‘Of course. I gave them our GPS coordinates, so they should—’ A new bubble of text popped up. Cheng read it, then looked around with a smile. ‘Yes! They’ve contacted another ship, which is diverting to find us.’

‘How far away are they?’ Nina asked.

‘I don’t know,’ was the almost apologetic reply, before an idea came to him. ‘But I can track them! Wait, please . . .’ He turned back to the screen, bringing up an internet browser and performing a search. Most of the text on the page that came up was Mandarin, but a logo read TrackShip.

‘The rescue ship is called Destiny Sunset,’ said Cheng, typing it in. A pause, then a picture of a large bulk freighter appeared. He clicked a button beneath it. A world map loaded, zooming in on the southern hemisphere. ‘It’s here, heading for Melbourne, and we are . . .’ He scrolled south-east to empty ocean, checking coordinates. ‘Here.’ He flicked between applications to make calculations. ‘Oh. Over seven hours away,’ was his unhappy announcement.

‘We’ll survive,’ said Eddie. ‘But we need to get out of this wind before we freeze. Pack up your computer, and— No, hold on!’ He stopped Cheng from closing the screen. ‘I saw Harhund’s ship. Tahatu, I think it was called. Put the name in, see if you can find it.’

Cheng did so. The ship tracking website produced a new image, a much smaller black-hulled vessel. ‘That’s it,’ said Eddie. ‘What does it say about it?’

The Chinese read the text. ‘Not much. It’s privately owned, registered in New Zealand.’

‘Can you track it?’ asked Nina.

He clicked the appropriate button. The map reappeared, again showing an empty patch of the Southern Ocean. ‘Not far from us.’

‘On the other side of the iceberg, thank God,’ said Imka.

‘I can track its recent movements. Wait, please . . . Yes. It came from Auckland. It sailed four days ago.’ The ship had come around the tip of New Zealand’s North Island before angling south-west.

‘That’s before we left Australia,’ said Nina, puzzled. ‘They had to go farther, so they arrived after we did – but they knew where we were going!’

‘How?’ Eddie said in disbelief. ‘We didn’t tell anybody.’

‘Nor did I,’ Imka added.

Cheng looked up from the laptop. ‘The only person I’ve spoken to is my mother, and I don’t think she would send international mercenaries to kill me.’

‘Depends; when did you last clean your room?’ Nina said with a half-smile.

‘Someone knows way too much,’ Eddie rumbled. ‘They knew how to find us, and what we were going to find inside the spaceship.’

‘It wasn’t a— Oh, you know what, forget it. But you’re right, they knew a lot more than we did. Including,’ she said, feeling a chill unrelated to the cold, ‘that they’d need me to make the earth energy technology work.’