For the first ten feet or so, the walls were whitewashed particle board; beyond that, the tiles of the original tunnel appeared. At the point where they joined, I found the switch at ground level and threw it. For a long moment, nothing happened. Then the lights woke slowly, dithering in spastic strobe before finally settling for on.
The tunnel gaped open in front of us like the gullet of Leviathan. It was unnerving, a trompe l’oeil in reverse, opening up a third dimension where the wall of darkness had seemed flat and solid and close to. Half a mile or more to the river, and the underpass went all the way there. This would be a bad place to get caught with the demon between us and the outside world.
I turned to Trudie. ‘Stay here,’ I told her. ‘Keep lookout for me.’
She met my gaze squarely.
‘No,’ she said.
‘This is a dead end.’
‘I don’t care, Castor. If he comes back, the two of us together have got a better chance of staying alive.’
I was going to argue the toss because she was flat-out wrong on that one, but she forestalled me by walking ahead into the tunnel. I had no choice but to follow.
Without discussion, Trudie took one side of the tunnel and I took the other. We moved fast, scanning walls and floor for any obvious breaks, openings or trapdoors. The dust underfoot deadened the echoes of our footfalls, but the sound of our breathing came back to us, amplified and distorted, from the tunnel’s further end, adding to the illusion that we were being swallowed alive.
We kept moving, roughly in sync. I was setting a good pace, but Trudie’s long stride easily matched mine. There was no sign of any opening off the tunnel ahead of us; it seemed to extend into unfathomable distance.
Then I spotted the mouth of a cross-way. It was invisible from a distance because the white-tiled tunnel wall stood proud at that point, concealing the actual opening until we were very close to it.
We quickened our pace until we reached the intersection. The right-hand tunnel was blocked after about ten feet by a concrete wall that looked fairly new. Road signs and traffic cones were stacked in this shallow space in great profusion. On our left the side tunnel went on for about twenty feet and then angled sharply, again to the left.
It made sense to cover this side branch first, rather than leave it to be explored on on the return leg. We walked quickly to the corner, skirting it widely to avoid being surprised.
Ahead of us there were only a further ten feet of corridor, ending in another wall of grey concrete. Set into it was a door, over which a sign - hanging slightly askew - read THAMES FLOOD CONTROL CENTRE.
‘That’s just surreal,’ I muttered.
‘It’s obsolete,’ Trudie answered, her voice pitched as low as mine. ‘Before they built the Thames Barrier, every borough had its own flood warning centre. This must have been where Camden’s was based.’
We tried the door, found it locked, and went back to the main corridor. As we advanced now, I became aware that there was something wrong with the endless perspective of the tunnel ahead of us. The proportions were subtly - and then not so subtly - off true. A few moments later, Trudie muttered a profanity.
‘The ceiling is closing in on us,’ she said.
She was right. It had been high above our heads when we started, but now it was almost close enough to touch. As I stared up at it, I heard a distant basso rumble.
‘The road tunnel,’ I said. ‘They built it inside the shell of the underpass. The road is right over our heads here.’
This stretch of the tunnel was more untidy, with piles of bricks, steel buckets and even the occasional hammer or trowel stacked against the wall or casually dropped on the floor. Dead leaves had drifted in ragged heaps against all of these objects, giving each of them its own dull brown comet tail.
We kept on moving, and the distance between floor and ceiling kept on narrowing, so that after another couple of minutes we were having to stoop. It was hard to fight off a feeling of claustrophobia. Trudie reached up and touched the underside of a manhole cover, gave it a tentative push, but it was rusted into place. It was obvious it hadn’t been opened in decades.
Up to now the air had smelled only of dust and damp stonework, but in this stretch of the tunnel it had curdled into something much more unpleasant: a sweet-sour tang like rotting vegetables, overlaid with something hard-edged and chemical. It was subtle at first, but it intensified as we went forward.
Up ahead it now looked as though the converging perspective lines met within a few hundred yards, rather than at some distant horizon. I was about to make some remark about running out of road and suggest we turn back, when I realised that I’d been tricked again by the flat light and the ubiquitous white tiles.
