‘A few went up and didn’t come back. The man went with them.’ He pointed out the tread of Zan’s shoes.

Eddie nodded. ‘I’d say they sent scouts to check the side tunnel. They came back, told Gadreel what they’d found, and he sent Zan up there. Maybe he even went with him.’

Nina thought back to what she had seen of the shaft. ‘It could be the way to the higher bridge. If it is, then Gadreel’s probably not there any more – he went down that spiral pathway.’

‘So Zan’s alone with the qi tracker?’ said Cheng.

Barney shook his head. ‘A couple of those bigfoot fellas went with him. Even if one’s gone somewhere else, he’s still got company.’

‘Sidona will have the resurrection key,’ said Nina. ‘We need to find her first.’

‘She might have gone with Gadreel and Zan,’ Eddie suggested.

She nodded. ‘And if she did . . . right now she could be alone with Zan! We can get the key and the tracker at the same time. So we need to go that way.’ She indicated the upper tunnel.

Eddie readied the rifle. ‘Let’s do it.’

They proceeded cautiously up the new passage. Like the main route, it appeared to have been carved from a natural fault, but this one was not as wide. Nina guessed the Veteres had not needed to bring sarcophagi through it – which in turn suggested the prison of Tartarus was somewhere below.

Before long they reached another junction – and heard noises. ‘Lights out,’ Eddie growled.

A new passage to their left sloped steeply downwards. A glow was visible at its end – the same multispectral shimmer as the crystal pillar. Signalling for Cheng and Barney to stay put, Nina and Eddie crept down it. ‘Must be something big,’ Nina whispered. ‘It’s lit up like a football stadium!’

They reached the bottom, finding themselves on a balcony overlooking a huge cathedral-like chamber. The pair ducked behind the stone parapet when they saw numerous Nephilim below. Most were warriors, wearing their bizarre, brightly coloured armour, but to the couple’s relief, they did not seem to be expecting battle. They had divided into smaller groups amongst broken boulders scattered across the floor; parts of the ceiling that had fallen over the untold millennia. ‘Looks like they’ve made camp,’ Eddie murmured. ‘I count . . . about eighteen.’

‘And they all squeezed into that little ship?’ said Nina. ‘Damn, and I bet it didn’t even have a bathroom.’

A brief smile, then they surveyed the chamber. A high vaulted ceiling, great vertical columns carved into the red walls. The bases of many had crumbled into rubble over time. Giant heads between them stared sternly down at those below. The stone faces were not human.

Nina recognised the features immediately: the same as those of the mummified corpses she had discovered in the Garden of Eden. ‘The Veteres did build this place . . .’