I knew better now than just to ask outright what that job might actually be. That the Authority wanted to retrieve data related to transfer stage technology from an alternate Iceland made at least some kind of sense, but the thing I couldn’t work out was what possible reason the Authority might have for wanting anything to do with how the bee-brain chimera had been developed. Even though Yuichi and others had warned me not to get too hung-up trying to figure out the ultimate purpose of all the missions the Authority sent us on, I couldn’t let it go. Either I found out at least part of the truth, or I descended into the same incipient or full-blown alcoholism already afflicting many of my fellow Pathfinders.

‘Maybe they’ll put Mayer in charge,’ Haden suggested. ‘He’s more or less running everything here as it is, Bramnik’s away so much.’

Yuichi was about to say something else when Mayer beckoned us over. We joined him and the tourists, and Mayer got Casey to answer some of their questions while the rest of us hung back.

The Australian grinned toothily, and began to speak.

‘I’ll give him this,’ I whispered to Yuichi. ‘He’s good. Maybe he should have been on TV.’

‘He was,’ Yuichi whispered back. ‘He used to make wildlife documentaries back on his alternate.’

I listened as Casey told his audience all about the work we did, and about two other non-Pathfinder teams currently on stand-by in other parts of this alternate, ready to take measurements once the impact took place, following which they would escape via their own transfer stages. Casey was, indeed, an excellent raconteur, and I found even myself drawn in by his description of how we did our work.

After a few minutes of this, a soldier stepped over to Mayer and spoke quietly in his ear. ‘That’s it,’ said Mayer, raising his hands until he had the undivided attention of everyone in his audience. ‘Everyone get ready. Impact in just five minutes. If you’d care to follow me, I’ll run through the safety procedures one more time . . .’

I watched as the tourists followed Mayer over to where two other soldiers were busily setting out folding deckchairs. The tourists all sat, facing east in the direction of the impact zone. The scene struck me as entirely surreal.

In the meantime, Casey had hauled a shoulder-mounted video camera out of a bag at his feet, before propping it on his shoulder. I watched as he fiddled with its controls, slowly sweeping the lens from one horizon to the other and frowning and mumbling to himself before making yet more minute adjustments to the camera settings.

From somewhere on the streets below us came the rattle of automatic gunfire and the screech of numerous cars accelerating hard. Then I heard screaming, the sound raw and ragged and echoing from the walls of the buildings around us.