Shilly dropped the subject, knowing it would take more than words to convince Chu. The young flyer turned her attention forward, closing herself off to further conversation.

Banner still twisted to the rear, and Shilly realised that she was looking at something behind the buggy. At the same time, Tom eased off on the accelerator. Shilly turned to look too, fearing that a new man'kin threat had appeared. The truth was much less exotic. The first bus had fallen behind, allowing the second to overtake. It was difficult to see what was going on through the dust the buggies kicked up, but she could make out Marmion waving impatiently for them to continue. Maybe, she thought, they had wanted Highson safe in the middle of the convoy rather than at the end. Or perhaps she was just being charitable, and Marmion was worried about no other skin than his own.

Banner nodded and Tom increased their speed. They continued on across the bottom of the Divide, leaving Sal and Skender far behind.

The Ruin.

*Put behind you all thoughts of the outside world, for such are distractions and dangerous. The rules you knew are irrelevant. Those who enter a Ruin should do so only in the clear and certain knowledge that they may never return.'

THE SURVEYOR'S CODE.

S.

kender stood facing the blank stone wall and resisted the urge to kick it. He and Sal had tracked the Change-dead spoor of the Homunculus across several kilometres to its terminus just short of the Aad. Instead of following a straight line - as Sal explained that it had from almost as far away as the Haunted City - it wound its way around and between obstacles, sticking close to the wall of the Divide where possible. Towards the end, for no apparent reason, it had kinked to the right and headed for the cliff. There, abruptly, it ended.

*I can't see a door,' Skender said, tracing his hands over the rough sandstone. Layers of ancient sediment hung before him, preserved for eternity - or would have been but for the great rending that had separated the cliff face from its match on the far side of the Divide.

*And we can't find a hidden door by using the Change because the Homunculus has sucked it dry.' Sal paced back and forth at the edge of the wake, testing for any sign of an opening: a sliding stone, a trapdoor, anything. *But there must be one!'

Skender succ.u.mbed to frustration and kicked the stone. That gave him a sore toe to match his headache, but it seemed appropriate. Their search had come to a dead end.

He turned away from the cliff and looked around. The sun was fading into the west, casting a shadow across the floor of the Divide. Soon, that shadow would hit their location and they would lose any chance of finding an entrance.

Look on the bright side, he told himself. The tide of man'kin had finally run out. A few last stragglers had eyed the humans hatefully as he and Sal had continued on their way, careful never to leave the safety of the wake. A couple had tried to engage them in conversation, but they rarely said anything of relevance. One declared that the mysterious Angel had told it about them, but nothing else had been forthcoming. Who the Angel was, how the Angel could possibly know about Sal and Skender and why that detail was important, remained a mystery. After a while, Skender had stopped responding to calls for attention from the stony ma.s.s of man'kin.

As he stood gazing out across the Divide floor, he saw another cloud on the far side of the mighty canyon, along the eastern leg. At the rate it was moving, it would encounter the Wall protecting Laure before nightfall. Skender hoped the city's defences were ready for an onslaught.

*There has to be a way in,' he muttered, turning back to the problem at hand. *We're just not seeing it.'

*We could wait until the wake fades and try then.'

*How long would that take?'

*A few hours, perhaps.'

*The Homunculus could be anywhere by then. And if the wake has faded, how are we going to follow it?' Skender pointed at the second cloud on the far side of the Divide. *Anyway, I'm not sure I like the idea of being defenceless with so many of these things roaming around. I think we should just think harder.'

Sal sighed and sank to a crouching position with his back against the stone. *I'm very nearly all thought out, I'm afraid.'

Skender could see that his friend was exhausted. Sal had explained that few people in the wardens' search party had slept the night before; the summoning of the storm had drained him further. There were heavy bags under Sal's eyes; his attention occasionally drifted.

Skender lifted the water bottle from around his neck and offered it to Sal. The container was more than half empty, but it was the only reward they had for pressing on. No plants grew on the bottom of the Divide, so they couldn't even chew leaves or twigs for moisture.

Ignoring his own thirst, he considered what they knew. The Homunculus had an agenda of its own, one which involved the Aad. Towards the end of its journey, it had obviously made a beeline for the Ruin. The wall couldn't be the dead end it appeared to be, otherwise what was the point of coming here? The Homunculus couldn't have doubled back on itself, since it would have encountered Sal and Skender along the way. So it had come to the wall for a reason. They just had to find that reason ...

His gaze drifted upward to where the sunlight cast the top of the cliff in brilliant gold, and he wondered if he should step out of the wake and study the complex weave of air through the charm of the licence. He immediately knew he didn't need to.

