‘You’re off your head,’ said Zach. ‘It’s made by the Quiet People, not in some factory in China.’ He spoke slowly to make sure I understood. ‘So each one is different like someone’s face is different – that’s how I can tell them apart.’

I wondered if Zach, half fairy, half goblin, half whatever he was, perceived vestigia differently from the way me, Lesley and Nightingale did. If he did, then it would make sense for him to also respond to it differently, perhaps less powerfully. I made another note for later because I knew Lesley would homing back in on the policing.

‘Moving on,’ she said, right on cue. ‘So you took James Gallagher through the sewers to meet these “quiet people”?’

Zach smiled at her. ‘You can take your mask off, you know – we don’t mind. Do we, Peter?’

I expected Lesley to either ignore Zach or slap him down, but instead she turned to me and gave me an inquiring look.

‘You don’t have to ask my permission,’ I said, half hoping she’d leave it on.

She looked at Zach, who gave her a crooked smile.

‘I’ll take it off,’ said Lesley slowly. ‘If you stop messing us about.’

‘Okay,’ he said without hesitation.

Lesley unclipped her mask and slipped it off. Her face was as horrible as ever and glistening with sweat. I froze for a moment and then thought to hand Lesley some tissues. As she wiped her face I realised that Zach was staring at me – eyes narrowed.

‘The mask is off,’ I said. ‘Your turn.’

‘James Gallagher and the seven dwarves,’ said Lesley.

‘Did I say they were short?’ asked Zach.

We both just stared at him until he got on with it. James, Zach told us, had been persistent in the way that only Americans and double-glazing salesmen seem to be capable of. No matter what Zach said or did, including storming out of the house and all the way down to the off-licence, James wouldn’t let up.

‘So we got some gear together and down the rabbit hole we went,’ said Zach.

A rabbit hole with a horrible smell. I got Zach to pinpoint the exact manhole they’d gone down on a printout of Google Maps. Shockingly, it was located fifty metres up the road from James Gallagher’s house. I wondered if it was the same one that Agent Reynolds had found.

There was a certain amount of farting about as we showed him the boots and he agreed that, yeah, they were James’s boots or at least they looked like the boots James bought for going down the sewers, I mean they could be somebody else’s, couldn’t they? It was not like he was paying a lot of attention to James’s boots – that would be bare strange, wouldn’t it?

‘Unless you’re into boots,’ said Zach. ‘Takes all types.’