‘Saves on food and water an’ all, I suppose.’ Eddie glanced back at Cheng. ‘You okay?’

‘Yes,’ Cheng replied, though he was breathing heavily with exertion. They had come quite some distance down the winding tunnel. ‘At least it’s cooler than outside.’

As Nina gave him a reassuring look, Barney caught her attention. The Anangu appeared nervous, understandable as the group descended into the unknown – but there was also something pensive about his expression. ‘What is it?’ she asked.

‘You say these . . . beings were asleep for a long time, frozen, and then were woken up?’ he said. She nodded. ‘We have legends about things like that. Like the Ninya, the ice men – they’re asleep under a lake a few days’ walk from here.’

‘The legends could be based on reality,’ said Nina. ‘I know there’s an Australian tribe with a legend of a fire demon that fell to earth, and scientists found evidence of a four-thousand-year-old meteorite impact in their territory.’

‘The Luritja,’ he confirmed. ‘But I always knew all our stories were true, if you understand the way they’re told. I didn’t expect this, though.’ He gestured down the tunnel.

‘If it makes any difference, nor did I.’ She gave him a small smile, which to her surprise was returned.

Eddie held up a hand. ‘Everyone stop,’ he warned quietly. ‘Turn your lights out.’

‘We won’t be able to see anything,’ Cheng said.

‘And nothing’ll be able to see us,’ replied Nina. She switched off her flashlight, Barney doing the same.

Darkness swallowed them. They stood statue still, listening. Faint echoes reached them: dripping water. ‘I can see something,’ she whispered. A faint greenish light became discernible down the tunnel.

‘Is it them?’ said Cheng.

‘Dunno,’ Eddie replied. One hand against the wall for guidance, he slowly picked his way onwards. The dim glow revealed a sharp bend in the passage ahead. Whatever the light’s source, it was constant, unmoving. ‘It’s not firelight, and it’s not like earth energy. It’s . . .’

Unexpectedly, he laughed.

‘What?’ Nina demanded. ‘What is it?’

‘Come down and see. Turn your light back on until we get to the turn.’

She switched on the flashlight, and they made their way to the corner. ‘Okay, now switch off,’ said Eddie. ‘Close your eyes first, it’ll help ’em adapt.’

‘Are you sure it’s safe?’ asked Cheng.

‘I don’t think it’s the Nephilim. But you’ll see in a second.’

Nina gave the Chinese a shrug, then shut her eyes and switched off her light. Barney followed suit. She waited for several seconds, then looked again. The glow was now sufficiently bright to let her see the shadowy forms of her companions.

‘Okay, come through here,’ said Eddie, advancing cautiously. ‘Careful, there’s a drop.’