There was a crowd of dwarfs milling around outside the Yard. They did not look belligerent—that is to say, any more than a species the members of which, by custom and practice, wear a big heavy helmet, mail, iron boots, and carry an axe all the time can fail to look belligerent—but they did look lost and bewildered and unsure why they were there.

Vimes got Willikins to drive in through the coach arch and take the bodies of the attackers down to Igor, who knew about things like people dying with green mouths.

Sybil, Purity, and Young Sam were hustled away to a clean office. Interesting thing, Vimes thought as he watched Cheery and a group of dwarf officers fuss over the child: even now—in fact, especially now, given the way the tension had made everyone revert to old certainties—he wasn’t sure how many female dwarf officers he had. It was a brave female dwarf who advertised the fact, in a society where the wearing of even a decent, floor-length leather-and-chain-mail dress instead of leggings positioned you on the moral map at the far side of Tawneee and her hardworking coworkers at the PussyCat Club. But introduce a gurgling kid into the room, and you could spot them instantly, for all their fearsome clang and beards you could lose a rat in.

Carrot pushed his way through the crowd and saluted.

“A lot’s been happening, sir!”

“My word, has it?” said Vimes, with manic brightness.

“Yessir. Everyone was pretty…angry when we brought the dead dwarfs up, and what with one thing and another, opening the big door in Treacle Street was pretty popular. All the deep-downers have gone, except one—”

“That’d be Helmclever,” said Vimes, heading for his office.

Carrot looked surprised. “That’s right, sir. He’s in a cell. I’d like you to have a look at him, if you don’t mind. He was crying and moaning and trembling in a corner, with lit candles all ’round him.”

“More candles? Afraid of the dark?” Vimes suggested.

“Could be, sir. Igor says the trouble’s in his head.”

“Don’t let Igor try to give him a new one!” said Vimes quickly. “I’ll go down there as soon as I can.”

“I’ve tried talking to him, but he just looks blank, sir. How did you know he was the one we found?”

“I’ve got some edges and some bits that are an interesting shape,” said Vimes, sitting down at his desk. When Carrot looked blank, he went on: “Of the jigsaw puzzle, Captain. But there are lots of bits of sky. However, I think I might be nearly there, because I think I’ve been handed a corner. What talks underground?”

“Sir?”

“You know, the dwarfs were listening for something underground? You wondered if someone was trapped, right? But is there…I don’t know…something dwarf-made that talks?”

Carrot’s brow wrinkled.

“You’re not talking about a cube, are you, sir?”

“I don’t know. Am I? You tell me!”

“The deep-downers have some in their mine, sir, but I’m sure there’s none buried here. They’re generally found in hard rocks. Anyway, you wouldn’t listen for one. I’ve never heard of them talking when they are found. Some dwarfs have spent years learning how to use just one of them!”

“Good! Now: What Is A Cube?” said Vimes, glancing at his in-tray. Oh, good. There weren’t any memos from A. E. Pessimal.

“It’s, um…it’s like a book, sir. Which talks. A bit like your Gooseberry, I suppose. Most of them contain interpretations of dwarf lore by ancient lawmasters. It’s very old…magic, I suppose.”

“Suppose?” said Vimes.

“Well, technomantic Devices look like things that are built, you know, out of—”

“Captain, you’ve lost me again. What are Devices and why do you pronounce the capital D?”

“Cubes are a type of Device, sir. No one knows who made them or for what original purpose. They might be older than the world. They’ve been found in volcanoes and the deepest rocks. The deep-downers have most of them. They come in all sorts of—”

“Hold on, you mean that when they’re dug up, there’s dwarf voices from millions of years ago? Surely dwarfs haven’t been—”

“No, sir. Dwarfs put them on later. I’m not too well up on this. I think when they’re first found, they mostly have natural noises, like moving water or birdsong or rocks moving, that sort of thing. The grags found out how to get rid of those to make room for words, I think. I did hear about one that was the sounds of a forest. Ten million years of sounds, in a cube less than two inches across.”

“And they’re valuable, these things?”

“Unbelievably valuable, especially the cubes. Worth mining through a mountain of granite, as we say…er, that’s a dwarf ‘we,’ not a copper ‘we,’ sir.”

“So, digging through a few thousand of tons of Ankh-Morpork muck would be worth it, then?”

“For a cube? Yes! Is that what all this is about? But how would it get here? The average dwarf might never see one in his whole life. Only grags and great chieftains use them! And why would it be talking? All dwarf ones can only be brought to life by a key word!”

“Search me. What do they look like? Apart from being cubical, I assume?”

“I’ve only ever seen a few, sir. They’re, oh, up to six inches on a side, look like old bronze, and they glitter.”

“Green and blue?” Said Vimes sharply.

“Yes, sir! They had a few in the mine in Treacle Street.”

“I think I saw them,” said Vimes. “And I think they’ve got one more. Voices from the past, eh? How come I’ve never heard of them before?”

Carrot hesitated. “You’re a very busy man, sir. You can’t know everything.”

Vimes detected just a soupçon of a smidgen of a reproach there.

“Are you saying I’m a man of narrow horizons, Captain?”

“Oh no, sir. You’re interested in every aspect of police work and criminology.”

Sometimes it was impossible to read Captain Carrot’s face. Vimes didn’t bother to try.

“I’m missing something,” he said. “But this is about Koom Valley, I know it. Look, what is the secret of Koom Valley?”

“I don’t know, sir. I don’t think there is one. I suppose the big secret would be which side attacked first. You know, sir, both sides say they were ambushed by the other side.”

“Does that sound very interesting to you?” said Vimes. “Would it matter much now?”

“Who started it all? I should say so, sir!” said Carrot.

“But I thought they’d been scrapping since time began?”

“Yes. But Koom Valley was the first official one, sir.”

“Who won?” said Vimes.

“Sir?”

“It’s not a difficult question, is it? Who won the first Battle of Koom Valley?”

“I suppose you could say it was rained off, sir,” said Carrot.

“They stopped a grudge march like that because of a bit of rain?”

“For a lot of rain, sir. A thunderstorm just sat there in the mountains above it. There were flash floods, full of boulders. The fighters were knocked off their feet and washed away, some were struck by lightning—”

“It quite ruined the whole day,” said Vimes. “All right, Captain, do we have any idea where the bastards have gone?”

“They had an escape tunnel—”

“I bet they did!”

“—and collapsed it after them. I’ve got men digging—”

“Stand them down. They could be in a safe house, they could have got out in a cart, hell, they could all be wearing helmets and chain mail and passing for city dwarfs. Enough of that. We’ve been running people ragged. Let them go for now. I think we’ll be able to find them again.”

“Yes, sir. The grags left so fast, sir, that they left some other Devices. I have secured them for the city. They must have been very frightened. They just took the cubes and ran. Are you all right, sir? You look a bit flustered.”

“Actually, Captain, I feel inexplicably cheerful. Would you like to hear how my day went?”