I’ve made it to Chesterton Road, hauling the tin tub and everything else, and I’m dripping with sweat. It’s not that far, maybe a mile, and I’ve gone down back lanes when I can and generally tried to be unobtrusive.

That is, as unobtrusive as a boy running and carrying a huge garden tub can be.

From a few streets away I hear a quick blast from a police siren. I guess they’re patrolling the streets looking for me by now, but it’s hardly a full-scale emergency. Yet.

It’s a warm evening, and the air is a bit salty from the sea. The trees that line the street cast long shadows and I can hear birdsong and a lawnmower. Not that I’m noticing it much. I don’t think you would, either, if you were going to do what I am going to do.

So I’m jogging down Chesterton Road with the tub and everything, past Mr Frasier’s monkey-puzzle tree, across the alleyway that leads down to the seafront, and then I’m at the ‘jungle’, among the scrubby bushes, and dried-up litter and bits of twig.

I don’t know why, but I choose exactly the spot where Carly did her mirror-and-candle thing. Like I say, it just feels right. It’s as if I’m carrying out some ritual.

The battery on the laptop is charged, and I carefully place the leads and the hand grips over the edge of the tin tub so they are touching the bottom. The black box (which I never did find a proper name for) is connected to the laptop, and the memory stick is jammed into the side when I turn it all on and it begins its start-up.

You know, I think at a point like this it is usual to say that my heart was ‘beating like a hammer’ or something like that, but mine isn’t. My mouth is a bit dry, I suppose, but that could have been from the running, and I’m sweating because it’s a warm night, but my heart? Nah.

I think it’s because I simply have nothing left to lose, and nothing more to give.

From my jeans pocket I take the letter to Pye and place it with both hands, sort of ceremoniously, in the tub as well. I pick up Alan Shearer and hold him close to my face. His whiskers twitch and I give him a little kiss on his furry back.

“Good luck, matey.” Into the tub he goes. He seems happy enough.

The numbers have stopped their scrolling and the blurry sheen has appeared, by now much less than halfway up the side of the tub, but still well clear of Alan Shearer’s head. There are just the coordinates to enter. Cautiously, I open up the folder marked ‘map’. I’ve only opened up this folder once before and it looks scary: right now it’s showing a stark bird’s-eye view of the streets around Culvercot in green and black, like Pye’s old computers in the school. (I think it’s been adapted from Google Maps or something, and laid over with a kind of grid.) Using the touchpad, I pinpoint the exact spot where Grandpa Byron’s shed is. When I click, up pop the coordinates for me to enter. That is where – all being well – Pye will discover a tin tub, and a letter, and a hamster.

Then the date and time.

And then the password. I hum The Blaydon Races to help me remember.

WMAG GGGGWV E7G5 EGL2 CWG

I have told myself on the jog here that the most likely thing is that nothing will happen. It’s because of the doppelganger thing. I’m not travelling anywhere; I’m staying put, right here, so I can’t meet my own double. But I am hoping that my letter changes the past. I’m hoping that Pye will live, and go on to meet Mum, and have me … and then what? Will I have somehow slipped under the barrier of spacetime, broken its rules, and come face to face with the ‘me’ that up till now has been living an unremarkable life with Mum and Dad? I’m hoping not …

But I can’t be certain.

So with all this going on in my head, finally – with … with what? A trembling finger? Nope. My heart in my throat? Nope again – I just press ‘enter’.

Just like that.

Like I say, I have nothing left to lose.