Thud!

as the universe. But it has no real body and very little physical strength; it can cover a million dimensions in the blink of an eye but could barely make it across a room. It works through living creatures, especially ones it finds…amenable. It found you , Commander, a cauldron of anger, and in small, subtle ways it saw that you got it to this place.”
    “I believe him, sir,” said Angua quickly. “It was the one called up as a curse by one of the miners. Remember? The one who drew the sign in his own blood? On a locked door? And you—”
    “There was a door that stung when I touched it, I remember…” said Vimes. “Are you telling me that behind that door he—oh, no…”
    “He was already dead by then, sir, I’m positive about that,” said Angua quickly. “We couldn’t have saved him.”
    “Helmclever said—” Vimes began, and Bashfullsson must have seen the panic rising in his eyes, because he grabbed both his hands and spoke fast and urgently: “No! You didn’t kill him! You didn’t even touch him! You were afraid that if you did, I’d say you’d used force, remember?”
    “He dropped dead! How much force is that?” Vimes shouted. His voice echoed, and heads turned all across the cavern. “There was the symbol, wasn’t there?”
    “It’s true that the…creature tends to leave a, a signature on events, but you would have had to touch him! You did not ! You did not raise a hand! I think you would have resisted even then! Resisted and won! Do you hear me? Calm down. Calm down . He died of fear and guilt. You must realize that.”
    “What reason did he have to feel guilty?”
    “Every reason, for a dwarf. That mine bore down so heavily on him.” The grag turned to Angua. “Sergeant, could you get the commander some water? It’s as pure in these pools as anywhere in the world. Well, it is if you pick one without a body floating in it.”
    “Y’know, you could have avoided that last sentence?” said Vimes. He sat down on a rock. He could feel himself shaking now.
    “And then I got the damn thing here?” he managed.
    “Yes, Commander. And it got you here, too, I suspect. Cheery says she saw you drop into churning water half a mile from where we are now. Even a champion swimmer wouldn’t have survived that.”
    “I woke up on a beach—”
    “It got you there. It swam your body for you.”
    “But I was all knocked about!”
    “Oh, it wasn’t your friend , Commander. It needed to get you here in one piece. It didn’t have to be a good-looking piece. And then…you disappointed it, Commander. You disappointed it. Or, perhaps, impressed it. It’s hard to tell. You wouldn’t strike the helpless, you see. You resisted. I had the sergeant here bring you down because I was frightened that the struggle inside would rip your tendons from your bones.”
    “They were just frightened old men…”
    “And so, it appears to have let you go,” said the dwarf. “I wonder why? Historically, anyone subject to the Summoning Dark dies insane.”
    Vimes reached up and took a mug of water from Angua. It was teeth-aching cold and the best drink he’d ever tasted. And his mind worked fast, flying in emergency supplies of common sense, as human minds do, to construct a huge anchor in sanity and prove that what happened hadn’t really happened and, if it had happened, hadn’t happened much.
    It was all mystic, that’s what it was. Oh, it might all be true, but how could you ever tell? You had to stick to the things you can see. And you had to keep reminding yourself of that, too.
    Yeah, that was it. What had really happened, eh? A few signs? Well, anything can look like you want it to, if you’re worried and confused enough, yes? A sheep can look like a cow, right? Ha!
    As for the rest, well, Bashfullsson seemed a decent lad, but you didn’t have to buy into his worldview. Same with Mr. Shine. That sort of thing could spook you.
    He’d been wound up about Young Sam, and when he’d seen those devil guards, of course he’d gone for them. He hadn’t been getting much sleep lately. It seemed like every hour brought some new problem. The mind played funny tricks.
    Surviving the underground river? Easy. He must have kept himself afloat. There were a lot of things the body would rather do than die.
    There…some logical thought, and the mystic becomes…well, straightforward. You can stop feeling like some puppet and become a man with a purpose once again.
    He put down the empty mug and