Above that cap, made of high-density concrete and steel girders, was a vertical shaft, now filled with a couple of thousand tons of rubble and sand. It was a defensive measure, or so I had learned from flicking through Schultner’s mission-briefing pack. The Icelanders had been aware of the threat of invasion by those less prepared for survival on a hostile Earth and, like the pharaohs of old, they’d filled their subterranean kingdom with booby traps. Explosive bolts in the concrete cap could blow it apart, and the steel girders that helped hold all that rock and sand were designed to give way once the bolts blew. In this way a vault could be sealed off, either keeping invaders outside, or trapping them on the inside. I saw two sets of ladders bolted to the wall on either side of the corridor, each leading up to one side of the cap. What a shame their front door hadn’t been strong enough to withstand a tactical nuke.

The ground began to shake again. But instead of fading, the shaking grew stronger.

I helped attach the cable from our EV to the rear axle of the ditched vehicle. The cable was slightly bent where it went around and between fallen girders. The stricken EV’s rear was angled upwards, its wheels hanging uselessly above the ground. The front chassis was invisible where it had slid into a huge crack in the vault’s floor.

‘Jerry!’

It was Nadia’s voice, but I couldn’t figure out which one of the suited figures around me was her. Then one of them came towards me and clapped me on the shoulder. ‘I need you to drive forward while I operate the winch,’ said Nadia. ‘Think you can do it?’

I nodded inside my helmet, beads of sweat forming on my head at the thought of what I was going to have to do. I followed her back through to the first vault regardless, and was deeply alarmed to see the lava was now just metres away from the front of our own EV. The heat at such close proximity was astonishing.

Nadia headed for the winch, while I got back inside the vehicle. I didn’t bother taking my helmet off, or cycling through the vehicle’s tiny airlock. There wasn’t the time. Instead I used an emergency override to evacuate all the air from inside in a few seconds, then climbed on board. I’d already been taught how to drive an EV, and I had the engine up and running in seconds.

‘Okay,’ said Nadia over the radio. ‘Pull forward – but don’t take any chances, Jerry. Don’t hang around one second longer than you have to.’

I eased down on the accelerator and rolled the EV forwards as tentatively as I could manage.