He laughed, but the news wasn't all good. *I found it!' he told Sal, pointing up. *See?'

Right at the top of the cliff was a spur of rock from which projected a metal hook.

*A rope would have been tied to it.' Sal climbed to his feet and put his hands on his hips. His head tilted back to study the new development. *Or a rope ladder. Either way, the Homunculus climbed up there and reeled the ladder in behind it.'

*And here we are,' said Skender, *stuck on the ground in its wake.'

Sal nodded. He moved back several metres, trying to see what lay at the top. *There doesn't seem to be anything else up there.'

*I think that's the idea. We wouldn't have noticed anything if the Homunculus hadn't led us here. It's the perfect place for a hideout, or the entrance to one.' He looked to his left, at the pile of rubble that was the Aad's doorstep, half a kilometre away. *I can see only one way open to us at the moment, if we're going to go up there.'

Sal sighed again. *I think you're right, my friend. We can always double back when we're at the top.'

Skender put a hand on Sal's shoulder to stop him as he went to pick up the wing and head off on their new tangent. *There's something else we should think about. The ladder can't have been hanging around forever, waiting for the Homunculus to come along. The miners would have seen it. Who put it there, and why?'

Sal sighed wearily. *Yes, that did occur to me. There's no way we can know right now, unless you've had any other blinding revelations ...?'

Skender shook his head. *Alas.'

*Then we'll just have to keep our eyes peeled.' Sal handed him back the water bottle. *Let's get going before I fall asleep on my feet.'

Skender agreed wholeheartedly. They had no idea what they were heading into, but the Divide definitely wasn't safe, and he had no desire to experience it after nightfall.

The wing slotted into well-worn grooves in his fingers. He hoped Chu would appreciate the effort they were making to look after it. That hadn't been the deal at all, he thought, as they raced the encroaching shadow for the entrance to the Aad.

Sal sighed with relief as they left the Homunculus' wake. The very moment they did so, the normal background potential returned and the familiar tingling of the Change hit him. He felt in tune with the world again and revitalised for it. The wing wasn't as heavy; his feet no longer dragged. He could think again.

There was likely more to come: significant Ruins were steeped in the Change. He automatically a.s.sumed that the Ruin Skender called the Aad would be like any other. But as they reached the tumble of masonry at the base of the city, there was no surge in the Change. It was, if anything, ebbing away. He stopped to see if the Homunculus was nearby, but he couldn't see or sense it anywhere, and Skender's wind-seeing charm, which had returned upon leaving the wake, discerned no distinctive spoor of the creature. This was something else.

As they climbed the rubble towards the ruined city proper, Skender's black markings faded, and Sal's connection to the world faded with it.

*It's a Change-sink,' he said, feeling the weight of exhaustion settle over him again like a heavy blanket. *A natural blank spot.'

Skender was nodding, touching the deadened stone of a tumbled column as though it might rear up and bite him. *No wonder no one comes here. The air feels smothered.'

*Do you want to keep going?'

Skender didn't hesitate. *Of course. Don't you?'

Sal nodded, although he would have done anything rather than keep walking. Fatigue had taken root in his bones again. He had forgotten how it felt to be awake.

They climbed higher, to what might have once been street level. It was hard to tell exactly how the original city had stood because the ground had tilted under it and most of the buildings had collapsed as a result. Mounds of rubble lay between Sal and Skender and a relatively intact portion of the city. It was clear, though, that what Sal thought of as a city was really a slice chopped out of a larger metropolis. The Aad lay open to the Divide on three sides and had decayed heavily around those borders. Only the very heart of it retained any structural integrity at all.

Skender had described tunnels gaping open to the Divide near Laure. During their ascent, they had seen nothing of the sort. Sal suggested that they had been covered over by landslides and were now only accessible from within the ruins. Skender didn't have a better solution, but he did look disappointed. It would have been much easier for him, Sal supposed, if they'd found his mother on their own. They could have dispensed with tracking the Homunculus.

The Change-sink in the Aad wasn't as deep as the Homunculus's wake, but it nonetheless cut them off from everything outside the city.

*Where do you think the heart of it is?' Skender asked.

*The tower, perhaps.'

*That would make sense, I guess. It's the only recognisable landmark.'

*Does that make a difference?'

Skender shrugged. *Beats me. The study of Change-sinks is a forgotten art, even by me.'

Sal didn't ask further questions. He was more interested in whether his father had woken and given an account of his reasons for summoning the Homunculus. He almost stopped and turned back, feeling a sudden and very strong concern for Shilly.

