He bore her weight without strain and set her on her feet. Taking up the lantern, he led the way down a series of tunnel slices like thigh-high steps.

'Aren't you going to give Muss a hand?' she said in his ear.

'He can bounce down on his pointy head for all I care.'

'You don't like our prober?'

'There's something a bit off about him; Flangers said out of the corner of his mouth.

Irisis looked back but the spy was already standing at the base of the drop, as if he'd floated down. He brushed past, taking the lantern.

'He's a.strange one,' she said quietly. 'His work is always flawless, but he hasn't a friend in the world, unless you count Flydd. He eats alone, even sleeps alone, if he sleeps at all.'

'Maybe being the perfect spy is all he needs,' said Flangers. 'It's a solitary profession.'

'It's just here!' called Muss. 'Get a move on.'

They crowded into a small, circular chamber whose roof was a perfect dome of sandstone. A squat object like an inverted sombrero stood knee-high on a pedestal in the centre of the room. It had a short brown stalk on which was mounted a yellow frilled brim. It was not alive - it had been created by the lyrinx in one of their patterners.

Fyn-Mah skidded to a stop. 'Myrum, defend the entrance. Muss, check that there's no other way in. Flangers, see if you can get that.'

'There isn't any other way in,' said Muss.

'What is it?' said Flangers.

'It's called a phynadr,' said Fyn-Mah. 'The enemy make them in all shapes and sizes, to draw power from the field. We're taking it back so we can see how it works.'

'The lyrinx tried to break in for it,' said Flangers, 'so it's likely they'll be waiting when we crawl out.'

'Then it it'll be time for you to do your duty, soldier/ said the perquisitor.

Flangers took hold of the object, which slipped through his fingers. 'Can't get a grip on it,' he muttered.

Irisis touched it with her fingers. The phynadr was superficially similar to the torgnadr, or node-drainer, she'd helped Flydd to destroy, though it had been leathery. This phynadr was soft, compressing under her touch but springing back into shape when she let it go.

Flangers put his arms around it and heaved, but his arms slid off. To their right, Fyn-Mah was sketching shapes in the air. Whatever magic it was, Irisis prayed that it would work quickly. She threw a glance over her shoulder.

Flangers whipped out his sword. 'Don't damage it,' yelled Fyn-Mah.

He slid the point of his sword under the flat base of the phynadr. The edges, tinged purple, seemed to recoil from the metal, revealing a white underside. Flangers pushed the sword all the way, levered, and the phynadr popped off, emitting a musky, molasses-sweet odour.

Irisis caught it as it toppled. It was rather heavier than it looked. The phynadr bent in the middle and the base pulled itself down hard, trying to reattach to the pedestal, but Flangers kept the blade underneath. Yellow jelly oozed from beneath the cap. Fyn-Mah pushed Irisis out of the way, drew a black bag over the phynadr and swiftly tied the top. Throwing it over her shoulder, she staggered under the weight, recovered and hurried back to the collapsed section.

'I'll go first,' she said at the vertical wall.

Flangers boosted her up. 'Keep a sharp lookout.'

'Don't worry.' She crawled through. 'It's safe.'

'It would be,' said Irisis. "They want the phynadr more than us, so they'll be waiting around the corner.'

Flangers boosted Myrum, then Irisis. Muss gave Flangers a leg-up. 'Need a hand?' Flangers said.

'I'll be right; said Muss.

'Come on!' Fyn-Mah called. 'It's not far now.'

A lyrinx roared near the T-junction. Myrum shouted a battle cry and ran for it. His sword clacked against a skin plate, something whistled through the air, then he was back-pedalling, attempting to defend himself against two lyrinx at once.

He cursed, slipping to one knee. Irisis was sure he was done for, but the old soldier sprang forward, fast and low, his sword sliding neatly between the belly plates of the leading lyrinx. It sagged to the left, crashing into the other beast, and they went down in a tangle of arms and legs. The soldier dispatched the second with a sword tip to the jugular.

'We go right,' said Fyn-Mah, leading the way with the bag slung over her shoulder.

'That was a neat piece of sword work.' Irisis said to Myrum.

'Just luck,' replied Myrum. 'I was sure I was dead.'

'Dare say you will be before we get out of here.'

'Dare say we both will.'

The tunnel now headed steeply down. It was dark, but the way ahead was illuminated by a reddish glow coming from Fyn-Mah's fist. The other crystal, presumably.

It was hard work running down the steep slope. Halfway to the bottom they passed from stone into solid tar. It was so sticky underfoot that with every step they were in danger of toppling. Myrum looked exhausted, Fyn-Mah was staggering under the weight of the bag, and Flangers winced with every step. The scabbed gouges across his buttocks were bleeding. Muss had disappeared again.

'Should we wait for the prober?' asked Irisis.

'He can take care of himself,' said Fyn-Mah, moving the bag onto her other shoulder.

'Do you want me to carry that?' Irisis offered.

Fyn-Mah shook her head.

