How long it would remain there was another matter. Icy flakes constantly fell from around it, the low moans of the overstressed ceiling louder and more alarming now he was closer.

The thought spurred Eddie to quicken his pace. He moved on, laying a trail for the others to follow, until he reached a jutting ledge just beneath the ‘spaceship’. The inverted icicles stabbed up at him from below.

The view above was no less unsettling. He was almost underneath the looming metal shape, and something made a sixth sense clamour in warning. He couldn’t escape the feeling that even after being buried for over a hundred thousand years, the object was not inert.

He put the disturbing thought aside and shouted back to the rest of the party. ‘Okay, ropes are in place! Come across!’

Nina led the way, picking her way around the icy outcrop to the crack. With the line to support her, it did not take long to reach the frozen ratchet. ‘Oh, this is conveniently placed!’

Eddie started drilling screws to act as steps up to the higher ledge leading to the opening. ‘Hold the spike I put in as you go around, you’ll be fine. Just make sure you’re still clipped to the rope.’

‘I wasn’t planning to unfasten myself, don’t worry.’ She looked down. The drop to the frigid water below was an almost sheer sixty feet. ‘Actually, I might put another clip on!’

Eddie smiled, then resumed his task.

She took hold of the protruding ice screw and leaned back as far as she could, pushing out her butt to clear the metal talon. ‘This is dignified. I’m glad nobody’s filming me!’ The ice under her crampons crackled, but held. She brought herself around the ratchet and, relieved, continued onwards.

She soon reached the wider ledge. Her husband was above, finishing the steps to the object. This close, she finally got a full sense of its dimensions. Her first thought was that it was the size of a plane, a small commuter jet or large business aircraft, but that was doing it a disservice. An airplane’s fuselage was a long, slim tube, but this was wide as well. Vorster was right that it couldn’t be a ship; the underside was practically flat. A giant sled, able to be towed across the ice? It didn’t seem likely.

So what the hell were they dealing with?

Eddie started to descend. ‘Ay up. Here comes Cheng.’ Cheng clumsily clambered around the outcrop. His movements were made more awkward by his backpack. ‘What’s he got in there? Bowling balls?’

‘I think it’s his laptop and satellite link,’ said Nina.

He scoffed. ‘What’s he going to do, livestream everything?’