‘It’s a ransom note, Jack, threatening to hurt your mother,’ said Xander. ‘The first thing we need is adult advice.’

This made good sense, yet something in me resisted. ‘Immediately is a pretty clear instruction,’ I said. ‘What if they’re monitoring me somehow. If they think I’m disobeying them and take offence –’

‘Xander’s right,’ said Amelia firmly. ‘This is Langdon’s brother and sister-in-law we’re talking about. He’ll want to know they’re in danger right away. There’s no evidence anyone’s “monitoring” you anyway.’

Amelia’s fingertips made air quotes around the word monitoring. It annoyed me. While she was right that I had no concrete evidence I was being observed, that didn’t necessarily make me wrong. Either way, I felt wary. Amelia knows a lot and thinks logically, but I’d trust my gut instinct over hers any day.

I read the note again slowly. It told me not to contact the police again, but didn’t say anything about anyone else. Amelia and Xander were obviously sensible to suggest I call Langdon, and I would. But the note was addressed to me. It concerned my parents. And it said to call the number at the foot of the page immediately. ‘Thanks, guys, but this is my decision,’ I said evenly, and pulled out my mobile phone.

35.

Nobody picked up.

I’d entered the number carefully and double-checked it before pressing call. I was expecting whoever was on the other end to answer immediately, but they didn’t. The phone rang for what seemed like ages. Sometimes, if I glance at a clock with a second hand, anticipating seeing it move, the second it should take to tick seems to take forever precisely because I’m waiting for it. Waiting for the kidnapper to answer my call felt a bit like that that, with the waiting stretching time improbably, so much so that I almost hung up. But in reality the delay was probably just the normal length of time it takes for voicemail to kick in, and just as I was about to take the phone away from my ear to end the call, that’s what happened. An automated, sat-nav type woman’s voice said the following simple sentence.

After the beep please say your name. We will contact you with further directions shortly.

I did as instructed without knowing why, and explained to Xander and Amelia what had happened.

‘Why would they get you to do that?’ asked Xander, echoing my bafflement.

‘Isn’t it obvious?’ said Amelia. ‘They don’t have his number. Or they didn’t until now.

‘Fair point,’ said Xander.

‘They want to take control. By getting you to confirm you’re Jack Courtney, they know it’s you they’re calling back, and they can do that at a time and from a place that they choose.’

‘Makes sense,’ I said.