The young Chinese was too absorbed to recognise the mockery. ‘I don’t need it, the files are on the hard drive.’ He sat, balancing the machine on his thighs as he worked. ‘Yes! I was right. They are words.’

Nina looked up at the indistinct shapes. ‘What do they say?’

‘They’re a warning. I can’t read the whole thing, but my guess would be “Stay away, there are Nephilim inside.”’

Macy gave her mother a smug smile. ‘See? I was right.’

‘Yeah, that’s enough of that,’ Nina sighed. ‘Okay, this is the place. So where are the Nephilim?’

‘Who?’ asked Barney.

Eddie beat her to an explanation. ‘Ancient race of bad guys. They were frozen, they woke up, they’re not happy – and they think their mates are inside the rock.’

‘Frozen?’ The idea appeared to trigger some memory for the ranger.

‘If the warning is here, the entrance must be here as well,’ Cheng suggested.

‘Good point,’ said Nina. ‘If we can find their tracks, we’ll be able to see where they went.’

Finding the footprints of over twenty giants, even after several hours, was not difficult. The oversized tracks led to a small cave almost directly beneath the giant skull. ‘Okay, they went in,’ said Eddie, ‘but they didn’t come back out.’

Nina checked the cave. It did not take long; it was barely ten feet deep. ‘Secret entrance, maybe?’

Barney made a sarcastic sound. ‘We’ve lived here for thousands of years. We know every centimetre of the rock. But I suppose another great white explorer’s going to find something we missed?’

‘This isn’t the time for that, Barney,’ chided Sandra.

He grudgingly acknowledged her words, but still muttered, ‘She’ll probably name it after herself.’

‘Cultural imperialism bad, that’s Archaeology 101 – at least in my classes,’ said Nina, taking a closer look at the cave walls. ‘But right now, all I care about is stopping the Nephilim. They came in here, and since they can’t walk through solid rock, there must be another exit.’ She put her palms flat on the stone in the hope of feeling some connection to whatever had brought Gadreel’s people here, but there was nothing.

Then where had they gone? The cave was shallow enough that sunlight reached the back wall, exposing every detail. There was nothing that could be an opening, a keyhole . . .

Some instinct made her look up. The ceiling was naturally in shadow, and at first glance it seemed to be made of the same vivid sandstone. But a crack ran to join a larger one angling all the way down the edge of the rear wall. She gazed at it. There appeared to be a piece of darker stone in the crack above. ‘Eddie, can you pick me up?’

‘You’re a beautiful, intelligent woman,’ he replied.

‘What? Ohh,’ she groaned, getting the joke. ‘No, I meant literally. I need a closer look at the ceiling.’