To be fair to him, he broke into a trot once he got himself orientated up the hill, and although I lost sight of him he was quickly outside the door, fighting to open it. The lock defeated him at first, but having shouted that he’d be back immediately with help, he summoned a key quickly too, and I could hear him giving whoever he’d got hold of a hard time: ‘Quick, you moron. When my father hears about this, the fool who thought it was a good idea will regret it.’

Marcel didn’t break from his statue-like trance until the key turned in the lock. I’ve never been so happy to see a door open. The rush of air felt positively cool compared to our little oven. The first thing I saw was Caleb pushing the security guy away, hard. That was surprising enough, but nothing compared to the expression on his face when he turned back to greet us. In the few days we’d been apart, it seemed the stuffing had been sucked out of my cousin. He looked gaunt, bloodlessly pale. Also, the shape of him had changed. Gone was the puffed-out chest and high chin; in its place was a stooped, rounded thing. He couldn’t meet my eye.

‘Guys,’ he said, inspecting the dirt between our feet. ‘I’m so sorry.’

‘Why?’ said Amelia. ‘You didn’t lock us in here. You got us out.’

‘I know but …’ he petered out.

‘Without you we’d probably have cooked in fact,’ Amelia went on, desperate to cheer him up. ‘So you’ve literally saved our lives.’

‘Someone else would have come eventually,’ he said.

‘Maybe, but nobody had until now. I’m not sure how much longer we’d have lasted.’

Caleb was shaking his head, eyes still fixed on the floor. The penny dropped for Amelia. She changed tack. ‘Oh, so the sorry isn’t about your father’s security detail locking us in here. Well, at least that makes sense. But what else do you have to apologise for?’

A horrible thought flashed through me: did he know something about Mum and Dad? I opened my mouth to ask, but before I could get the question out Caleb glanced up at Marcel, shook his head and said two words: ‘For Innocent.’

I’m ashamed to say it, but instead of sadness in that moment I felt relief. If this new hollowed-out version of Caleb meant that he actually felt guilty about Innocent’s death, then good. It was what he deserved.

‘But that was an accident!’ Amelia said a bit too loudly. She meant to reassure him, but the false brightness in her voice made it obvious she knew the ‘accident’ could have been prevented. Nevertheless, she stepped forward and put an arm around Caleb’s hunched shoulders to comfort him.