The floor and the ceiling didn’t actually meet at all. At the point where we would have had to go down on all fours and crawl to keep moving forward, the corridor ended at a letterbox-shaped opening about two feet high but stretching across the full width of the underpass. Just in front of it, on Trudie’s side of the corridor, a dark irregular mass resolved itself as we approached into a human body.
This was where the rotting-vegetable smell was coming from, and Trudie covered her mouth with her hand as she knelt to examine it. I crossed the tunnel to look over her shoulder.
The raincoat, piebald Doc Martens and grubby workmen’s trousers with pockets on the knees gave the overall impression that the body was that of a man; otherwise it would have been hard to say. He’d been dead a long time, which meant that rats and flies and the elements and the chemicals inside his own body had had their way with him. What flesh was left looked dry and mummified: one side of his face was staved in almost flat; from the other side, where most of the flesh had fallen or been picked away, the empty orb of his eye socket stared up at us with an expression of innocent surprise. He’d left no ghost to warn our death-sense that he was there, and mercifully he hadn’t risen in the flesh. There was nothing left of him except this sad ruin, and the smell.
‘Homeless guy,’ Trudie surmised, probably on the evidence of the boots. ‘How do you think he died?’
‘I think we can rule out natural causes,’ I said grimly.
I pointed to the tunnel wall above the man’s head. A dark stain on the tiles there had dried black, but with dark red highlights still visible here and there. It was shaped like an exploding firework, rising up on a slender column to blossom out in all directions. But the column had come last, of course. That was where the tramp had slithered down the wall after Asmodeus had slammed his head into it hard enough to shatter his skull.
It
was
Asmodeus; there was no reason to doubt that any more. The dead man might have left no echo of himself in this place, but the demon’s sickly essence hung around us now like a pall, and I knew it beyond all possibility of mistake. He hadn’t just passed through here; he’d lingered, and made himself at home. Trudie’s face showed that she felt it too. We’d struck the mother lode.
Without a word, we ducked and clambered through the narrow opening into a much larger space beyond. This was where the corridor ended, in a concrete wall about twenty feet ahead of us, but it came out beyond the road tunnel here, so it resumed its full height for this last stretch. What we were in was like a room whose only doorway was the one we’d just entered through.
It was even furnished, after a fashion. There was a grubby mattress on the floor, a sleeping bag on top of it, both of which must once have belonged to the poor bastard outside. In the near corner a dozen or so overstuffed carrier bags clustered like chubby little children cowering from an ogre: the dead man’s worldly goods.
But these melancholy, mundane details were pushed to the edges of my attention by the sight of the far wall, at which Trudie was staring open-mouthed. The chemical stench was stronger here. It was coming from a sprawl of pots and cans at the base of the wall, and from the wall itself, where Asmodeus had made himself busy.
From floor to ceiling, the space was covered with symbols, with words and with wards. The words were in Aramaic, so I couldn’t make them out, but the design was instantly familiar. A downward-pointing pentagram, with aleph sigils at the point of each arm and radiating lines fanning out across the negative spaces between the arms. Even if Nicky hadn’t listed those features for me, I would have known it. Whoever had drawn these designs had also left the unidentified wards in Pen’s drive, under Juliet’s hedge and on the roof of the Gaumont.
‘Tsukelit,’ Trudie spelled out. ‘Ket. Ilalliel. Jetaniul. Tlallik. Aketsulitur. Castor, do you know any of these names?’
For a moment I didn’t; they were just sounds. But then the thing that all the sounds had in common drove itself into my brain like a railroad spike. I’d been way, way off, and so had Nicky. The common denominator had never been me. ‘I know
all
of those names,’ I said, my mouth suddenly dry. ‘Or at least I know who they belong to. Jesus Christ, this is—’
The lights went out before I could finish the sentence, plunging us into absolute blackness. A whole second later, snaking down the corridor like a whiplash, came the chunking sound of the switch being thrown.
‘Fuck!’ Trudie gasped.
We were in the dark, half a mile away from the light switch, and we both knew who was out there, standing between us and the light, even before we heard the chilling boom of his laughter.
‘Run,’ I said tightly.
‘Run where?’ Trudie snarled. ‘We can’t see to run. Get out your whistle, Castor. Let’s give the bastard a fight at least.’
