They both turned, hurrying their pace as they made their way back the way they'd already come, passing the junction from which they'd emerged.

It was from that tunnel that another sound issued.

A loud, wet noise that Mason thought sounded like soggy bellows being rhythmically pumped. Along with the sound came a blast of noxious air, so vile and powerful that it made both men recoil.

*Keep moving,' Mason coughed, pushing Coulson before him.

They moved as quickly as they could, almost managing to jog down the tunnel now, desperate to be as far from the sound and the vile smell as possible.

They splashed through freezing water, Coulson almost stumbling. He shot out a hand to steady himself and hurried on, keeping pace with Mason, almost colliding with him. The shotgun scraped against the stonework and Coulson gripped it tightly to stop himself from dropping it.

*The tunnel's sloping downwards,' Mason exclaimed, almost slipping over on the wet floor.

Coulson seemed less interested in the contours of their underground domain than he was in the increasingly loud noise that was filling the tunnel behind them. He turned and waved his torch behind him but could see nothing.When he looked back in Mason's direction once more he could see that the teacher was squatting down, examining something on the tunnel floor in front of him.

Coulson joined him and Mason pointed at the object before them.

It was a man's shoe. There was fresh mud on it.

*First the silk, now this,' Mason echoed. *Looks like we're going in the right direction.'

As they walked on they were both aware of the heavy silence that had settled in the tunnel. Only the sounds of their own laboured breathing filled the stone shafts now. The unidentifiable rasping that they had heard all too many times was now absent.

Mason raised a hand to halt his companion.

The tunnel was silent again.

Coulson merely nodded slightly, urging Mason forward with a gentle shove in the back.

*Let's keep moving,' he insisted.

Mason nodded and did as his companion advised.

He recoiled slightly as a large cobweb brushed against his face and he pulled the thick strands from his hair as he walked on, noticing something about twenty yards ahead of them. He held a hand out to halt Coulson, raising his finger to his lips when he noticed that the other man was about to speak.

Mason switched off his torch and pointed towards what he'd seen.

There were two lights flickering in the darkness ahead of them. Both men advanced towards the pinpricks of luminescence and saw them grow slowly from small points into fuller flares.

On either side of the tunnel, placed carefully on fallen brickwork to keep them out of the water on the muddy floor, were lamps. The sickly yellow glow they gave off reminded Mason of dying candles and he moved closer to inspect the sources of light.

Both the lamps were plastic. Very similar to the kind of battery-powered lights used for camping purposes. Mason wondered how long ago they'd been placed there.

He was still wondering when Coulson walked a couple of steps ahead of him, indicating more of the dull points of light.

There were more lamps set up along the rest of the tunnel. Mason counted at least twelve of them.

Coulson switched off his torch and jammed it into his belt, gripping the shotgun with both hands now as he walked forwards. The lamps gave off enough light for both men to move with reasonable sure-footedness.

*Who put these here?' Coulson murmured but Mason could only shake his head. He was more concerned with what the lamplight had uncovered.

Propped against the tunnel wall less than ten yards ahead of them was the body of Andrew Latham.

78.

Mason advanced slowly towards the corpse, followed now by Coulson.

For a second, Mason wondered if the boy might still be alive but, as he leaned over the figure he knew that was impossible.

Even in the dull light of the lamps, Mason could see that the boy's flesh was pale, almost white but it was puckered around not just the mouth, eyes and nose but everywhere. Latham's body looked as if it had been left in warm water for a very long time, the flesh pruned and crinkled. Mason reached out one tentative finger and touched the dead boy's cheek.

It was as dry as a bone. The corpse looked mummified. Shrunken, as if all the internal organs had been sucked out and discarded but Mason could see no wounds on the corpse. Apart from its dried and shrivelled state it was untouched. There were no cuts, bruises or abrasions anywhere to be seen on it.

*He looks like he's been down here for years,' Coulson murmured, transfixed by the sight of the body.

Mason exhaled and nodded almost imperceptibly.

*Who could have done that to him?' Coulson continued.

*I don't know,' Mason breathed, stepping away from the body. *Come on, we've got to move on. We've got to find Kate.'

Coulson shook his head.

*Whatever killed him is down here with us,' he snapped. *And I don't want to end up like him.You want to find the girl, you go on.'

*And what are you going to do?' Mason rasped, gripping the other man's arm. *Find your way back through these tunnels? Make your way out and go and fetch the police?' He glared into Coulson's eyes.*If we stay together we've got a chance. If we separate we might not get out of here alive.'

Coulson met his gaze and held it.

*What are you going to do?' Mason went on, his voice now little more than a whisper.

Coulson shook loose of the teacher's grip and nodded. *We go on then,' he grunted. *But if I see a way out of here I'm taking it. You want to stay down here and find your fucking girlfriend that's your business. I'm getting out as soon as I can.'

*Understood,' Mason intoned then pointed in the direction he felt they should go.

There was a large hole in the right-hand wall of the tunnel.The brickwork looked as if it had, over the course of many years, simply disintegrated. There were several large cracks in the ceiling too, some of them leaking mud like blood seeping through tears in overstretched skin. Large lumps of stone were scattered across the tunnel floor and Mason looked warily at the ceiling, shining his torch nervously over the rents.

