the voice behind the door.

There was a pause, broken only by the sound of the rain. Then the visitor said, 'What?'

' 'The good mother makes bean soup for the errant boy.' '

There was another, longer pause. Then the damp figure said, 'Are you sure the ill-built tower doesn't tremble mightily at a butterfly's passage?'

'Nope. Bean soup it is. I'm sorry.'

The rain hissed down relentlessly in the embarrassed silence.

'What about the caged whale?' said the soaking visitor, trying to squeeze into what little shelter the dread portal offered.

'What about it?'

'It should know nothing of the mighty deeps, if you must know.'

'Oh, the caged whale. You want the Elucidated Brethren of the Ebon Night. Three doors down.'