Guards! Guards! (Discworld 8)

Carrot brought himself to attention like a barn being raised and stared straight ahead with a ferocious expression of acute obedience.

“Well done, that man,” said the Patrician thoughtfully, as Carrot strode stiffly away. “Carry on, Captain. And do come down heavily on any silly rumours about dragons, right?”

“Yes, sir,” said Captain Vimes.

“Goodman.”

The coach rattled off, the bodyguard running alongside.

Behind him, Captain Vimes was only vaguely aware of the sergeant yelling at the retreating Carrot to stop.

He was thinking.

He looked at the prints in the mud. He used his regulation pike, which he knew was exactly seven feet long, to measure their size and the distance between them. He whistled under his breath. Then, with considerable caution, he followed the alley around the corner; it led to a small, padlocked and dirt-encrusted door in the back of a timber warehouse.

There was something very wrong, he thought.

The prints come out of the alley, but they don't go in. And we don't often get any wading birds in the Ankh, mainly because the pollution would eat their legs away and anyway, it's easier for them to walk on the surface.

He looked up. A myriad washing lines criss-crossed the narrow rectangle of the sky as efficiently as a net.

So, he thought, something big and fiery came out of this alley but didn't come into it.

And the Patrician is very worried about it.

I've been told to forget about it.

He noticed something else at the side of the alley, and bent down and picked up a fresh, empty peanut shell.

He tossed it from hand to hand, staring at nothing.

Right now, he needed a drink. But perhaps it ought to wait.

...

The Librarian knuckled his way urgently along the dark aisles between the slumbering bookshelves.

The rooftops of the city belonged to him. Oh, assassins and thieves might make use of them, but he'd long ago found the forest of chimneys, buttresses, gargoyles and weathervanes a convenient and somehow comforting alternative to the streets.

At least, up until now.

It had seemed amusing and instructive to follow the Watch into the Shades, an urban jungle which held no fears for a 300-lb ape. But now the nightmare he had seen while brachiating across a dark alley would, if he had been human, have made him doubt the evidence of his own eyes.

As an ape, he had no doubts whatsoever about his eyes and believed them all the time.

Right now he wanted to concentrate them urgently on a book that might hold a clue. It was in a section no-one bothered with much these days; the books in there were not really magical. Dust lay accusingly on the floor.

Dust with footprints in it.

“Oook?” said the Librarian, in the warm gloom.

He proceeded cautiously now, realising with a sense of inevitability that the footprints seemed to have the same destination in mind as he did.

He turned a corner and there it was.

The section.

The bookcase.