Carnelian retreated. In the light flickering up through the hatches he spotted a ladder going up into the ceiling. He swung onto it and began to climb. When his head butted against a trapdoor, he fumbled around until he found the catch that opened it. He clambered through it onto the tower roof.

The six ribs rose around him like the boles of trees. The air was thick with naphtha fumes. A flicker led his eyes up one of the ribs to where it held aloft a beacon. Cut black from the starry sky was a platform suspended between all six ribs. He made towards the beacon rib, cursing as he stumbled over pipes, around machinery. Bronze staples formed a ladder up the rib towards the beacon flare. He stopped dead, hearing a scratch of voices. They were coming from where the keel-beam projected out into space pointing north towards the pinhead of the next tower's beacon. A man-shape unfolded up into view. Behind, another was spread-eagled in the hoop of the dead-man's chair fixed to the keel-beam's end.

Carnelian decided to ignore the men and began climbing the staples. The rib carried him out over the leftway. He passed a board twice his height bolted to the rib that he recognized as one of the plaques that advertised the watch-tower's number to the road below.

He reached the top and found that the rib's end formed a platform. A pipe swelled open in a dragon mouth from whose jaws spluttered a smoky flame. From this eyrie, Carnelian could gaze out across the night-black land. Below, the ribbon of the leftway faded off north and south. He could see the flares of the nearest towers in both directions.

A sound made him look down. Something large and black was coming up the rib towards him. It looked up, allowing the flare light to well in the hollows of its Master's mask.

'You have come to escape the odours below, my Lord?' It was Vennel.

Carnelian backed against the flare. 'In search of solitude.'

Vennel came up to join him, unfolding to his full height. 'Prolonged proximity to the Great can be wearying. It is said, and truly, that the Chosen require the solitude of their coombs.'

Carnelian felt that the Master's bulk would push him off into space.

'Behold the brutish masses.'

Carnelian looked at the swathe of campfires twinkling at their feet. The encampment's murmur blew on the warm night wind with scents of smoke. There was also a persistent nagging like the creak of axles on the road.

Vennel coughed. This will be quite a homecoming for you, my Lord.'

Carnelian stared at him. 'What do you mean?'

Vennel turned to face him. His ivory hands began to rub each other. 'Only that my Lord must be looking with keen anticipation to returning to his coomb. That is, after being so long away.'

This was the second time that day that Vennel had tried to be pleasant. 'Yes,' said Carnelian. It was the easiest answer to give.

Vennel's hands made a dry sound as they slid round each other. Carnelian stared out into the night. His finger traced the cold curves of the flare. He noticed the creaking again. 'What makes that sound?'

'My Lord?'

The creaking.'

The creaking? Aaah, you do not know?' 'I would not ask if I did.'

'Of course, my Lord. It is made by the wheels that draw up water to irrigate the Guarded Land.'

Carnelian squinted into the darkness and thought perhaps he could just see them turning.

'Exile from Osrakum is the hardest burden to bear.'

'What exactly do these towers watch for?' Carnelian asked quickly.

'Watch…?'

'Barbarian incursions?'

Vennel opened a hand. 'Sometimes, my Lord, but mostly they are used to anticipate rebellion.' The sartlar?'

'Just so, my Lord. They are like locusts, singly innocuous, but when they swarm causing great damage. These leftways are a web spanning the land. If the local tower garrisons are unable themselves to quell a disturbance they can summon a nearby legion.'

'But there must be regions far from the roads.'

That is true, my Lord. The Guarded Land is a vast sea across which few even of the barbarians venture. Away from the roads, unseen, the cancer of rebellion can spread unchecked for months. It is only the walls of the leftways that make sure the infection is contained within a province. Once detected, huimur fire will soon destroy it.'

'It looks so peaceful.'

'Often, so does the sea.'

The roads are like causeways…' said Carnelian, thinking aloud. 'My Lord?'

Carnelian waved his hand, Nothing.

'Outside Osrakum there is only wilderness.'

Carnelian turned to Vennel, disliking the lurid reflections in his mask. 'As you said before, my Lord, I am weary. I need solitude. If you would please move aside…?'

The Master did not move. 'It is hard to imagine what reasons the Lord your father might have to stay so long out here.'

Carnelian tried to gauge whether he might manage to push past the Master.

'Of course his blood oath bound him.'

'If you know about the oath, my Lord, then you have all the reason you require. My father is an honourable man.'

'Most certainly, my Lord, most certainly, though such oaths when sworn before the Wise are enforced more by the Law than by honour. Even honour cannot explain why your father would insist on keeping an oath from which he had been released so long ago.'

‘So… so long ago?' said Carnelian. He felt as if he was trying to swallow a stone. 'How long ago?'

'Oh, many years. Oh, I see… this is news to you?'

The stone was stuck in his gullet.

Vennel grabbed him by the shoulders. 'What ails my Lord?'

Carnelian loathed the Master's touch, but the more he squirmed, the tighter Vennel held on to him. 'It is nothing. I need to sleep. Please, let me go.'

'But-'

'I bid you good night, my Lord,' Carnelian said through his teeth, jerking free, almost falling from the platform before reaching the ladder. Vennel was speaking after him but Carnelian heard nothing, saw nothing. His hands and feet moved by themselves as he descended the rib. He could still feel the Master's fingers gripping his flesh. Vennel had frightened him, but far worse was the knowledge that his father had lied to him.

PLAGUE SIGN

Carnelian woke in another ammonite cell wearing a frown and for a moment did not know where he was. There was a face in the wall. He reached up to touch its stone-smooth swelling cheek. Really, it was only a bit of a face, clipped off where one block joined another. He sat up and found there were other fragments everywhere, chipped, worn, at angles. Each leaf, eye, hand on its own block in the jigsaw of the wall.

He fell back again and stared at the snake belly of wood that crossed the ceiling. A day had passed since Vennel had told him of his father's lie. A long hard day during which they had flown along the leftway deeper into the south. He had watched his father making the changeovers with increasing stiffness until his fear for him had become a constant ache but still there was the lie; and the lie had reopened the wound of Crail's death and gushed his blood between them. Though he cursed himself for weakness, Carnelian could see no way to cross over.

The previous night, Carnelian had sent Tain to tend his father. When his brother had returned ashen-faced, Carnelian had no need to ask questions. He had turned his face to the wall and struggled for sleep.

Now he could see through a slit the sky paling blue. The air was still cool and carried the sounds of waking up from the encampment. He would soon have to confront another day.

He heard the door opening and pretended to be asleep. Through slitted eyes he watched Tain creep in and wondered where he had been. Tain looked over at him with sunken eyes then, without looking away, his foot stirred the blankets on the floor. Where had he spent the night? A picture came unbidden to his mind. Jaspar talking to Tain the day before as they were making a changeover. Carnelian had thought the slump in his brother's shoulders a result of one of the Master's threats. Cold flushed up from Carnelian's stomach. There was another explanation.