Night, forever. But within it, a city, shadowy and only real in certain ways.

The entity cowered in its alley, where the mist was rising. This could not have happened!

Yet it had. The streets had filled with…things. Animals! Birds! Changing shape! Screaming and yelling! And, above it all, higher than the rooftops, a lamb rocking back and forth in great slow motions, thundering over the cobbles…

And then bars had come down, slamming down, and the entity had been thrown back.

But it had been so close! It had saved the creature, it was getting through, it was beginning to have control…and now this…

In the darkness of the inner city, above the rustle of the never-ending rain, it heard the sound of boots approaching.

A shape appeared in the mist.

It drew nearer.

Water cascaded off a metal helmet and an oiled leather cloak as the figure stopped and, entirely unconcerned, cupped its hand in front of its face and lit a cigar.

Then the match was dropped on the cobbles, where it hissed out, and the figure said: “What are you?”

The entity stirred, like an old fish in a deep pool. It was too tired to flee.

“I am the Summoning Dark.” It was not, in fact, a sound, but had it been, it would have been a hiss. “Who are you?”

“I am the Watchman.”

“They would have killed his family!” The darkness lunged, and met resistance. “Think of the deaths they have caused! Who are you to stop me?”

“He created me. Quis custodiet ipsos custodes? Who watches the watchmen? Me. I watch him. Always. You will not force him to murder for you.”

“What kind of human creates his own policeman?”

“One who fears the dark”

“And so he should,” said the entity, with satisfaction.

“Indeed. But I think you misunderstand. I am not here to keep darkness out. I’m here to keep it in.” There was a clink of metal as the shadowy watchman lifted a dark lantern and opened its little door. Orange light cut through the blackness. “Call me…the Guarding Dark. Imagine how strong I must be.”

The Summoning Dark backed desperately into the alley, but the light followed it, burning it.

“And now,” said the watchman, “get out of town.”

—and went down as a werewolf landed on his back.

Angua drooled. The hair along her spine stood out like a saw blade. Her lips curled back like a wave. Her growl was from the back of a haunted cave. All together, these told the brain of anything monkey-shaped that movement meant death. And that stillness, while it also meant death, didn’t mean immediate, this actual second, death, and was therefore the smart-monkey option.

Vimes didn’t move. The growl knotted his muscles. Terror was in control.

I salute you, said a thought that was not his, and he felt the sudden absence of something whose presence he had not noticed before. In the blackness behind his eyes, some dark fin swished and vanished.

He heard a whimper, and the weight on him disappeared. He rolled over and saw, fading in the middle of the air, a crude drawing of an eye with a tail. It dwindled into nothing, and the all-enveloping darkness slowly gave way to flames and the light of the vurms. Blood had been spilled; they were pouring down the walls. He felt…

A certain amount of time passed. Vimes jerked awake.

“I read it for him!” he said, mostly to reassure himself.

“You did, sir,” said the voice of Angua, behind him. “Very clearly, too. We were more than two hundred yards away. Well done, sir. We thought you ought to have a rest.”

“What have I done well?” said Vimes, trying to sit up. The movement filled his world with pain, but he managed a brief glimpse before slumping back.

There was a lot of smoke in the cave, but there were actual torches flickering here and there. And a great many dwarfs, some distance away, some sitting down, some standing around in groups.

“Why are there so many dwarfs here, Sergeant?” he asked, looking up at the cavern roof. “That is, why are there so many dwarfs here that aren’t actually trying to kill us?”

“They’re from the Low King, sir. We’re their prisoners…sort of…er…but not exactly…”

“Of Rhys? Bugger that!” said Vimes, trying to get to his feet again. “I saved his bloody life once!” He managed to get upright, but then the world pivoted around him, and he would have fallen if Angua hadn’t caught him and lowered him onto a rock. Well, at least he was sitting up now…

“Not exactly prisoners,” Angua said. “We can’t go anywhere. But since we wouldn’t know where to go even it we could go anywhere, it’s all a bit moot. Sorry I’m only in a shift, sir, you know how it is. The dwarfs have promised to fetch my gear. Er…it’s all gone political, sir. The dwarf in command seems a decent sort but he’s way out of his depth, so he’s sticking with what he knows, sir. And, er, he doesn’t know a lot. Do you remember anything about what happened? You’ve been out for a good twenty minutes.”

“Yes. There were…wooly lambs…” Vimes’s voice trailed into silence for a while. Somehow, what he’d just said took the ring of veracity and dropped it in a deep, deep hole. “There weren’t wooly lambs, right?” he asked hopelessly.

“I didn’t see any,” said Angua carefully. “I did see a striding, screaming, vengeful maniac, sir. But in a good way,” she added.

The internal Vimes looked at memories he didn’t remember from the first time around.

“I—” he began.

“Everything’s…sort of fine, sir,” said Angua quickly. “But come and see this. Bashfullsson said you ought to see everything.”

“Bashfullsson…he’s the know-it-all dwarf, right?” he said.

“Ah, it’s all coming back, sir,” said Angua. “Good. He was a bit worried about that.”

Vimes was steadier on his feet now, but his right arm hurt like hell, and all the other pains that the day had accumulated were coming back and waving. Angua carefully led him through puddles and across rocks as slippery as wet marble until they reached a stalagmite. It was about eight feet high.

It was a troll. It wasn’t a rock shaped like a troll, it was a troll. They only got stonier when they died, Vimes knew, but the lines of this one had been softened by the milky rock dripped on the troll’s head.

“But now look at this, sir,” said Angua, leading him on. “They were destroying them…”

There was another stalagmite, lying on its side in a pool. It had been smashed off at the base. And it was…a dwarf.

Dwarfs crumble after death, just like humans, but all the armor, mail, chains, and heavy leather mean there’s no great change to the eye of the casual observer. The flowing rock had covered it all in a glistening shroud.

Vimes straightened up and looked across the cavern. Shapes loomed in the gloom, all the way to the near wall, where the drip of ages had formed a perfect ivory waterfall, frozen in time.

“There are more?”

“About twenty, sir. Half of them had been smashed before you…arrived. Look at this one over here, sir. You can just make them out. They’re sitting back-to-back, sir.”

Vimes stared at the figures under the glaze, and shook his head. A dwarf and a troll, together, cemented in rock.

“Is there anything to eat?” he said. It wasn’t the most awe-inspired thing to say, but it came from the stomach, with feeling.

“Our rations got lost in the excitement, sir. But the dwarfs will share theirs. They aren’t unfriendly, sir. Just cautious.”

“Share? They have dwarf bread?”

“I’m afraid so, sir.”

“I thought it was illegal to give that to prisoners. I think I’ll wait, thanks. And now, Sergeant, you can tell me about the excitement.”