Guards! Guards!

stars came out.
    Colon, Nobby and Carrot were also on the roof. Colon was sulking because Vimes had forbidden him to use his bow and arrow.
    These weren’t encouraged in the city, since the heft and throw of a longbow’s arrow could send it through an innocent bystander a hundred yards away rather than the innocent bystander at whom it was aimed.
    “That’s right,” said Carrot, “the Projectile Weapons (Civic Safety) Act, 1634.”
    “Don’t you keep on quoting all that sort of stuff,” snapped Colon. “We don’t have any of them laws anymore! That’s all old stuff! It’s all more wossname now. Pragmatic.”
    “Law or no law,” said Vimes, “ I say put it away.”
    “But Captain, I was a dab hand at this!” protested Colon. “Anyway,” he added peevishly, “a lot of other people have got them.”
    That was true enough. Neighboring rooftops bristled like hedgehogs. If the wretched thing turned up, it was going to think it was flying through solid wood with slots in it. You could almost feel sorry for it.
    “I said put it away,” said Vimes. “I’m not having my guards shooting citizens. So put it away.”
    “That’s very true,” said Carrot. “We’re here to protect and to serve, aren’t we, Captain.”
    Vimes gave him a sidelong look. “Er,” he said. “Yeah. Yes. That’s right.”
    On the roof of her house on the hill, Lady Ramkin adjusted a rather inadequate folding chair on the roof, arranged the telescope, coffee flask and sandwiches on the parapet in front of her, and settled down to wait. She had a notebook on her knee.
    Half an hour went by. Hails of arrows greeted a passing cloud, several unfortunate bats, and the rising moon.
    “Bugger this for a game of soldiers,” said Nobby, eventually. “It’s been scared off.”
    Sgt. Colon lowered his pike. “Looks like it,” he conceded.
    “And it’s getting chilly up here,” said Carrot. He politely nudged Captain Vimes, who was slumped against the chimney, staring moodily into space.
    “Maybe we ought to be getting down, sir?” he said. “Lots of people are.”
    “Hmm?” said Vimes, without moving his head.
    “Could be coming onto rain, too,” said Carrot.
    Vimes said nothing. For some minutes he had been watching the Tower of Art, which was the center of Unseen University and reputedly the oldest building in the city. It was certainly the tallest. Time, weather and indifferent repairs had given it a gnarled appearance, like a tree that has seen too many thunderstorms.
    He was trying to remember its shape. As is the case with many things that are totally familiar, he hadn’t really looked at it for years. Now he was trying to convince himself that the forest of little turrets and crenellations at its top looked just the same tonight as they had done yesterday.
    It was giving him some difficulty.
    Without taking his eyes off it, he grabbed Sgt. Colon’s shoulder and gently pointed him in the right direction.
    He said, “Can you see anything odd about the top of the tower?”
    Colon stared up for a while, and then laughed nervously. “Well, it looks like there’s a dragon sitting on it, doesn’t it?”
    “Yes. That’s what I thought.”
    “Only, only, only when you sort of look properly, you can see it’s just made up out of shadows and clumps of ivy and that. I mean, if you half-close one eye, it looks like two old women and a wheelbarrow.”
    Vimes tried this. “Nope,” he said. “It still looks like a dragon. A huge one. Sort of hunched up, and looking down. Look, you can see its wings folded up.”
    “Beg pardon, sir. That’s just a broken turret giving the effect.”
    They watched it for a while.
    Then Vimes said, “Tell me, Sergeant—I ask in a spirit of pure inquiry—what do you think’s causing the effect of a pair of huge wings unfurling?”
    Colon swallowed.
    “I think that’s caused by a pair of huge wings, sir,” he said.
    “Spot on, Sergeant.”
    The dragon dropped. It wasn’t a swoop. It simply kicked away from the top of the tower and half-fell, half-flew straight downward, disappearing from view behind the University buildings.
    Vimes caught himself listening for the thump.
    And then the dragon was in view again, moving like an arrow, moving like a shooting star, moving like something that has somehow turned a thirty-two feet per second plummet into an unstoppable upward swoop. It glided over the rooftops at little more than head height, all the more horrible because of the