I don’t know how it happens. One second I’m hobbling along the path, glancing to my left at the sound of a police siren coming up the road — and momentarily feeling that I’m somehow looking down on myself from above — and then all at once the ground isn’t there anymore and I’m falling.

For a moment, all I feel is the tingled shock of my innards lurching upward as I drop down through the air, and then — before I’ve had time to work out what’s happening — I hit solid ground again, landing heavily on my side, and then I kind of flip over a couple of times and start plummeting down the steep-sided slope of the valley — slipping and sliding, tumbling, rolling . . . picking up speed all the time . . . careening down through a whirling darkness of ground and sky and trees and snow and rocks and spinning limbs . . . desperately trying to grab hold of something, my gloved (but cold and wet) fingers scrabbling blindly at the frozen ground . . . grasping at brambles, roots, half-buried rocks . . .

I don’t know how long it takes before the slope finally starts to level out — it feels like I’ve been falling forever — but it’s probably only been about ten seconds or so. The change in the gradient is quite gradual at first, but even when it really starts flattening out — becoming an almost walkable incline — the speed of my descent doesn’t change. I’ve built up so much momentum that I just keep hurtling down . . . rolling over and over, skidding along on my back . . . clothes ripping . . . skin scraping . . . elbows and knees and my head bouncing off God-knows-what . . . but eventually I feel myself beginning to slow down, and instead of just tumbling and rolling uncontrollably, I somehow manage to get myself into a half-sitting-up position, so now I’m sliding down on my backside, with my elbows digging into the ground at my sides, and my legs stretched out in front of me. I’m still moving too fast to stop myself, and it still hurts a lot, but at least I’ve got some control, and I can see where I’m going at last . . .

I can see . . .

There’s a light.

It’s shining out at me from the wooded darkness ahead — a concentrated beam of bright white light — and as it slices toward me through the solid black air, I catch a fleeting glimpse of the area immediately in front of me. At the foot of the slope — just a few yards below me now — a short stretch of gently sloping ground leads down to a massive slab of granite embedded in the earth above a pathway. It’s like a giant stone step — about ten yards long and five yards wide — and at the far end, it looks as if it just drops straight down to the pathway below. I can’t actually see the ground directly below it, but I can see enough of the pathway on either side to guess that it’s a drop of about one and a half yards.

On the other side of the snow-frosted path is the woods, which is where the light’s coming from.

I see all this in an instant.

And an instant later, I hit the ground hard, feetfirst, and my forward momentum sends me staggering across the gentle slope and onto the granite slab, my arms windmilling as I try to stay on my feet, but it’s always a losing battle, and just before I reach the end of the slab, I finally overbalance and go sprawling forward with my legs flying out behind me . . . and I know I’m not going to make it now . . . I can see the edge of the slab looming up at me as I stumble helplessly toward it, and I can see the path below . . . and at the very last moment — just as my right shoulder crashes down hard on the granite edge — I think I see the light in the woods moving toward me.

My right side clips the edge of the slab as I fall — a glancing impact that spins me over — so when I drop down to the path I’m facing upward, and I land with a bone-jarring thump on my back that knocks all the wind out of me.

I don’t move for a few moments, I just lie there with my eyes closed, gasping for breath, trying to work out if I’m seriously hurt anywhere or just battered and bruised all over.

I hear something then, a close-up sound, right next to my head — a heavy footstep crunching in the snow — and when I open my eyes all I can see is a blinding light shining down into my face.

As I raise my hands to shield my eyes from the dazzling light, I hear a voice from above. It’s a male voice, and there’s a smirking menace to it that makes my blood run cold.

“Well, well,” it says, “what have we got here?”