I found her arm in the dark, gripped it tightly and hauled her back towards the opening. ‘Not here,’ I said. ‘Not on his terms. He can see in the dark, Pax. If we stay here, we’re dead. Come on.’
She pulled back against me for a second, then gave in. We crawled on hands and knees back over the demon’s threshold into the corridor beyond. Trudie gave a sobbing cry of protest, which I took to mean that her hand had made contact with the corpse. I dragged her to her feet, though we still had to crouch, and set off at a stumbling jogtrot back up the tunnel.
It was hard to make myself move. I knew that Asmodeus was sprinting through the darkness towards us, fast and sure, homing on the smell of our souls. He could probably see us already, the way an eagle stooping over a meadow can find and focus on a fieldmouse in a square mile of tall grass.
‘Where are we going?’ Trudie demanded. ‘Castor, we’re going to run right into him!’
‘No we’re not,’ I muttered. I was still holding her wrist, but my other hand was running across the ceiling, fingers spread wide. When I couldn’t reach up high enough to touch it any more, I knew we’d gone too far. Quickly I retraced my steps, again yanking hard on Trudie’s arm. There! There it was!
‘What are you—?’ she demanded.
‘Here,’ I said, cutting across her. ‘Help me.’
It was the manhole we’d found earlier, the only way back up to the surface that didn’t involve getting past Asmodeus. Groping blindly in the dark, I’d finally found the outline of it, and now I put her hands on it too. ‘Push,’ I commanded.
‘It’s rusted shut!’
‘Try again!’
We braced ourselves against the tunnel floor, straightened our backs and strained against the unyielding cast-iron cover. The tunnel walls channelled a soft rhythmic sound to our unwilling ears: the sound of Asmodeus’s feet slapping the cobbles as he ran. It sounded like a barber stropping a razor.
My spine felt like it was breaking already, but I poured on the effort. Beside me, Pax growled low in her throat. The manhole cover didn’t budge by a fraction of an inch.
Pax moved away from me, and I heard her scrabbling around on the floor. Then I felt the vibration through the palms of my hands as she came upright again and drove something - one of the loose bricks that had been lying against the tunnel wall - repeatedly against the edge of the manhole cover. She was trying to dislodge the rust that had welded it into place, and it seemed to be working. It gave slightly, shifting against the pressure of my hands.
‘Push again!’ I grunted.
Trudie added her efforts to mine. With a squeal like a stuck pig, the manhole cover started to move. The light that rushed in was pale and washed out, but it was still startling. It showed the demon closing on us soundlessly in the dark, as fast as a torpedo.
With a booming clang, the manhole cover fell out onto the street. I grabbed Trudie before she even knew what I was doing, lifting her by her lower legs so that she had no choice but to grasp the rim of the hole and haul herself up. It was that or go over backwards into the dark.
Then I gathered myself and jumped, getting a grip on the edge and trying to pull myself up by my hands. My head cleared the rim of the hole, and I had a momentary, skewed vision of the road tunnel above: strip lights high overhead canted at a crazy angle, a soot-streaked crash barrier only a foot or so away, a car swerving around us and almost hitting the kerb. Trudie gripped my forearm and leaned back, using her weight to land me the way an angler lands a big fish. But something gripped my ankle hard and dragged me back into the dark. I clung desperately to Trudie’s arm, kicking out with my free foot but making contact with nothing more substantial than air. I went down heavily on my back, with a jarring impact that knocked the breath out of my body.
Asmodeus stood over me, grinning like the wicked land-lord in a melodrama. ‘It’s a mess down here,’ he said, conversationally. ‘You should have told me you were coming. I’d have made a bit of an effort.’
I scrabbled backwards, agonisingly aware that I was retreating not just from the demon but from the only exit. ‘You said . . . you’d save me for last,’ I reminded him, groping in the dark for something - anything - I could use as a weapon.
Asmodeus shook his head. ‘But you will keep putting yourself in harm’s way,’ he chided me gently. ‘What am I to do, Castor? I love our little talks, but I’ve got things to do and you keep tugging at my coat-tails like a kid who wants a lollipop. Anyway, I’m pretty much done here. Got all the ducks in a row. So I think I may go ahead and give you a spanking, just so you remember your place.’