He wanted to talk to her, to let her know he was all right.

One glance back at the Divide, which was filling with darkness as dusk's shadow swept across it, put paid to that idea. There was no going back, not through nightfall and man'kin and whatever else might be out there. He had to keep moving forward.

The last rays of sunlight rushed over the Aad, casting the tower in a blaze of golden fire. Sal stared at it, hypnotised by the strange beauty of the moment. The dead city surrounded them, its air filled with dust and decay. No animals disturbed the stillness; no plants invaded the tumbled masonry. He could have been standing at the end of history, surveying all that remained of humanity's works.

The thought was maudlin. Much of the world already looked like this. Wardens and Mages alike built homes among the ruins, constantly reminded that theirs was an echo of a bygone age, one that had been capable of works unequalled since. What had happened to those lost builders was for the most part unknown. The Cataclysm had wiped them out and left the Change in their wake. Their world was difficult to imagine.

The last light of sunset abandoned the ruins and continued its march up the side of the Divide. The city plunged into gloom.

*What do we do now?' whispered Skender. *It's going to be pitch black before long.'

*We should have brought some matches and a candle.'

*And food.'

*Let's not be greedy,' he said, refusing to regret their impulsiveness. He took in their surroundings while a dusky light lingered. *We should find somewhere to take shelter.' His body ached; the thought of rest was overpowering. *Maybe we can explore when our eyes have adjusted.'

They hurried through the ruined city. Most of the buildings had fallen in completely or were teetering on the verge of doing so. Their best hope lay south and uphill, at the furthest point from the Divide, where the ground beneath the Aad angled up to vertical. Gradually, the remaining walls became higher, their interiors less wasted. Finally, they managed to find a low building with all four walls standing and a relatively intact ceiling. There was no way of telling what it had once been, since no shapes of furniture or tools seemed evident. It had no doubt been stripped of anything useful long ago. Sal paced out the full extent of the small s.p.a.ce and declared that it would do.

*Do you want to wait here while I look around?'

The darkness was absolute. Sal could barely make out Skender's silhouette against the open doorway.

The suggestion was irresistible. *Maybe just for a little bit,' Sal said, sinking down into a corner next to where they had placed the wing. His feet and head throbbed; his throat was utterly parched. *You'll let me know if you find anything, won't you?'

*Of course. This place is far too creepy for heroics.'

Sal smiled and closed his eyes.

*Don't go anywhere until I get back.'

Skender waited for an answer, but none came. Sal's breathing became slower and more regular. He was already asleep.

*Right,' Skender said to himself. *No point in sticking around, then.'

Leaving the bottle of water by his friend's side, he steeled himself to explore the eerie and potentially Homunculus-infested Ruin. Outside, he took a moment to note every detail of the location of their hiding place; good as his memory was, he knew it would be difficult finding his way back in the dark. The cliff obscured a fair proportion of the night sky, including the moon. It was hard to see even the ground beneath his feet.

He set out slowly and cautiously, picking his way through the rubble with exaggerated care. It wouldn't do to trip and twist his ankle. He had no clear destination in mind, and gravitated to the central watchtower by default. As the largest extant structure, it was the obvious place for someone to hide, although being the obvious place rendered it the least likely to contain anything hidden. Still, Skender reasoned, he had to start somewhere. Who knew what he would stumble over along the way?

It seemed to take him forever to navigate the cramped, littered streets, even though they gradually became less buckled. The buildings around him stood taller and firmer. He tried to keep the sound of his footfalls to a minimum, but they echoed back at him with crystalline, startling clarity. He froze at the slightest noise, listening for footsteps other than his own. All he heard was the pounding of his heart and the faint whispering of wind across jagged stone.

As the tower grew taller over him, he imagined dark faces staring at him from its round windows, and the ghosts of the Haunted City came, unwelcome, to his mind. Those bodiless spirits were confined forever to their ancient towers, able to escape only with the a.s.sistance of people on the outside - people like Shilly, and Sal's mother, who invariably paid a terrible price for their effort.

He shuddered, remembering the Homunculus at its most horrific, its four arms extended to attack Marmion and its face a writhing ma.s.s of eyes, mouths and noses. The image had been easy to keep at bay during daylight hours, but the darkness encouraged it. Every time he turned, he expected to see that hideous visage about to leap on him.

A disease; bad luck; inhabited by creatures of the Divide...