Mason ran his hand over the wall and another piece of stonework simply fell to the ground.

There was a loud groaning sound and both men froze. Moments later there was a rumble and they both felt the ground shudder slightly beneath their feet.

Coulson steadied himself against the nearest wall and felt vibrations coming through the stonework as if someone on the other side were hammering it.

A lump of stone the size of a fist fell from the tunnel roof, missing Mason by inches.

*Jesus Christ,' Coulson gasped. *The roof's falling in.'

They ran as fast as they could, happy to be swallowed by the gloom, wanting only to be away from the lumps of rock and stone that were starting to fall all too numerously. Mason shot a terrified glance behind him and one horrific thought filled his mind and would not budge.

We're going to be buried alive.

He ran, no longer caring whether or not Coulson was with him. He was unconcerned by the darkness and the stench and the mud that gripped his feet and slowed his pace. He wanted only to be out of this vile subterranean labyrinth. He wanted only to see daylight and to smell fresh air again and not inhale this fetid stink of corruption and decay.

Coulson slipped, fell and dropped the shotgun as another large chunk of the ceiling slammed down, accompanied by some thick clods of mud. He scrambled to his feet, paused a second and almost bent to pick up the weapon but his fear overcame all other instincts and, instead, he hurled himself forwards towards a curve in the tunnel. As he hit the wall his torch went out.

Mason shot his own torch beam behind him, trying to see the extent of the collapse but, as Coulson dived forward he slammed into him, almost knocking him flat and dashing the torch from his grasp.

Blackness enveloped the two men totally.

Mason dropped to his knees, desperate to find the torch again.

The tunnel collapse he had feared had not happened and for that he was grateful but the loss of the light, however meagre, was almost as intolerable. He felt his hands slide through freezing mud that grasped as high as his forearms and he crawled like a blind man, searching for the torch.

Coulson flicked on his own torch again and the beam illuminated Mason's terrified, mud-spattered face.

The teacher looked up briefly at his companion then felt something familiar beneath his probing fingers and he tugged the torch from the glutinous ooze beneath him, pressing frantically at the on/off switch.

The light came on but it was only through a thick film of slime. Mason wiped as much as he could from the plastic, relieved that the beam of light once again cut through the darkness. He stood up, his heart hammering madly against his ribs.

Coulson put a comforting hand on his shoulder and Mason nodded as if to signal that he was regaining control.

*Come on,' Coulson said, stepping away from the fallen debris.

Mason followed him, aware that the ground beneath their feet was now more solid.

He shone his torch down and saw why.

Both of them were standing on damp wood.

That realisation was eclipsed a second later as the wood splintered beneath their weight.

They both fell.

79.

Mason slammed into the rock with an impact that tore the breath from him.

He rolled over clutching his right side, convinced that he'd shattered at least one rib.When he breathed, a sharp pain bit into his side and chest and he groaned as he rolled over. He couldn't see a hand in front of him in the gloom but he realised that he and Coulson had fallen no more than ten or fifteen feet through the floor of the tunnel above.

Coulson.

Where was his companion, he wondered? He'd fallen at the same time and Mason had heard his scream of shock and terror as the tunnel floor had swallowed them. Where he was now, however, Mason had no idea.

*Coulson,' he whispered into the darkness.

No reply.

Mason crawled a couple of feet in the darkness and called the man's name again.

This time it was met by a low groan.

*Here,' Coulson breathed.

Mason scrambled in the direction of the voice, dragging himself through the freezing wet mud.

Coulson was propped up against a rock, one hand pressed to his head, his body shivering.

*Are you all right?' Mason grunted.

*I think I've broken my ankle,' Coulson slurred. *I can't move it.' He sounded like a drunk.

*You're going to have to,' Mason sighed.*I'm not leaving you here.'

*Just get out, leave me here. Send help when you get out.'

*It might not be broken,' Mason insisted, digging into his pocket and pulling out his lighter. He flicked it on, holding the flame up to illuminate his companion.

Coulson's left leg was extended before him and Mason could see that his foot was twisted at an impossible angle but it wasn't the broken ankle that was concerning him. It was the damage to Coulson's skull.

Mason held the lighter higher, the sickly yellow light illuminating the full extent of the damage.

*What are you looking at?' Coulson slurred and, at last, Mason realised why his speech was so distorted.

There was a hole in the back of Coulson's skull the size of a tennis ball and through it, Mason could see a greyish-red matter bulging from the hole in the other man's skull. He realised with revulsion that it was brain. Coulson's eyes rolled briefly upwards in the sockets and he tried to speak once more but, this time, no words, just a stream of blood poured from his mouth. Rivulets of the dark fluid were oozing from his nose too.

*Oh Christ,' Mason murmured, unable to keep his reaction in check.

Coulson's head flopped backwards, his tongue lolling from his mouth.

*Coulson,' Mason hissed. *Stay awake. I'll get out. I'll get help.'

It was already too late.

*Come on,' Mason said through gritted teeth. He held up his lighter once again in an attempt to see where they were. It looked as if they'd fallen into a culvert of some kind, two of the sides were smooth, the other two were bare rock. Mason glanced upwards to the wooden slats they'd crashed through then held the lighter away from him once more.

The flame was flickering, blown by a strong breeze. Buffeted so much he feared it might go out.