‘Straight lines. Mostly around Holborn, which is one of our secondary clusters. See, he’s going either north or south here, but he doesn’t cut to the left to go into - whatever that is, Old Gloucester Street. He keeps right on going. Walking through walls. Making like the street grid doesn’t matter to him. Which it doesn’t.’
‘Because he’s underground,’ I finished.
Gil looked annoyed that I’d got to the punchline ahead of him, but all I was doing was joining the dots. It was still his insight, and I was impressed. Jenna-Jane was right: he was a good exorcist and nobody’s fuckwit.
‘Or flying,’ Trudie added scrupulously. ‘We didn’t want to rule out the possibility that he might be able to transform himself somehow.’
‘But in that case,’ Gil broke in again, ‘we’d be seeing straight lines all over. We don’t. They’re just in the centre. So he’s got an underground route that takes him through just this stretch here.’ He indicated with a broad sweep of his hand an area that extended from the river up almost as far as Russell Square. ‘The next question is why does he use it? I mean maybe it’s quicker, but not by much. And he’s not afraid of bumping into people. If he’s got to go over-ground for most of the time, why use this one little stretch of tunnel that he’s found? And why keep going back to it?’
‘He’s got a base there,’ I said, playing straight man again. ‘This is where he hangs his hat.’
‘And that,’ said Jenna-Jane, taking charge of the proceedings again, ‘is the conclusion we’d reached just before you arrived. The puzzle that remains is to determine what tunnels he’s using. The London Underground network seemed the likeliest option, given the density and depth of the tunnels in the centre of the city, but there’s no obvious candidate.’
‘We got hold of some maps from the city engineers department,’ Samir said. ‘They give a pretty exact mapping of the tunnels onto the streets above. The Piccadilly Line goes up here, about a hundred yards east of this nexus of main roads. The demon’s path veers west, if anything, so it’s not that. Central Line’s too far down . . .’
‘He wouldn’t be likely to use tunnels that are actually in use in any case,’ I pointed out. ‘Too risky and too inconvenient. Do the inspection tunnels follow the same plan?’
‘Not exactly,’ said Trudie, ‘but they run parallel with the main line and they’re still too far out.’ She showed me some red lines traced on the map a long way from the black flecks that marked the demon’s comings and goings. ‘We thought of disused stations too,’ she added, forestalling my next question. ‘No joy. There was a lot of old digging around King’s Cross and the Angel, and some of those tunnels extended quite a long way to the south and west, but he’s not following the line of any of them that we can see.’
‘So now we’re working on sewers and sealed-off waterways, ’ Gil grunted. ‘Which could take us days, because there are literally hundreds of miles of them to cover, and the maps don’t always correlate to street level except at known access points.’
‘Any insights, Felix?’ Jenna-Jane coaxed.
I stared hard at the map: at the way the black flecks siphoned into High Holborn and Kingsway and then splurged outwards again at Waterloo Bridge. I tried to imagine myself walking that route, as I’d done a thousand times. Down Woburn Place, past Russell Square Gardens, into Southampton Row . . .
‘No?’ J-J seemed disappointed. ‘Well, then I suspect you work on two fronts, Gilbert. Keep someone here, adding the sewer and waterway information to the map grid, while the rest of your people go out and walk the ground. Assuming the demon has gone to ground for the day, we might get a current time fix on him just by being there.’
McClennan became brisk. ‘Teams of two,’ he said. ‘Cartwright and Powell. Greaves and Etheridge. Devani, you can come with me. That leaves you and Castor on the map, Pax. Let’s move.’
He probably thought that grounding me would piss me off. It probably would have too, if I intended to do as I was told. I wasn’t done with Gil yet though, and I stepped into his path as he headed for the door.
‘We need to talk about Super-Self before you go anywhere,’ I said.
He stared at me, deadpan. ‘That’s all in hand,’ he said. ‘If you’re looking to clock up some overtime, Castor, you can forget it. I don’t want you, and more to the point I don’t need you.’
‘You might want to know what you’re facing, all the same,’ I said. ‘And you might need this.’ I held up the key to the gym’s front door. McClennan recognised it at once, or maybe just guessed what it was. He took it out of my hand, looked at it thoughtfully for a moment, then nodded.
‘You’ve got your assignments,’ he said to the other exorcists in the room. ‘Get moving. Samir, wait for me downstairs.’
‘I’d rather make a start,’ said Samir.
Gil didn’t even look round; his eyes were locked on mine. ‘Make a start then,’ he said. ‘I’ll call you when I get over there.’