Slowly Ben’s outline began to emerge, but even as the darkness all around them faded to grey, another, deeper black began to creep in. It was like being in a tunnel that was slowly constricting, and Isaac knew he was on the brink of passing out. He tried pulling at Ben’s fingers, but it was like trying to prise apart a vice. Instead Isaac flailed, feeling for something, anything, that might help. His hand closed around something hard – a rock? a piece of rubble? – but as he struggled, he lost his grip. He found it again, dropped it, and the third time he clasped it tight. And then he swung – once, twice – with everything he had, aiming the stone at Ben’s head.

The sound it made was sickeningly soft, like a melon being hit by a hammer.

Ben immediately rocked backwards, and for a moment Isaac thought he was free. Yet before he could even draw breath, Ben was on him again, impossibly, and clawing once more at Isaac’s neck. This time Isaac reached out as well. His fingers found purchase, and he latched on tight, squeezing with all his might. And he kept on squeezing, squeezing, until he realised he was breathing freely, and the hand that had tightened around his own throat had long since fallen away.

Sunday 27 October, 10.52 a.m.

It was the mention of his son that finally roused the headmaster from his stupor.

‘Isaac?’ he said. ‘Isaac did this?’ He looked around at the burning buildings. ‘But … why?’

‘To get to Richardson,’ Fleet replied. ‘He wants to punish him, the way he punished Melissa and Lance.’ Quite why, Fleet wasn’t sure yet, but it was clear that Isaac blamed them for what had happened.

‘I know you loved Isaac, Mr Harris,’ Fleet said. ‘I know you never stopped loving him. That’s why you’ve been here for as long as you have. Isn’t that right?’ He had the headmaster’s complete attention now, but he didn’t wait for him to answer. ‘I thought at first that it was just about protecting the school for you. I even wondered if you might have been covering for Richardson, safeguarding his family’s donations. But it was never about either of those things, was it?’

From Fleet’s very first encounter with Adrian Harris, the man had stood as proud and unyielding as an oak tree, his demeanour a parody, almost, of how a head teacher at an elite private boarding school was supposed to present himself. Amid the smoke and the heat from the burning chapel, the facade he presented had begun to crack, but there was a flash of the old headmaster in his reaction to what Fleet had said.