Thud!

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,