60.

That turned out to be easier than expected, partly because they didn’t go far. We were only travelling for about fifteen minutes. Still, it was time enough for the sun go down. I didn’t turn on the bike’s headlight. This was helpful, since when the truck pulled to a stop in a half-built neighbourhood made up of what looked like factories or warehouses, I was able to drift to a standstill behind a van parked on the other side of the road without attracting attention.

‘Check that out,’ said Amelia.

I was shutting down the bike, rocking it onto its stand. ‘What?’ I said, peering round the back of the van.

‘Them.’

Two men carrying guns had approached the newly parked SUV. When Langdon and his driver stepped down from it, one of the men backed away, an eye on the street, while the other holstered his pistol and stood before my uncle. Langdon’s driver handed something over to the guard with the holstered gun. It was a cooler box. Langdon and the guard talked for a moment, Langdon with his hands on his hips, the guard with his arms respectfully at his sides. I couldn’t hear anything over the hum of the invisible city, not until Langdon threw his head back and laughed. Something in that gesture caught in my throat.

‘Are you thinking what I am?’ I whispered.

‘I don’t know,’ Amelia said, baffled. ‘What are you thinking?’

‘Armed guards. A warehouse in a wasteland. Langdon delivering whatever he’s delivering. A cool box. So, food, possibly?’

‘Those aren’t thoughts – they’re observations and guesses.’

‘Adding up to?’

‘The obvious possibility that your parents are in there.’

I turned to her.

‘The important word is possibility,’ she said patiently.

‘I disagree. It’s obvious.’

‘Another of your hunches is what it is.’

She was right, but this hunch was all I had.

Langdon raised a forefinger and wagged it at the guard, then spun on his heel. The wedge of light from the security lamp caught the side of his face. There was an odd shadow across his cheek. A bruise, I realised, as he stepped beyond the light and back to his car. I pulled Amelia behind the van, heard the growl of the SUV starting up again, watched its red tail lights bleed out down the street.

‘What now?’ Amelia asked.

‘I don’t know!’ I said. ‘Let’s watch for a while. See what those guys with the guns do.’

The answer to that was: not much. Occasionally one of the men would amble across the floodlit forecourt, but then he’d simply stroll back to his position on one side of the building’s roller-door entrance, which stayed firmly shut. There was no apparent pattern to these movements. It just looked like two bored guards keeping themselves from falling asleep by making a show of walking around.

‘I want to check the building, see if there’s a rear entrance, or a window I can reach,’ I whispered.

‘Yeah, but to do that you’ve got to cross beneath the light,’ Amelia said. ‘They’ll see you.’

She was right, but there was one solution: put out the light.

‘Reckon you can drive the bike?’ I whispered.

‘I’ve only been watching you and Marcel do it for about a hundred hours. How could I possibly have learned?’

‘OK, OK. When I say, drive it straight to the first junction down there. It’s about four hundred metres away if I remember rightly. Anyone follows you, keep going. If not, wait for me there. OK?’

‘I should be able to manage that. But what are you going to do?’

‘You’ll see. Or rather you won’t. Shut your eyes.’

‘Why?!’ she hissed.

‘Just do it. And keep them shut. It’ll make sense in a minute.’

‘OK.’

We were crouched low on the verge behind the van, on scrubby wasteland. I fingered the dirt blindly in search of a decent-sized stone, thinking, You’ve got one shot. The floodlight was on a pole in the middle of the forecourt. Miss it and the stone, thrown from here, would slam into the front of the warehouse. A guard wouldn’t have to be a genius to work out where it had come from.

So don’t miss.

My hand closed over a solid chunk of something that felt like broken brick. It would do. I couldn’t risk stepping out from the cover of the van. Flinging a rock takes an explosive movement, which the guards might spot. Instead I moved carefully backwards until the security light rose above the top of the van. It looked alien, a one-eyed monster rearing up. I was a good ten metres further from the target back here, putting it at the very limit of my range. Was there a less risky solution to this problem? I couldn’t think of one, didn’t want to think of anything in fact, just took a deep breath and imagined myself in the yard at school, taking aim at the top chimney pot. The trick, at this distance, was to aim well above the target. I had hit that pot before, and I would put this monster’s eye out now, or else.