Annoyed, Nina looked back at the Nephilim as he asked Zan a question, the translator having to yell a reply before giving his companions a nervous look. ‘What did he say?’

‘He does not like this,’ Zan told her, one hand in a pocket. ‘Nor do I.’

‘Afraid of flying?’

Neither he nor the Nephilim answered. Nina sighed, then sat back to endure the rest of the journey.

After twenty-plus minutes, Colonel Wu peered through a starboard-side porthole in response to a gesture by his daughter. Nina followed his gaze. Xinengyuan was visible, concrete and brick dotted with countless tower cranes spreading across the desert. The helicopter’s course would take it north of the city. She peered through the cockpit entrance, seeing mountains ahead. Not far to go.

Another few minutes, then the aircraft began to descend. Beyond the city was a barren, dusty wilderness. Whatever had prompted the Chinese government to build an enormous new settlement here, it wasn’t the fertile farmland – more likely the combination of a need for jobs and housing for an ever-swelling population, the hope of bringing investment to an isolated region, and somebody aiming to get rich from property sales.

Colonel Wu gave an order to the pilots, then called to Zan, who translated for Gadreel. The Nephilim’s shouted reply was relayed back to the commander. ‘The helicopter is going to circle so he can view the mountains,’ Hui told Nina. ‘When he recognises the landscape, he will tell us where to land.’

‘If he recognises it,’ said Nina. Part of her hoped the fortress would remain lost, her doubts about the Chinese military’s ultimate motives still strong. That led to other worries: if Colonel Wu couldn’t claim his prize, what would happen to her and her family? They had already seen far too much of the secret operation – she couldn’t imagine they would simply be allowed to return home with that knowledge . . .

The helicopter banked into a lazy, sweeping circle. Gadreel looked out at the mountain peaks rising above the distant horizon. If he did recognise anything, he showed no sign. Minutes passed—

The Nephilim suddenly shouted. Zan hastily relayed his words, Colonel Wu barking a command to the pilot.

The helicopter slowed. Gadreel watched the ground slide by. Nina saw nothing but rock and sand and occasional scrubby vegetation, but he was clearly searching for something specific. He looked up at the mountains as if getting his bearings, then back down—

Another urgent call. Colonel Wu issued a new order. The helicopter pitched back into a hover. It hung in the air while the Chinese urgently consulted amongst themselves, then descended. A thump as it touched down, dust swirling outside. The engines powered down.

A thudding roar told Nina the second chopper was landing nearby. She looked out to see what had caught Gadreel’s attention, but found nothing. They were near a low and barren dome-shaped hill, the mountains to the north rising beyond it.