Alchymist

'It's the wrong way, said Merryl. 'Better go back.'

'I hope we can,' Tiaan muttered.

After much jerking and heaving the construct began to move backwards. They had been heading down the other tunnel for some minutes when Tiaan saw a red glow in a cross-tunnel to their left.

'We're running out of options,' said Merryl. 'Can you go faster?'

She increased speed as much as she dared, following a zigzag path away from the burning area until they hit a broad tunnel that ran straight. There were no fumes in it and they made good time. The walls and roof here were yellow sandstone, hardly tar stained at all. After ten minutes they came abruptly into blackened rock and then, where the tunnel opened out, into solid tar. The tunnel kept on.

'Is this where Gilhaelith was?' Tiaan did not like the feel of the place.

'He would have been some way ahead. We're close to the outer edge of the Great Seep – the solid edge. In a few spans it becomes soft and beyond that it's liquid tar for a league.'

'How did they tunnel it? And why?'

Merryl spoke to the huddled slaves in a language Tiaan did not know. A woman answered in the same tongue.

'They used devices powered by phynadrs,' said Merryl, 'to draw the heat out and freeze the tar hard. Why, I cannot say, only that it was mighty important to them. Matriarch Gyrull worked there every day, and a matriarch does not risk her life needlessly.'

They crept on. Objects were strewn here and there as if discarded in flight – rotting, tar-stained remnants of clothing, a small wooden chest. Further on was a distinctly human-looking body.

Tiaan caught her breath. Not Gilhaelith, surely? She drew the construct alongside, opened the hatch and looked down.

The body was small, female, and tar-impregnated. 'It has a.., withered look; Tiaan said. 'As if long dead.'

'Many people, and many animals, must have become stuck in the tar over the aeons, and been carried down into the depths. I saw a number of them over my time here, all perfectly preserved. You need shed no tear for her, Tiaan. She's been dead hundreds of years, at the very least.'

'I'll go on, just in case…' She edged the construct down the tunnel. I thought you said they tunnelled in a long way.'

About a hundred spans, I heard.'

'We're only in twenty and I can see the end,' said Tiaan.

She lifted herself up on the side, the better to see. The end of the tunnel was but spans away, a smooth, shining black bulge dotted with fragments of wood and cloth. 'It's moving!' Warm tar was creeping towards them like molasses squeezed through a hole. The tunnel had collapsed, 'If Gilhaelith was in there, he's dead.'

Five

Merryl gripped her shoulder. 'Was he special to you, Tiaan?' 'I wouldn't say that we were friends, for he had none. Gilhaelith was quite the strangest man I've ever met, and totally absorbed in himself. Yet he was good to me and I can't forget it. We'd better go, if we're to get out.'

Reversing the little construct, Tiaan turned it about and went back the way they had come. At the first intersection, Merryl said, 'Go left.'

She headed that way but was soon confronted by a baleful glow and another creeping fume.

'There's fire ahead, Tiaan. Try the other way.'

To the right they encountered a cave-in that completely blocked the tunnel. There was no hope of clearing it, for the fumes were knee high and rising. They turned back to the junction and took the middle path, their last hope.

'Fire,' Merryl said dully, after they had moved less than a hundred spans.

Tiaan kept going until it was certain there was no way past. 'What now?'

'Resign ourselves to death.'

It was hot here. Tiaan went back to the entrance to the tar tunnel. She could not resign herself to dying. Turning the construct again, she stared at the oozing face of the tar.

'Tell me about the Great Seep, Merryl.'

'It's a good league across, and hundreds of spans deep. Some say it's bottomless. Things, and creatures trapped in it, sink down and sometimes appear again, countless years later, with the wheeling of the slow currents in its depths.'

'If we remain here,' she said absently. 'We'll be dead within the hour.'

'I'd-say so.'

'How long would the air in the construct last with the hatch down, and all of us inside?'

'I don't know. Two hours? Three? Four, possibly.'

'Then let's live those extra hours. Let's risk it.' Tiaan slammed the hatch, took a deep breath and moved the construct gently forwards until it met the convex face of the tar.

Merryl's eyes met hers. Tiaan's eyes were alive for the first time since he'd met her. 'What have we got to lose?'

The construct met resistance and stalled. Tiaan moved the controls, just a tickle. The skinned tar broke and the machine surged into treacly material that smeared across the screen. Everything went black.

'Are we even moving?' whispered Tiaan. 'I can't tell.'

Merryl looked through the rear screen. 'We're going about two spans a minute. The tar's coming over the top. I can't see anything now.'

She nudged the trumpet-shaped lever. There was no sense of motion. 'It's not fast enough. It'll take an hour to get to the end and we've still got to go up to the top of the seep. How far below ground are we?'

He shrugged. 'More than a hundred spans, but less than two hundred.'

'That's another hour, probably two. Can we make it before we breathe all our air?'

'I don't know.'

'I'll have to go faster.'

'Go too fast and it may tear the construct apart.'

'Too slowly and it won't matter' she retorted.

The minutes ticked by. Occasionally they came up against an object that scraped along the skin of the construct. It was hot inside now.

'How hot is the tar in the Great Seep, Merryl?'

'I wouldn't know. It's warm on top, so it must be warmer inside.'

'Hot enough to cook us?'

'I couldn't say.'

'Do you think we're at the end of the tar tunnel yet?' Tiaan asked.

'Once the node failed, the walk of the tunnel would soon have gone liquid. We'd be in the swirl of the Great Seep right now.'

'We're too slow,' she fretted. And we're not going up. I've got to do something.'

She knew what to do but was reluctant to do it, since that would give away the secret of making thapters-constructs that could fly. But if they were going to die anyway…

'Could you have the prisoners blindfolded, please, Merry!7 And ask the slaves to turn their backs. I've got to do something to the construct and I don't want anyone to see.'

He went down. Tiaan unpacked the set of pink diamonds -powerful hedrons – and the strands of black whiskers, fifty-four of each, weighing them in her hands. So much from so little.

'It's done,' called Merryl.

She lowered herself down the ladder by her hands and Merryl caught her at the bottom. Tiaan exercised her legs at every opportunity but it was going to take weeks before she could walk properly.

Opening a hatch in the floor at the front, she identified a black box among the tangle of parts inside, and prised the lid off. Inserting the diamond hedrons into their sockets, she fed the black threads up to the back of the amplimet cavity, checking everything carefully as she worked. There would be no time to do it again.

As soon as it was done, Merryl lifted her up the ladder. How quickly she had come to rely on him. Tiaan took hold of the controls. The amplimet meshed with her snugly now, not opposing her at all. It wanted to escape as much as she did. The whine rose in pitch as she pulled up on the flight knob but nothing seemed to happen. She could not tell if they were moving upwards.

'Is it working, Merryl?'

He thought for a moment. 'You know how, when you carry a bowl of water, it moves with your motion?'

'Yes! What a clever idea.'

He found a broad metal dish among the bits and pieces in one ot the storage compartments, half filled it with water and sat it on the top of the binnacle. With a pointed instrument he scored marks around the dish, at the water level.