I gingerly undid my coverall and felt my chest. The Metvest was still intact but there were three holes in the nylon covering. They were ragged with blackened edges – like cigarette burns. Something dropped from my chest and pinged off the cement floor. I picked it up – it was a pistol-calibre bullet.

‘That’s odd,’ said Reynolds, who’d sat up to take a look. She held out her hand and I dropped the bullet into it so she could examine it more closely. ‘Nine millimetre. It’s barely deformed at all. Are you sure this hit you?’

I winced as I felt the bruises under the vest. ‘Pretty certain,’ I said.

‘This one must have gone through the water first,’ she said.

I found it remarkably easy not to tell her that it was more likely that the bullet had been slowed by the magical force field I’d conjured up.

‘I don’t know what happened to the lamps,’ said Kumar. He’d detached his helmet lamp from its bracket and was prising off its back.

‘Maybe they’re not as waterproof as we thought they were,’ I said.

Kumar frowned down at the lamp, but LEDs, like most solid-state technology, look the same whether they’re broken or not. ‘Never happened before,’ he said and gave me a suspicious look.

I looked away and noticed that Reynolds was still shivering.

‘Are you cold?’ I asked.

‘I’m freezing,’ she said. ‘Why aren’t you?’

I explained that we were wearing wetsuits.

‘They didn’t have those at the embassy thrift store,’ she said. ‘I had to make do with Marine hand-me-downs.’

I’d like to have asked what had brought her into the sewers in the first place, but her face had gone very pale. I’m not privy to the media policy directives of the Metropolitan Police, but I suspected that from a public relations standpoint a dead FBI agent would be way more embarrassing than a live one.

‘We need to find somewhere for you to dry off.’ I said. ‘Where’s your backup?

‘My what?’ she asked.

‘You’re an American,’ I said. ‘You guys always have backup.’

‘Times are hard,’ she said. ‘And resources are limited.’ But she looked away when she said it.

Ah, I thought. She’s playing that movie – the one where the pen-pushers block the hero from getting involved and she goes rogue to solve the mystery herself.

‘Does the embassy know you’re down here?’ I asked.

‘Never mind me,’ she said. ‘Where’s your backup?’

‘Never mind backup,’ said Kumar. ‘Where are we?’

‘We’re still in the sewers,’ I said. ‘We just need to find a way out.’

‘What are our options?’ asked Reynolds.

‘Well, we have hole number one,’ said Kumar. ‘The ever-popular floodwater relief sewer. Or we have a dark and mysterious doorway.’ He struggled to his feet and went over to peer inside.