They were still heading down steeply and the air was smoky. 'How far now?' said Irisis, worrying that Flangers would break down. She felt sure Fyn-Mah would leave him behind.

Fyn-Mah did not answer, which was worrying. They swung around a corkscrewing left-hand bend together and the floor, roof and walls disappeared. Irisis threw herself to the floor on the very brink of a chasm. Flangers landed on top of her. FynMah held up her light. The details slowly emerged from featureless black.

A crevasse cut across their path. The solid tar, or rather brittle pitch as it was here, had recently been torn apart by some great force, leaving a gap of about eight spans to the other side of the tunnel. The tar wall was a sheer face of pitch, as smooth and curved as fractured glass, apart from shards that hung down, or stuck up, here and there. The bottom could not be distinguished, though it must have been a long way below them. The crevasse extended beyond sight to left and right.

The gap had been rudely bridged by an upside-down arch of pitch, a solid, smooth black curve half a span thick but no wider than Irisis's hips. Lyrinx footprints tracked across it.

'What the hell has happened here?' said Flangers, picking himself up and rubbing his backside. His fingertips came up bloody.

'The exploding node must've wrenched the ground apart,' said Fyn-Mah.

'Or the Great Seep has drawn back into the earth,' Irisis muttered, 'cracking away the solid pitch around its edges. This bridge hasn't been here long.'

'And we could run into more lyrinx at any time.' Fyn-Mah edged out onto the span, holding up her glowing crystal.

Even as she spoke, a shadow appeared from the opening on the other side. An enormous male lyrinx spread its wings and opened its bucket-sized mouth in a grin of triumph.

Behind them, Myrurn's sword scraped as he drew it from the scabbard. Irisis looked over her shoulder. A lyrinx, no, two, were coming the other way. They were trapped.

'Let me go first,' said Flangers, drawing his sword. 'That's what I'm here for.'

'Stay back!' Fyn-Mah had one hand in her pocket. She gave Irisis a sideways glance, as if to say, Do you now question my judgment? 'When I give the word, cover your eyes.' She crept a little further along the bridge, which curved down then up, like a suspended rope.

The lyrinx stood at the other end, its eyes glittering in the light from the perquisitor's crystal. It had something in its left hand. Irisis could not see what, but her heart began to thump. This was no ordinary lyrinx. She could sense the power; the intensity. Many lyrinx had a talent for the Secret Art, though few used it for anything but flying. This creature was different. She sensed that it was a mancer every bit as powerful as the great human or Aachim mages, and the device in its hand felt potent.

Myrum sang out, 'Might need a bit of help, Crafter.'

She whirled. A pair of lyrinx were advancing from the tunnel, side by side. Drawing her sword, she stood shoulder to shoulder with Myrum. From the corner of her eye she could see Fyn-Mah on the bridge, only waist high to the mancer-lyrinx.

It let out a deep, roaring bellow that echoed strangely off the hard walls. The left hand slid out, palm upwards. Irisis felt a hot glow on her cheek, had the sense of an invisible cloud roiling outwards, and the floor softened under her. She instinctively lifted one foot, but when she put it down again, the surface had already hardened. The other foot did not move. She was stuck, like a fly to tar paper.

She jerked as hard as she could. It jarred the muscles of her leg but her boot remained firmly embedded in pitch. The two lyrinx were also stuck, though they probably had the strength to pull free.

Myrum cursed and began to hack at the pitch with his sword. She did the same, trying to watch the bridge and the enemy at the same time. Flangers, being closer to the source, was more deeply embedded, while Fyn-Mah was buried to the ankles. Lacking a sword, she had no way of freeing herself.

Flangers hacked the laces off his boots and pulled his feet out. Tearing off his socks, he ran out onto the bridge.

'Go back,' cried Fyn-Mah. 'You can't save me.'

'Then I'll die trying.' He hammered the brittle pitch around her boots with the point of his sword, sending chips flying everywhere.

'Take this and go! It's more important than I am.' She heaved the heavy bag to him.

He lashed it to his belt but kept hacking, the bag banging against his calves as he worked. There's nowhere to go, Perquisitor.'

'Take it!' she roared. 'It's an order, soldier.'

It was too late. The mancer-lyrinx was edging towards them, moving tentatively as if unsure whether the bridge would hold its weight. This small chasm was a dangerous place in which to fly, if it had to.

'Now would be a really good time to use whatever you were keeping for an emergency,' yelled Irisis, still prising at the pitch that held her boot fast.

Fyn-Mah just stood there, one hand holding up the glowing crystal.

Why didn't the mancer-lyrinx blast them? Irisis prised away. Her boot came free, along with a lump of pitch resembling a club foot. She smashed it off. Did the creature want to take them alive? That didn't make sense, since the other lyrinx had tried so hard to kill them. It had to be the phynadr.

The lyrinx edged closer, the bridge shivering under its weight. The beast gestured towards the bag. Irisis could see the knots in Fyn-Mah's jawline. She was terrified but defiant, and Irisis could not but admire her for it.

