'We shall not enter her crater today,' said Aurum.

Carnelian swung round. 'In the thousand names of the Twins why not, my Lord?'

'Because it is too far.'

'What is that there?' Carnelian pointed a stiff finger down the road at the umber burnt into the edge of the opalescent sky.

'Can you not see how low is the sun, my Lord? There is still a long ride to the City at the Gates.'

'But my father-'

'We would not reach the gates themselves before nightfall. We would be forced to lodge in the city. It would do the Lord Suth little good to spend a night breathing the vapours of the Gatemarsh. In the morning, we can finish the journey refreshed.'

'We must think of the Lord Suth,' said Vennel. He waved a hand. The vapours…'

'It is hard to see, my Lord Aurum,' said Jaspar, 'how one could find spending a night in another stinking shed at all refreshing. But, no doubt, anticipation will make the reaching of one's coomb all the more delightful.' He turned to Carnelian. 'One finds that pleasure is so often enhanced by the delay in its consummation, neh?'

It was all Carnelian could do to stop himself ripping away the Master's mask to punch the dirty smirk off his face.

Watch-tower sea three rose near the edge of the Gatemarsh: a vast mirror scribbled over with mud calligraphy. The City at the Gates was like a half-rotted golden starfish. Causeway threads pulling out through the marsh formed its arms. A gilded mould grew in the angles. Behind lifted the Sacred Wall of Osrakum, as if the sun had been hammered flat to make a frieze for the darkening sky.

Carnelian stood stirred by fear and hope for his father, for his brother, but also he felt a yearning that had the taste of the silver box. The starfish's head seemed to have cracked a fissure in the golden frieze. His heart was like a bird trapped in his ribcage. That fissure could be nothing other than the beginning of the canyon that led up into Osrakum. He would walk in her crater before the next setting of the sun. It was easier to imagine entering the Underworld.

Carnelian struggled under his father's weight to the watch-tower door. While he was getting his breath back, his eyes were drawn back to Osrakum. Aurum was a black spindle around which the Sacred Wall vibrated its gold. He was talking to a Maruli from whom he kept his distance. He threw something that landed on the ground between them. The man bent down, grimacing from the pain, hesitated a bow, crawled into a saddle-chair and sped off. Carnelian watched him shimmer away to nothing against the gold, then heaved his father into the watch-tower.

The Masters had locked themselves away and so Jaspar was out of reach. Carnelian knuckled patterns of light into his eyelids. Beside him, his father was restless, hot, stuttering half-words, sighing. He was the voice of Carnelian's despair.

The babble stopped. Carnelian came awake. He stood up and saw the moonlight catching his father's open eyes. His lips moved. 'Forgive me.'

Carnelian took his hand. It was cold and heavy. He laid his lips against his father's brow and felt that he was kissing underwater stone. He prayed to the Twins, Their avatars, the Two Essences, but all were deaf. He kneaded the Little Mother in his hand and promised her anything if she would save his father. He found the bundle with his clothes and rummaging in it felt the roughness of Ebeny's blanket. He tugged it out and burrowed his face into it. For a moment he could believe that she was there with them. He pressed it harder to muffle his sobs. When he had done, he stood up and spread it over his father, pulling its edge up so that his father could smell her too.

'Sleep now,' he whispered and his father obeyed him. Carnelian felt for his hand through the blanket and squeezed it and then lay down.

He jerked awake breathing hard. His blanket was soaked with sweat. Above him, his father was muttering some fevered incantation. A scent of horror smoked around the edges of the cell. He was reluctant to return to the red face smiling in his dreams. Standing, he swayed a little and stared at the thing muttering on the bed. He did not recognize it. It was something malevolent he had to escape.

Robe. Mask. Cold stone under his foot. He went out into the silent hall. All the other doors were closed. Moonlight fell in columns round him. He climbed the ladder to the roof.

Through the copse of the ribs he glimpsed a wonder of stars. He edged across to the inverted arch between the northernmost ribs. The keel-beam ran out from the edge of the roof to the lookout in his deadman's chair. He walked out towards him. The man turned. Imagining his stare, Carnelian wobbled. He walked further out. Below, the leftway ran its dim canal.

'Master?' said a fearful voice ahead.

'I will take your watch for a while,' Carnelian said.

The man hesitated, then swung himself up onto the beam into a crouch.

'Wait on the roof.'

The man ducked past with a waft of stale sweat.

Carnelian took a few more steps forward. A cylinder pushed out from the end of the beam. The hoop formed a halo around this. He reached out, grasped the hoop then swung down onto the cylinder. It rotated, almost throwing him out into space. Trembling, he used the hoop to pull himself back into balance. He was panting hard. Now he understood why it was called a deadman's chair. At least the fright had brought him some relief from the foreboding. He looked out.

Down on the road the Marula's fire had gone out. The land spread away textured with shadow lumps. The snuffling of animals and some voices seemed eerily close. In the direction of Osrakum, the starry sky fell into a gulf of darkness. The heart of the city glowed dimly beneath it. Faint traceries showed the causeways. The land between seemed to be adjusting. He strained to hear something, some human sound that might come to him from the metropolis. There was only the rasp of frogs and, intermittent; y, the cries of creatures stalking the marshes. He closed his eyes. Breathed deep the sweet air.

He heard a cry, nearby, muffled. He craned round and saw yellow light in one of the tower's top-storey windows flicker then go out. His father. He scrambled back onto the beam and sprinted along it to the roof. The hatch formed a glowing rectangle. He found the rungs of the ladder and began descending.

'It wields a dagger.' A woman, voice raised in anger. No, it was Vennel.

Carnelian looked through the rungs down into the hall. Vennel loomed with Aurum coming up holding a lantern. Behind them both stood Jaspar. The three formed a frozen tableau of immense black figures, their gold faces smouldering against the deathly white stripe of their throats. All the masks were half turned away, peering off into a dark corner. Aurum lifted the lantern high, so that its edge of light pulled up the further wall. On the floor was the tight hooked figure of a man. A black man. A Maruli, shaking, with sliding slitted eyes and a blade hanging down from his fist.

As Carnelian slipped down into the room, the Maruli turned, sensing him. Carnelian knew the man's face. He saw it twisting, the lips drawing back from feral teeth, hissing.

Aurum took a step forward. 'Abase yourself before your Masters, slave.' His voice filled the hall.

The black man flinched but his face remained hard with defiance.

Aurum unmasked to reveal his cold white anger.

The black man cowered away, almost closing his eyes. The blade trembled in his grip.

'Kneel!' boomed Aurum.

The black man closed like a mussel.

'Hold these,' Aurum said quiedy, thrusting the lantern and mask into Vermel's hands. Shadows slid this way and that as Vennel fumbled, then they steadied.

'Come, kneel, it'll be better that way. It'll be better,' coaxed Aurum.

The black man's knees cracked against the floor. He bowed his head, his arm still out to one side, stiff clutching the knife.