The NecronomiPod beeps at me three times and drops the call.

"Fuck." I thumb-tap the software ward back to life, then shove the JesusPhone back in my pocket and keep jogging, breathing heavily now. There's a breeze in my face, shoving me back and slowing me down, and the surface of the footpath feels greasy and turgid, almost sticky. The sense of wrongness is overwhelming. I have a sense of deja vu, harking back to my midnight run, although that path was miles away and didn't look anything like . . .

Oh. Am I on a siding? I ask myself, as the headwind builds and the shadows deepen. I hear distant thunder and the first heavy slap of rain-drops on the path ahead: Did the Necropolitan line have branches that were edited out of the public record decades ago, by any chance?

The hoarse scream of a ghostly steam whistle echoes in my ears. It's behind me. And it's gaining ground.

It's funny how you lose track of a situation while it spins out of control: in the space of about fifteen minutes I've let myself be led by the nose—or rather, the feet—from a busy suburban high street in London, right into an occult trap. There are places where the walls of reality are thin; the service corridors of hotels, subway footpaths at night, hedge-mazes and cycle paths. You can get lost in such places, led astray by a lure and a snare and a subliminal suggestion. These routes blend into one another. Of all the myriad ways that link the human realm to the other places, these are the ones we know very little about—because those of us who stumble into them seldom return with their minds intact.

I can feel my heart hammering as I run. The hedges to either side brandish spikes edged with a nacreous rind of blight. There are pale white shapes embedded in the wall of leaves, the flensed bones of intruders trapped in the interstices of the vegetative barrier. Overhead, the clouds are black as smoke from the funnel of a racing steam locomotive, boiling and raging at the ground. I don't dare look back, even though I'm sure I'm being herded towards an ambush: the phone in my pocket is buzzing and vibrating in urgent Morse, signaling the presence of hostile intent.

I need to get off the path. The trouble is, there's nowhere to go—

Hang on, I think. Am I seeing true?