Night Watch

signal…
    O…O…O…
    Officer In Trouble. A brother is hurtin’.
    Vimes spun around. There was no one creeping up on him. He eased himself around the chimneys and there, tucked between another couple of stacks and out of sight of everyone except Vimes and the celestial Buggy, was Carcer.
    He was taking aim.
    Vimes turned his head to spot the target.
    Fifty yards away, Carrot was picking his way across the top of the University’s High Energy Magic Building.
    The bloody fool was never any good at concealment. Oh, he ducked and crept, and, against all logic, that made him more noticeable. He didn’t understand the art of thinking himself invisible. And there he was, furtively shlepping through the debris on the roof and looking as inconspicuous as a big duck in a small bathtub. And he’d come without backup.
    The fool…
    Carcer was aiming carefully. The roof of the HEMB was a maze of abandoned equipment and Carrot was moving along behind the raised platform that held the huge bronze spheres known throughout the city as the Wizards’ Balls, which discharged surplus magic if—or, more usually, when—experiments in the hall below fouled up. Carrot, screened by all that, was not making such a good target, after all.
    Vimes raised his crossbow.
    Thunder…rolled. It was the roll of a giant iron cube down the stairways of the gods, a crackling, thudding crash that tore the sky in half and shook the building.
    Carcer glanced up and saw Vimes.

    “Wotcha doin’, mifter?”
    Buggy didn’t budge from the telescope. A crowbar wouldn’t have separated him at this point.
    “Shut up, ye daft corbies!” he muttered.
    Both men below had fired, and both men had missed because they were trying to fire and dodge at the same time.
    Something hard prodded Buggy’s shoulder.
    “Wot’s happ’nin’ , mifter?” said the insistent voice.
    He turned. There were a dozen bedraggled ravens behind him, looking like little old men in ill-fitting black cloaks. They were Tower of Art birds. Hundreds of generations of living in a highly charged magical environment had raised the intelligence level of what had been bright creatures to begin with. But, although the ravens were intelligent, these weren’t hugely clever. They just had a more persistent kind of stupidity, as befitted birds for whom the exciting panorama of the city below was a kind of daytime TV.
    “Push off !” shouted Buggy and turned back to the telescope. There was Carcer, running, and Vimes running after him, and here came the hail …
    It turned the world white. It thudded around him and made his helmet ring. Hailstones as big as his head bounced on the stone and hit Buggy from underneath. Cursing and shielding his face with his arms, hammered all the time by shattering crystal balls, each one predicting a future of pain, he skidded and slid across the rolling ice. He reached an ivy-hung arch between two lesser turrets, where the heron had already taken refuge, and fell inside. Frozen shrapnel still ricocheted in and stung him, but at least he could see and breathe.
    A beak prodded him sharply in the back.
    “Wot’s happ’nin’ now, mifter?”

    Carcer landed heavily on the arch between the student hall and the main buildings, almost lost his footing on the tiles, and hesitated. An arrow from a watchman below grazed his leg.
    Vimes dropped down behind him, just as the hail hit.
    Cursing and slipping, one man followed the other across the arch. Carcer reached a mass of ivy that led up onto the roof of the Library and scrambled up it, scattering ice below.
    Vimes grabbed the ivy just as Carcer disappeared onto the flat roof. He looked around at a crash behind him, and saw Carrot trying to make his way along the wall from the High Energy Magic Building. The hail was forming a halo of ice fragments around him.
    “Stay there!” Vimes bellowed.
    Carrot’s reply was lost in the noise.
    Vimes waved his arms and then grabbed at the ivy as his foot slipped.
    “Bloody stay there !” he yelled. “That is an order! You’ll go over!”
    He turned and started up the wet, cold vines.
    The wind dropped, and the last few hailstones bounced off the roof.
    Vimes stopped a few feet from the top of the ivy, worked his feet into firm footholds in the ancient, knotted stems, and reached up for a decent hold.
    Then he thrust himself up, left hand ready, caught the boot that swung toward him, and carried on rising, pushing Carcer off balance. The man sprawled backward on the