‘You’re saying they built spaceships? Bit of a stretch.’

‘This hasn’t been into space. But we know the Veteres made it to Antarctica. It’s got to be something they built. An outpost, or a ship.’

Vorster caught the end of the muted exchange. ‘It’s not a ship,’ said the former naval warrant officer with professional certainty. ‘Not one you could take across an ocean. It’s got a flat bottom, no prow, no keel. You couldn’t sail that across anything more choppy than a paddling pool.’

‘Do you think we can reach it?’ asked Imka. ‘Arnold and the others . . . they might have taken shelter inside.’

Eddie surveyed the ice wall. The field of inverted icicles stood directly beneath the strange object, and the cliff leading up from them actually went beyond the vertical in places, overhanging the glinting needles. ‘Wouldn’t recommend going that way,’ he said. ‘I could do it, and Marc, you too?’ Naider nodded. ‘But probably not the best idea for the rest of you to climb a vertical line hanging over a load of six-foot spikes.’

Cheng regarded the icicles unhappily. ‘I did tell you I’m not good with heights, didn’t I?’

‘So how do we get up?’ Nina asked.

The Yorkshireman’s gaze swept back across the cliff. ‘There,’ he said, indicating a jutting nose of ice rising from the water not far inside the cave entrance. ‘We can get onto solid ground there, and I’ll climb up to that ledge.’ A ragged rift cut across the wall about sixty feet above until it met a thick, near-vertical pillar of ice standing out several feet from the face. ‘There’s a rope ladder in the gear. I’ll haul it up, unroll it, then everyone else can climb up after me.’

‘What about the rest of the way?’ Imka said dubiously. ‘The cliff’s almost vertical, and there is that big column in the way – how will we get across to the spaceship?’

‘It’s not a spaceship,’ Nina insisted.

Eddie smirked at her before answering the other woman’s question. ‘I’ll set up pitons and ropes so everyone can get around that pillar. Once you get to the other crack,’ he pointed out a weaving line beyond the obstacle that crossed the cliff almost the whole way to the mysterious object, ‘it should be pretty straightforward to sidestep along it. I’ll put in lines you can hold.’

‘You make it sound so easy,’ said Nina. She didn’t doubt that the climb was well within his capabilities, but the constant creaking of stressed ice reminded her that they were in a cave that was slowly but inexorably melting. Surfaces that seemed solid could give way at any moment.

‘Oh, you’ll hear me complaining all the way up. But I think everyone’ll manage it. Even you, Cheng.’ The young man did not look reassured.