Strata

size of a world, and then I think of all the things that can go wrong with a ship. I don’t gloat, I tremble with fear. And rage.’
    She stood up and stomped across the room to ease the cramp in her muscles. It had been along session, a subterranean travelogue of disc machinery. The earthquake machines stuck in her memory. All that ingenuity, to reproduce what any half-sized world did naturally. And the demons … well, at least she’d put a stop to the demons.
    There was a click as Marco undid his straps and leapt towards the horseshoe panel. He peered at the screen, then glared out of the cabin.
    ‘Where the hell is it? It’s gone off the screen. What was it, Kin? The blip was bigger than a—’
    Whump
. Beyond the windows the seashore exploded into a sandstorm.
    Marco craned his head and looked up. Darkness filled the cabin as the sun was eclipsed.
    Whump
.
    Marco looked up at talons dropping out of the sky when the impossible bird stooped. Talons big enough to grip a ship. He made a small noise in his throat and took a dive in the direction of his couch.
    Whump. Scrabble. Whump. Whumpwhump. Whumpwhump
.
    The ship creaked as the claws took it gently. Then it bounded upward in a series of bone-shaking jerks.
    The dome of the hub swung crazily below, and whirled away. The disc dropped after it, teetering across the sky until it was a blue and ochre wall. It paused there, then plunged backunder the ship to loom for a moment on the other side. Whump .
    Kin concentrated on the view above, to take her mind off the lurching, jerking universe. The talons all but covered the roof port, but she got occasional glimpses of the huge white wings, beating now with the slow rhythm of a tide.
    Sound filled the cabin. It began in the painful ultrasonic, swooping down the scale like wet fingers being dragged across the windows of the soul.
    High above the disc the roc stood on the air and sang.
    There would be no more demons. She could see why there had been demons, demons were an idea that worked, but there would be no more.
    The ones Kin had met had been almost human compared with some of the things force-bred in the quiet green laboratories under the hub. They policed the disc, haunted the hidden air vents and access shafts to the machinery, chased the venturesome from the rim. Occasionally they kidnapped a new Chairman, for the Committee.
    The Chairmen. Kin stared at the blank screen, then glanced up at the hovering direct-link helmet over the chair. She had no intention of trying it for size, and the Computers hadn’t pressed her, but they had shown her how it was used.
    The Computers ran the disc. They adjusted its tides, circulated its waters, counted its falling sparrows, toiled and spun for the lilies of its fields. But the disc’s builders had constructed them as servile mechanisms, lest the disc become too mechanical. A human had to tell them what to do.
    In the seventy thousand years of the disc’s history there had been two hundred and eighty Chairmen, thrust in terror under the helmet. It gave them cold new knowledge.
    Kin said she didn’t believe it.
    ‘You couldn’t take a Neolithic farmer and turn him into a planetary engineer,’ she protested.
    WE COULD. THE DISC BUILDERS CONSTRUCTED US CLEVERLY .
    ‘You won’t even tell me about the builders!’
    The screen went blank.
    Whump
. Kin gripped the edges of the couch.
Whump
. The roc didn’t fly, it simply bullied its way through the upper air, shovelling it aside with a sneer.
    Talking was difficult when g-forces slapped and banged with a horrible rhythm. Silver managed it with the least discomfort.
    ‘I don’t believe it either,’ she said. ‘I can see what a device like the Disc would need.’
Whump
. ‘Needs a sapient caretaker. No machines could handle all the problems that might crop.’
Whump
. ‘Might crop up. But unless the creaturewas already a technical sophisticate, he would simply become mad.’
    Kin braced herself for the next wingbeat. It didn’t come. Beyond the window she could see the roc’s wing outstretched, the tips of the huge feathers vibrating in the slipstream. The bird was starting its glide.
    Half the Disc was spread before the canted cabin. Kin rolled out of her couch and swayed across the trembling deck until she could grasp a bulkhead.
    The world was a bowl of jewels flung across the sky. Ahead, wearing the setting sun like the gemstone on a ring, was the Rim Ocean.
    Roc slid on down the sky, staring at the sun with