I didn’t know what to say so I said nothing. After a few minutes I heard Charlotte’s breathing fall into the rhythm of sleep. I tried to follow suit, but there were so many thoughts going around in my head. I’d assumed so much. I’d assumed Charlotte was naturally smart and possessed of a brilliant memory. It hadn’t occurred to me that maybe she was forced to spend countless hours alone in this room just to give that impression. I’d assumed her parents were wealthy – not as wealthy as mine, naturally – but wealthy all the same. How else could they have afforded to send her on that ill-fated camp? I realised I had no proper understanding of how the world operated. Maybe Aiden was right. Maybe the Delatour family was determined to keep the ugly world at a distance so we couldn’t be offended by it.

I eventually fell asleep, but my dreams were fractured and restless.

I was woken by a siren in the middle of the night. It made me jolt upright in bed, my heart hammering. Charlotte barely stirred. Her eyes flickered open and she put a hand on my arm.

‘It’s okay,’ she mumbled. ‘Go back to sleep.’

‘What is it?’

‘Just an alarm from the wall. Happens all the time. Dad and his men will sort it. Go back to sleep.’

But I couldn’t. Even when the noise stopped, about half an hour later, I couldn’t. I stared at the dark space above the bed, listened to the silence and waited until morning slowly bathed the room in light.

Charlotte’s theory about puberty explaining Aiden’s mood swings and strange behaviour had stayed with me. I tried to tackle him about it the following day, after dinner (it featured chips – Mum was away on yet another conference).

‘Do you feel all grumpy, Aiden? Maybe a bit depressed? Feeling like you aren’t in control of your own body?’

‘Your face is all grumpy,’ he said. And smiled. This was something we’d seen in an old movie. This character kept saying ‘your face’ when replying to a question. It was really stupid and childish and we’d stopped doing it ourselves a year or so ago. We’d just forgotten about it. I was amazed – and curiously pleased – that it seemed to have made a reappearance.

‘I’m serious,’ I said.

‘Your face is serious,’ said Aiden. ‘And your face is depressed.’

‘It is now I’m talking to you.’

‘Ha, ha, good one, Ash-face.’

‘Your face is an ash-face,’ I said and we both cracked up laughing at that.

So he never did confirm Charlotte’s diagnosis, but the fact that he was in such a good and talkative mood seemed to indicate she was on the right track. He’d been so intense the night before last. Scarily so. I could almost hear those hormones racing through his body.

I felt both of us were in for a tough time of it for the next couple of years.