Finally he stood at the base of the tower. Ten storeys high and broad enough to park several buggies, it seemed much larger than the natural cliff behind it. A single rectangular entranceway, twice his height and width, gaped open to the night air. If there had ever been doors, they were long gone. Skender tracked delicate carvings along the lintel - vines, perhaps, or snakes - but couldn't see well enough to make them out.

He still possessed a very faint sense of the Change. The heart of the sink couldn't be the tower, for otherwise no potential would remain at all. With a feeling of invading a tomb, he walked nervously into the shadow of the tower's interior and looked around.

No lights burned within, and it took his eyes a long time to adjust. There was no sign of occupation by human or animal or anything else. A rotting spiral staircase led up to the next floor and down to a bas.e.m.e.nt. Skender was unwilling to explore in either direction, for the moment. There were other places to look before he would be forced to such extremes of courage. There could be anything in the depths beneath the tower - a mausoleum, perhaps, lined with bodies he couldn't see, only touch - and the upper floors could be structurally unsound.

He ventured as far as he dared into the suffocating blackness, then hurried out into the cool night air and took several deep breaths.

From far across the black gulf of the Divide, the navigation light at the top of Observation Tower winked at him over Laure's protective Wall. The previous night, when he had soared over the city lights for the first time, seemed weeks ago. He longed to be in his bed in the hostel with the sheet over his head. His belly ached for a decent meal.

Stone clicked against stone in the darkness, away to his right. He held his breath and retreated into the doorway. It could have been perfectly innocent, but he intended to take no chances. The night was thickening around him. Anything could be stirring.

He saw nothing and the sound wasn't repeated. But his stomach rumbled again, drawing his attention to the fact that the night smelled different. The faintest hint of smoke tainted the crisp night air.

Where there was smoke, Skender told himself, there had to be something to burn. And he had seen barely a stick in his exploration of the Divide. Whatever was burning must have been brought into the Aad, and the thing that had brought it was probably nearby.

He followed his nose away from the tower. The source of the smell proved difficult to trace. Sometimes he felt he was getting closer only to lose the smell entirely down a side street. Other times, when it faded almost to vanishing and he was on the point of giving up, it came heavily on the breeze from another alley or archway.

His nose led him to the western edge of the city, on the far side from where he and Sal had arrived. The smell was definitely stronger, although its source remained hidden. It wasn't wood smoke, he thought, or tobacco; coal, perhaps, or another solid fuel. His gut tied itself in knots at a faint tang of frying that joined with the smoke in the air. Meat and toast! If the growling of his stomach didn't alert every Homunculus and man'kin for a dozen kilometres, he would be amazed.

Then, distantly, came the sound of voices. He slowed to a creeping pace as he approached the ruins of a building jutting from the base of the cliff. The door and windows were open to the night air, so he could tell that no one was inside, but his nose and ears insisted that both the fire and people lay within. Barely daring to breathe, he inched through the main door and tiptoed along the entranceway. Debris crunched under his feet, and he shushed it nervously. The voices grew louder as he explored deeper into the house where it bit into the cliff face. There, next to a room that must once have been a kitchen but was now stale and empty, he found an enormous ballroom. Or so it seemed to him, with little more than a glimmer of starlight and faint echoes to measure its extent by. Parts of the ceiling had fallen in; rubble lay everywhere. In the shadows on the far wall, he made out four wide fireplaces, each as large as his bedroom in the Keep.

Three of them had collapsed. The fourth was the source of the smoke. The fire wasn't, however, burning on the cold grate. Both the voices and the smoke were coming from above him. Skender stood in the fireplace and looked up. Far over his head, the chimney kinked suddenly to the left. Yellow light flickered.

The lyrics to a bawdy song about a tavern girl called One-Legged Meg echoed incongruously down the chimney. The singer didn't sound like the Homunculus. Faint jeers accompanied the tune. Someone barked a command and the song ceased mid-chorus.

There were people in the Aad. Skender knew he should go back to Sal, but one last thing held him back. At the top, opposite the hole through which the light issued, he made out a hook similar to the one at the top of the cliff. That explained how people came and went through the fireplace - but, once again, any attempt by him to go up there was stymied. If he and Sal could find or make a rope of some kind, he thought, they might be able to throw a loop over the hook and haul themselves up.

He turned to go, and heard a noise echo through the empty ballroom. It sounded like a footstep.

Time to get out of here, he told himself, creeping from the fireplace with steps so soft he felt he was floating on air.

*You make noise enough to shift the bones of the dead!' boomed a voice out of the darkness.

His fright was so great he actually squeaked.

The voice laughed. *That's it, my lad. Hold perfectly still. You've seen enough of the city for one night, I think.'