‘No? Well, maybe you should be.’ It was Melissa talking, but Ben would never have known it if he hadn’t been following the conversation. He’d never heard her speak with such venom.

‘What’s that supposed to mean?’ Lance had clearly registered the change in her voice as well.

Melissa didn’t reply.

‘Melissa? I said, what’s that—’

Lance fell silent. Ben sensed something pass between them: a look, an understanding …

‘You already know,’ said Lance, after a pause. ‘Don’t you? Callum’s already told you how this is supposed to end.’ He sounded shocked. Afraid, even.

‘Oh, please,’ said Melissa. ‘Don’t pretend that you don’t know, too. That you haven’t known from the start. You said it yourself: there has to be more. Why do you think we needed somebody else in the first place? Or why Callum wouldn’t let you do it?’

Ben heard footsteps approaching the door. They were shuffling, hesitant, as though Lance were backing away. Ben cast around, looking for cover. There was a cupboard in the corner closest to him, and he ducked into the gap between the unit and the wall. The space was barely big enough, and if Lance turned his way when he stepped out of the darkroom, he would surely see him. But when Lance appeared he was shaking his head, staring back into the darkness.

‘I meant what I said, Lance,’ came Melissa’s voice, and Ben could tell she’d followed Lance towards the threshold. ‘If you don’t want to be a part of this, fine. Go tell Callum. See what he says. But if you go blabbing to anyone else, I swear to God … it won’t just be Callum you’ll need to be afraid of.’

Friday 25 October, 3.36 p.m.

Sicut serpentes, sicut columbae.

Fleet was in the car on his way back from the school, and the words kept playing in his head. It was like the line of a song that had snagged.

Sicut serpentes, sicut columbae.

He could picture the engraving of Beaconsfield’s coat of arms in the building’s entrance hall, and see the motto that was inscribed beneath it. ‘Wise as serpents, innocent as doves’ was how he’d initially translated the Latin, but there was another possible translation as well, he knew – substituting wise with cunning.

As he squinted through the rain that was hammering the Insignia’s windscreen, it occurred to Fleet that maybe he’d been thinking about things the wrong way round. He’d gone to the school intent on finding out more about the fire, but maybe it wasn’t the blaze itself he should be focusing on – rather the fact that whoever started it had got away with it without being caught. Maybe that was the source of inspiration Callum Richardson had been referring to.