‘I know a way we can find out for sure where those trees have come from,’ Karim says, stepping out into the open.

121 Before I can even get my head around what he’s doing, he runs to the truck and climbs into the cab.

‘He’s not going to try to drive that truck, is he?’ Kat squeaks through her scarf.

‘I honestly don’t know,’ I say, starting after him.

By the time I get to the cab, Karim is already jumping back out. ‘We’d better run,’ he says, darting towards the gates.

‘Hey!’ I hear a shout behind me, and the crunch of footsteps on gravel. ‘Stop right there!’

Of course, that makes us move faster. The gates are just ahead and open wide – we only have to get there. And then they start to close.

‘Oh man,’ I say. ‘They must be operating them from the office.’ We’re not going to make it. ‘Plan B – back into the trees!’

We turn sharply, and speed into the Christmas trees, smashing through the branches and plummeting into darkness. I hear shouts and heavy footsteps following me, and I lose track of Karim and Kat. I turn my head from side to side, trying to catch a glimpse of them, but all I see are shadows. Shadows, and branches that pull at my clothes and scratch at my face. An arm jerks 122 towards me from between two trees on my right, clutching at my sleeve and holding tight. I pull away as hard as I can, but the hand feels superglued to my arm. So I kick out with everything I’ve got, making contact with something that I hope is a leg and not a tree trunk. I hear a grunt, and the hand tears away from my coat with a ripping sound, so I run again, crashing through the trees. A person-shaped shadow looms out of the murk in front of me, so I make a sharp turn to the left, while at the same time shoving a ceiling-high tree towards it.

At the side of Verge’s garden centre there’s a separate building that sells pond stuff – weed and rocks and loads of different fish. I used to visit it for a Sunday treat when I was younger, spending ages watching the koi shimmer around their pool. It has a small exit that leads straight into the car park. Now it’s our only option.