Whispers Under Ground

picked out the uncanny. In this case the vestigium was quite startling, like a shrieking voice, almost but not quite human. Like when cats fight outside your window and for a moment you can swear it’s a person screaming. Not once you’ve been police for any length of time, though – you soon learn to tell the difference.
    ‘Screaming,’ I said.
    ‘Is that a ghost?’ asked Lesley.
    ‘In a manner of speaking,’ said Nightingale.
    ‘A demon?’ I asked.
    ‘In the biblical sense of a fallen angel no,’ said Nightingale. ‘But it can be thought of as a spirit that has been driven into a state of malevolence.’
    ‘How do you do that?’ I asked.
    ‘Torture some poor soul to death,’ said Nightingale. ‘And then trap the spirit at the point of death.’
    ‘Jesus,’ I said. ‘Weaponised ghosts?’
    ‘The Germans invented this,’ said Lesley. ‘Didn’t they?’
    ‘Not invented,’ said Nightingale. ‘Refined perhaps. We believed that the technique is actually very old and originated in Scandinavia during the first millennia.’
    ‘Vikings,’ said Lesley.
    ‘Precisely,’ said Nightingale. ‘Bloodthirsty, but surprisingly erudite in a limited fashion.’
    Well that made sense, what with those long winter nights, I thought. Once you’d exhausted the possibilities of drinking, feasting and wenching, torturing someone slowly to death probably helped break the monotony.
    Nightingale handed me a stick.
    ‘I want you to bang gently on the carpet and find the edges of the device,’ said Nightingale. ‘Lesley can mark the outside with this.’ He handed her a piece of chalk.
    The stick was thirty centimetres long, knobbly and still covered in bark. It looked like something you might pick up while walking in the woods with a small annoying dog.
    ‘Very high-tech,’ I said.
    Nightingale frowned at me. ‘Wood is best,’ he said. ‘The greener and younger the better. Pull a branch off a sapling if you can. Much less likely to set it off.’
    My mouth went dry. ‘But this one isn’t live,’ I said. ‘Is it? You disarmed it?’
    ‘Not disarmed,’ said Nightingale. ‘Discharged and dissipated – think of it as a controlled explosion.’
    One that we’d ‘heard’ all the way across the river in Brixton.
    ‘But it’s inert now?’ I asked.
    ‘Possibly,’ he said. ‘But it was common for these devices to have two separate components, one to cause the initial damage and a second to catch any rescuers or medical teams.’
    ‘So be careful,’ said Lesley.
    I thumped the carpet a safe distance from the burn mark just to get a feel for what the normal floor surface felt like – concrete decking with a layer of hard insulator on top if I was any judge. I worked the stick back towards the centre until I felt it come down on something unmistakably metallic.
    I froze.
    ‘Find the edge,’ said Nightingale.
    I forced myself to backtrack until I was tapping concrete again. Lesley marked the spot with the chalk. I worked my way around the edge – it seemed to match the circular burn on the carpet but Nightingale said that you could never take that for granted. Once we’d established that there were no trigger pads outside the burnt area Nightingale handed Lesley a Stanley knife and we watched as she cut out a square of carpet and peeled it away.
    The demon trap was a disc of metal the size of a riot shield, the kind you use for snatch arrests. The metal was a dull silver and looked like stainless steel. At the centre two circles had been incised side by side. One circle was filled with a glittering sand that reminded me of what happened to microprocessors when they were exposed to magic.
    ‘I’m guessing that the empty one is the first component,’ I said.
    ‘Top marks, Peter,’ said Nightingale.
    ‘So the intact circle is the second component,’ I said.
    ‘What we call a double-boss device,’ said Nightingale.
    ‘What’s this scratched into the edge?’ asked Lesley.
    I looked where she was pointing and saw that there were marks etched neatly around the rim of the disc. Nightingale explained that they’d often found runic inscriptions on demon traps and the theory was that in the original Viking designs the runes had been part of the enchantment.
    ‘Like the Daoists?’ I asked.
    ‘Possibly,’ said Nightingale. ‘Comparative thaumatology is a discipline still in its infancy.’
    This was a familiar Nightingale joke – meaning that I was the only one currently interested in