Another earth energy bolt hit a six-storey office block on the corner. She swerved clear as it collapsed, then held her breath as she sprinted into the swelling dust cloud. Her eyes stung, but the nearby buildings were just discernible enough for her to reach the intersection and round it.

The air cleared. She coughed, powder caking her lips, but kept running. A road sign bore directions in both Mandarin and English. Straight ahead was Commercial Zone No. 4, which told her nothing, but heading left would bring her to something called Fair Rain Residential District. Again, the name was unhelpful – but she saw numerous tower cranes that way, suggesting construction was ongoing. It could be a good place to dispose of the key.

Where was the fortress? She looked over her shoulder – and was shocked to see it descending, slicing through the mushroom cloud rising from the destroyed apartment block towards the park.

It was landing. They were coming after her on foot.

The hunt had become even more dangerous.

Macy clutched at Eddie’s jacket as another building blew apart. ‘Daddy! We’ve got to help Mom!’

‘We will, if I can figure out how!’ he replied. The destruction had been preceded by a weird rippling distortion tearing through the air. ‘Those things under its nose that look like fangs – I think they’re guns. Cheng, you said those spears at the base were weapons, right? They must be bigger versions.’

‘They could be,’ said Cheng. ‘But how does that help us?’

‘They’re underneath it – so they won’t be able to point upwards! If we come in from behind and stay over it, your guys can blow the fu— the flip,’ he corrected, remembering that Macy was in earshot, ‘out of it with the miniguns and those rocket launchers.’ He gestured at the tubular weapons carried by some of the soldiers. ‘Tell the pilot to get above it!’

Cheng quickly relayed the suggestion. It was not met with enthusiasm. ‘He says we have to wait for orders from Major Wu.’

‘Nina could be dead by then! Tell him I’ll lean out and fire at the bloody thing myself if I have to, but we need to shoot it down – or at least keep it occupied until she gets clear.’

Another hurried exchange – this time with more success. ‘He’ll take us in behind it,’ Cheng reported as the pilot banked, bringing the Z-20 on an interception course. One of the gunners slid open a cabin door. Wind blasted in, Macy shrieking and shielding her face. The man hooked himself to a strap, then swung the minigun from its stowed position.