Thud!

and run.
    “Yes, Commander?” said the curator, hurrying over. “Doesn’t Ladeah Sybil do the most exquisite —”
    “She’s very good, yes,” said Vimes. “Tell me…how did Rascal know all this stuff?”
    “There were many dwarf songs about it, and some troll stories. Oh, and some humans hwitnessed it.”
    “So Rascal could have read about it?”
    “Oh, yes. Apart from the fact that he put it in the wrong part of the valley, he’d got it down quite accurately.”
    Vimes didn’t take his gaze off the paper battle.
    “Does anyone know why he put it in the wrong place, then?” he said.
    “There are several theories. One is that he hwas deceived by the fact that the dead dwarfs hwere cremated at that end of the valley, but after the storm that hwas hwhere many of the bodies ended up. There was also a great deal of dead hwood for bonfires. But I believe he chose that end because the view is so much better. The mountains are so dramatic.”
    Vimes sat down, staring at the sketch, willing it to yield its secret.
    Everyone will know the secret in a few weeks, Mr. Shine had said. Why?
    “Sir Reynold, was anything going to happen to the painting in the next couple of weeks?” he said.
    “Oh, yes,” said the curator. “Hwe hwould have installed it in its new room.”
    “Anything special about that?”
    “I did tell your sergeant, Commander,” said the curator a little reproachfully. “It is circular. Rascal always intended it to be seen in the round, as it hwere. So that the viewer could be there.”
    And I’m nearly there, too, Vimes thought.
    “I think the cube told the dwarfs something about Koom Valley,” he said, in a faraway voice, because he felt as though he was already in the valley. “It told them that the place where it was found was important. Even Rascal thought it was important. They needed a map, and Rascal painted one, even if he didn’t know it. Fred?”
    “Yessir?”
    “The dwarfs weren’t bothered about damaging the bottom of the painting because it doesn’t contain anything important. It’s just people. People move around.”
    “But, hwith respect, Commander, so do all those boulders,” said Sir Reynold.
    “They don’t matter. No matter how much the valley has changed, this picture will work,” said Vimes. The glow of understanding lit his brain.
    “But even the rivers moved over the years, and any amount of boulders have rolled down from the mountains,” said Sir Reynold. “I’m told the area looks nothing like that now.”
    “Even so,” said Vimes, in the same dreamy voice, “this map will work for thousands of years. It doesn’t mark a rock or a hollow or a cave, it just marks a spot. I can pinpoint it. That is, if I had a pin.”
    “I have one!” Sir Reynold said triumphantly, reaching to his lapel. “I spotted it in the street yesterday, and of course hwe all know the old saying: ‘See a pin and pick it up, and all day long—’ ”
    “Yes, thank you,” said Vimes, taking it. He walked to the end of the table and picked up one end of the painting, and dragged it back down the length of the table, the heavy paper flapping after him.
    He pinned the two ends together, held up the circle he had made, and lowered it over his head.
    “The truth is in the mountains,” he said. “For years you’ve been looking at a line of mountains. It’s really a circle of mountains.”
    “But I knew that!” said Sir Reynold.
    “In a way, sir, but you probably didn’t understand it until now, yes? Rascal was standing somewhere important. ”
    “hWell, yes. But it hwas a cave, Commander. He specifically mentions a cave. That’s hwhy people have searched along the valley hwalls. The painting’s set right in the middle, near the river.”
    “Then there’s something we still don’t know!” said Vimes, annoyed that a big moment had so quickly become a small one. “I’ll find out what it is when I get there!”
    There. He’d said it. But he’d known that he was going to go, known for…how long? It seemed like forever, but had it seemed like forever yesterday? This afternoon? He could see the place in his mind’s eye. Vimes at Koom Valley! He could practically taste the air! He could hear the roaring of the river, which ran as cold as ice!
    “Sam—” Sybil began.
    “No, this has got to be sorted out,” Vimes said quickly. “I don’t care about the stupid secret! Those deep-downers murdered our dwarfs, remember? They think the painting is a map