Guards! Guards! (Discworld 8)

That seemed to be the only effect, except that something round the back of the house started to howl. Some things.

It started to rain again. After a while Vimes felt the dignity of his position and cautiously edged around the building, keeping well back in case anything else collapsed.

He reached a heavy wooden gate in a heavy wooden wall. In contrast with the general decrepitude of the rest of the place, it seemed comparatively new and very solid.

He knocked. This caused another fusillade of strange whistling noises.

The door opened. Something dreadful loomed over him.

“Ah, good man. Do you know anything about mating?” it boomed.

...

It was quiet and warm in the Watch House. Carrot listened to the hissing of sand in the hourglass and concentrated on buffing up his breastplate. Centuries of tarnish had given up under his cheerful onslaught. It gleamed.

You knew where you were with a shiny breastplate. The strangeness of the city, where they had all these laws and concentrated on ignoring them, was too much for him. But a shiny breastplate was a breastplate well shined.

The door opened. He peered across the top of the ancient desk. There was no-one there.

He tried a few more industrious rubs.

There was the vague sound of someone who had got fed up with waiting. Two purple-fingernailed hands grasped the edge of the desk, and the Librarian's face rose slowly into view like an early-morning coconut.

“Oook,” he said.

Carrot stared. It had been explained to him carefully that, contrary to appearances, laws governing the animal kingdom did not apply to the Librarian. On the other hand, the Librarian himself was never very interested in obeying the laws governing the human kingdom, either. He was one of those little anomalies you have to build around.

“Hallo,” said Carrot uncertainly. (“Don't call him 'boy' or pat him, that always gets him annoyed.”)

“Oook.”

The Librarian prodded the desk with a long, many-jointed finger.

“What?”

“Oook. ”

“Sorry?”

The Librarian rolled his eyes. It was strange, he felt, that so-called intelligent dogs, horses and dolphins never had any difficulty indicating to humans the vital news of the moment, e.g., that the three children were lost in the cave, or the train was about to take the line leading to the bridge that had been washed away or similar, while he, only a handful of chromosomes away from wearing a vest, found it difficult to persuade the average human to come in out of the rain. You just couldn't talk to some people.

“Oook!” he said, and beckoned.

“I can't leave the office,” said Carrot. “I've had Orders.”

The Librarian's upper lip rolled back like a blind.

“Is that a smile?” said Carrot. The Librarian shook his head.

“Someone hasn't committed a crime, have they?” said Carrot.

“Oook.”

“A bad crime?”

“Oook!”

“Like murder?”