‘Never thought what?’ Nina prompted after a silence.

‘That – that I would find something like this. An outpost of a lost civilisation, a lost race, hidden in the ice for all this time.’

‘You think it’s an outpost? Some kind of building rather than a ship?’

‘I don’t believe it’s a UFO,’ he said, directing a small smile at Eddie’s back. ‘And Mr Vorster is right. It’s the wrong shape to travel on the sea. It must have been built in Antarctica.’ He looked up at the dark, sinister shape. ‘A fortress?’

‘Protecting against what?’ Nina asked, though she had her suspicions. The Veteres had travelled to the literal ends of the earth to escape their former slaves: humans.

Although that description wasn’t strictly true, she reminded herself. The Veteres certainly considered humans as lesser beings, much as humans regarded apes and monkeys, but they had tried to teach and uplift them to something more. Their mistake was in not recognising until too late that distinctly human trait: applying any new knowledge first and foremost to the purposes of violence. They had given their primitive charges the most powerful weapon possible to use against them.

Imka arrived. Vorster began his traversal, Naider rounding the icy outcropping behind him. ‘It’s gonna get cramped on here,’ Nina said to Eddie. ‘Some of us should go up to make room.’

‘“Some of us” meaning “the redhead New Yorker”, right?’ Eddie replied.

She grinned. ‘Am I that transparent?’

‘You’re easier to see through than this ice. Go on up, then. We’ll follow as soon as Marc gets across. Oh, and radio the Torrox – let them know we’re okay and that we’re checking the ship.’

Nina glanced between the inverted Dionysius and its shadowy companion. ‘I guess we don’t need to tell them which ship just yet, huh?’ She took Eddie’s radio, then moved to the ladder of ice screws. ‘Cheng, with me.’

She started up the cliff face. Eddie had drilled in enough steel rods to make the ascent straightforward, but a glance at the icy stalagmites far below gave her added incentive not to get complacent. Before long she reached the upper ledge and clambered towards the unidentified object.

The tall oval opening loomed across a short expanse of exposed metal. She switched on a flashlight and shone it inside. A door made of the same faintly oily-looking material was revealed, a disc inset at its centre. Beyond was a passageway, tilted at the same steep angle as the rest of the object. Exploring the interior would be tricky; they might need ropes to stop themselves from sliding out of control.

She radioed Tate to update him on the situation. ‘Roger that,’ the Australian replied, crackling interference masking his voice. ‘Any sign of the Dionysius’s crew?’

‘Not yet,’ she replied. ‘We’re going to start a search.’

‘Understood. Keep us posted.’