'If we raise them they might knock us off the Ladder,' Osidian hissed in his ear.

'What…?'

'A sky-saurian roost.'

Carnelian scrunched up his nose. 'It stinks of fish.'

'Just be glad there are no saurians nesting in here,' snapped Osidian.

'Ugh!' grimaced Carnelian. The floor was oozing, sticky.

Osidian's hand grabbed his arm and dragged Carnelian after him, deeper into the cave.

'Do you have a light?' asked Carnelian, wincing at each moist footfall. There was no answer. 'I said, do you-'

'I have not grown suddenly deaf. The answer is no.'

'But-'

'I did not think we would need it. We could have brought a bed as well, if I had thought of it, but perhaps my Lord might have also complained at having to carry that down the Ladder.'

Carnelian decided it might be better to say nothing more.

The noisome walk ended at something like a low smooth wall.

'Jump up,' said Osidian.

Carnelian felt him lurch past. He slid his hands up the wall, over the edge. The ledge above it was damp. He brought his fingers near his nose. They smelled of nothing worse than must. He pulled himself up and found that he was sitting on a narrow flat space. He could feel a column backing it, an ankle of stone, with another beside it. He slid his hand up to the knees.

'Will you stop fidgeting around! Lie down and sleep,' said Osidian.

Carnelian lay down. His tunic and trousers clung to him. The air around him was as moist as breath. 'What is this place?'

There was no answer, just the sound of Osidian breathing. He supposed there was no point in telling him that, fishy stench or no fishy stench, he was hungry. Carnelian waited until he could hear Osidian's breathing slow and then he shifted closer to him, buried his nose in the sweaty-smelling cloth of his back and quickly fell asleep.

The raven hopped into the air, flicking open its fan-feather wings. Carnelian tried to catch it, his fingers shredding the air like its black pinions. The other distinct half of him was there without a face, touching the whole surface of his skin. He clenched the anchor grip of their hands but its fingers were squeezing to blood. The raven's eye stared white as an egg. A red tear leaked from the corner with each blink.

'Flee with me away from here,' the raven screeched. Its beak was the pin holding everything together.

But Carnelian would not abandon the faceless half of him. Looking round, he tumbled falling. The red earth caught him. Grit in his eye. Sinking. He struggled to stay perfectly still. Every movement trembled pebbles and scratched his skin deeper in.

'Away from Her.'

The earth brimmed over him like honey round a stone.

Warm pulsing red darkness beating him like a heart. Buried alive. Opening his mouth to scream let dust pour into his stomach, into his lungs. Drop by drop, moisture sucked out of his husk till his organs rattled inside him like seeds.

Carnelian jerked awake to see a creature hovering over him, its wings splayed like hands to grab him.

'What is wrong?' said the creature. Carnelian recognized Osidian. As his friend crouched, Carnelian saw the idol of stone behind him, a winged man, looking as if he had only at that very moment descended from the heavens.

The Black God,' he breathed.

As Osidian looked up, his shoulders relaxed. The Wind Lord.'

Carnelian could not stop staring. The idol's empty eye sockets were terrible. From the left eye, tears dribbled down the stony cheek. 'An avatar of the Black God.'

Osidian shook his head. 'A false Quyan deity. The only true gods are the Twins.' He smiled. 'Besides, our friend here poses no threat. Has he not given us the comfort of his hospitality?'

The comfort…?' Carnelian said, stretching the stiffness from his arms, arching his back. Osidian was gazing towards the light. The narrow shrine with its corbelled vault ended in a triangle of morning so bright it hurt his eyes. Its sloping walls were stiff with the carved wings of wind creatures. Rubbish clotted the floor. 'Do we have to wade back through that?'

'Unless, in the night, my Lord has been gifted with a sprouting of wings,' said Osidian. He made a pantomime of looking for them.

Carnelian slapped the hands away from his shoulders.

Osidian grinned. Carnelian was embarrassed by the look in his eyes.

As they slid down to the floor, the filth oozed up between their toes till it seemed they stood on the stumps of their legs. They exchanged looks of disgust and began to squelch off to the entrance.

When they reached it Carnelian glanced back. The winged god looked like a great raven. He realized something. 'His altar was our bed.'

'You would agree that it was better than the floor,' said Osidian. 'Do you think he begrudged us it?' He did not wait for an answer but walked out into the morning.

Remembering his nightmare, Carnelian looked back into the shrine uneasily, then followed him.

He stopped. At their feet was a tangling, as if a net had been cast over a skyful of birds leaving only their bones and tattered green feathers. Thorn trees,' he said, his voice loud with disappointment. He had expected the Yden to be more lush.

The air tore with screams and something like a shaking of many blankets as the cliff of the Pillar came to pieces round them. He ducked with Osidian as a vast shape wafted over them. He glanced up to see the air screeching with leather kites.

'It seems you have woken our fishy friends,' cried Osidian. 'Come on.'

Half crouching they fled, laughing, down the wide steps crusted white, through a shimmering stink of ammonia and rotted fish. Above them, the creatures circled on fingered wings, slicing the air with their pickaxe heads. Soon the white on the steps was only a splatter, the air cleared, cracks became jagged with weeds.

The trees formed a wall of thorns. Through their knotting branches, the sky was a mosaic of blues. Looking back, Carnelian could see nothing of the steps. Up the cliffs he found the nodules of the sky-saurian nests and perhaps, though he could not really be sure, the Ladder's zigzag. The Pillar soared up to fill the sky. Somewhere up there were the Halls of Thunder.

Carnelian's gaze came back down to earth. Osidian was walking off clothed to the waist in dust clouds. Carnelian followed him, frowning. Here and there an angled paving stone showed where a road lay under the dark earth. Peering into the thorns he saw the cracked carvings running along its edge. The road curved off to the north but Osidian turned off it and ducked into the thicket.

'Hold on,' Carnelian shouted after him.

Osidian's head poked out from the thicket as if from a hut.

Carnelian pointed. The road goes this way.'

Osidian smiled. 'So it does, into the Labyrinth. We, however, go this way.' He pointed into the thicket. 'Be careful of the thorns,' he said with a grin and disappeared again.

Carnelian frowned when he reached the place where he judged Osidian had gone into the thicket. After much squinting, he managed to see him there, moving away through the tangle along something like a tunnel. Carnelian gave the road one last envious glance before ducking in among the thorns.

The tunnel forced Carnelian to bend his back. Thorns snagged his clothes so that he often had to stop to unhitch the cloth. Several times, mockingly, he muttered, 'Be careful of the thorns,' and then growled.

He struggled to catch up with Osidian, wanting to berate him, but when he began Osidian turned and lifted up his hands to show his own red scratches and Carnelian had to give him a grudging smile and close his mouth.