Behind Irisis there came a roar as one of the lyrinx freed itself and leapt, its foot trailing blood. Myrum, who was still stuck, slashed wildly at it. The lyrinx landed hard on the torn foot, lurched sideways but recovered to beat through Myrum's defences. Throwing its arms around him, it squeezed him against its chest plates. Ribs cracked as Myrum fell backwards, carrying it with him. The great mouth darted at the soldier's head. It reminded Irisis of the time she had been held beneath one of the lyrinx, and only Flydd's heroism had saved her.

She swung her sword against the back of the creature's armoured skull with every ounce of her strength. The armour cracked and the lyrinx's head was driven into the floor. It did not move, though the blow could only have stunned it.

Finding a gap between the skin plates of its side, she drove her sword through the ribs.

It took all her strength, and all of Myrum's, to get him out from under the fallen creature. He was so battered and bruised he could not stand up. The second lyrinx was still nving to free its feet from the pitch. She hacked Myrum's boots out.

On the bridge, the mancer-lyrinx was almost within reach of Fyn-Mah. The bridge shuddered. The creature reached out for her. Her eyes fixed on it. Fyn-Mah tossed the crystal towards the roof of the chasm and yelled, 'Cover your eyes!'

Irisis, watching the crystal arc up into the darkness, screwed her eyes shut. The explosion of light burned her eyelids and sent blood-red pulses through her brain. She opened her eyes, dazed and dazzled, to see the mancer-lyrinx topple head-first off the bridge. Its wings spread as it hurtled downwards, but they were insufficient to support it without the aid of the Art, and the exploding crystal had filled the ethyr with echoes, preventing it from drawing on a distant field. Only devices that stored power, like Fyn-Mah's crystals, could work here, and once that power had been used they were useless.

The bridge softened and began to droop beneath Fyn-Mah's feet. She pulled one foot from its boot and heaved at the other. Flangers scrambled down the curve to her.

'Go back,' she screamed. 'Save the phynadr.'

Fyn-Mah was going to do her duty to the bitter end. You're a better woman than I'll ever be, Irisis thought.

The curve of the bridge steepened and thinned like molasses sagging between two spoons. Soon it must break, plunging Fyn-Mah into the abyss. Flangers kept moving towards her as the stretching strand of pitch pulled her away but, as he grasped her outstretched hand, the bridge snapped. Fyn-Mah fell, pulling Flangers with her. He threw his other arm around the pitch. They swung on the end of the still lengthening ribbon, then disappeared into the darkness. Irisis heard a thud as they struck the side of the chasm, a muffled cry, then nothing. Darkness, utter and complete, swallowed the world.

'Don't suppose you've got a flint striker in your pocket.' Myrum's voice came from not far away.

She felt it out and snapped it a couple of times so he could see the sparks. 'Here. What's happened to the other lyrinx.'

'Was still stuck, last I saw.' He in a lantern. The creature lay on the floor, one foot at a strange angle as if it had broken its ankle. Its hands were pressed against its eye-sockets, its face covered in red-stained tears. 'Burned its eyes, I'd reckon. They don't like bright light.' He put his sword to the defenceless creature's throat.

Irisis turned away. It had to be done but she did not have to see it. 'Bring the lantern when you're finished. We'll have to recover the phynadr, and the little beast if we can, though I don't see how we're going to get out again.'

'I can smell fresh air,' said Myrum shortly. 'It must be coming from the other side.'

'No use if we can't get to it. Got any rope in that pack of yours?'

'As it happens, I have.' He produced a hank of thick cord, knotted one end around his burly torso, and the other around hers. 'Nice chest you've got here, Irisis.'

'This is as close as you 're ever getting to it,' she said with a cheerful grin.

He was philosophical. 'Ah well. I still have my dreams.'

'I hope you live to have many more.'

'What if you go down on the rope, and I hold you?'

'I'm heavier than I look.'

He eyed her up and down. 'Even so.'

All right, but keep your thoughts on the rope.'

His gummy smile widened. 'Don't know as how you can dictate terms when I'm holding you up.'

Myrum lowered her over the edge, which turned out to be an overhang. Irisis held the lantern out in her right hand, though its smoky yellow glow barely penetrated the blackness. Heat wafted up past her and, as she swung back and forth, she caught a glimpse of something glowing in a crack, a long way down. It looked like lava, but wasn't. The tar was on fire and it would burn wickedly if she ended up anywhere near it.

Recalling that thud, she directed the lantern light along the nearer side of the crevasse. Here the wall consisted of a series of sheer miniature cliffs, broken by narrow platforms topped with jagged spires of pitch, some as sharp as broken glass. Irisis cringed at the thought of crashing into them.

It was hard to see, for the black surfaces reflected only an occasional glitter. Unable to get close enough to the wall because of the overhang, she began to swing back and forth on the rope.

'You all right?' called Myrum.