Even with the defenders, Macy still heard her mother’s name. ‘What’s happened to Mom?’

‘As far as I know, she’s still inside the fortress,’ Cheng told them. ‘So is Zan.’

‘How long before we get there?’ Eddie demanded.

‘A few minutes—’ He paused, listening to his earphones. ‘The pilot can see the fortress!’ he reported. ‘It’s heading into the city. Major Wu has ordered the other helicopter to pick her up.’

‘What about this one?’

‘We’ve been told to observe the fortress from a safe distance.’

‘How far is safe?’

Cheng grimaced. ‘They, ah, don’t know.’

‘Great, so if its guns have a range of fifty miles, we’re buggered!’ Eddie held on to his daughter as the Z-20 banked towards the fortress.

Nina rushed out of the apartment block. The city centre had been to the south; she found the sun and got a rough bearing. No sign of the fortress – yet. She needed to get away from her landing site before it returned.

She ran across the park, ducking under trees for concealment. Down a flight of steps, through a gate and onto a street. A mixture of residential buildings and shops greeted her; the latter were all empty, some so newly built that tape crosses still adorned the windows. There were no people, no cars.

Shaking off the sensation that she had arrived late to the end of the world, she ran on. Tall cranes were visible to the west, one lazily turning. She headed for them: a construction site was still her best hope for rendering the key irretrievable.

The first proof that she was not alone came when she heard tyres screech about a block away. Considering the lack of traffic, it was less likely to be a near miss than someone seeing the huge flying dragon and skidding in disbelief. She hurried across the empty street to get under a long awning, then looked back—

A huge shadow swept over the apartment complex.

The sight, straight from an alien invasion movie, momentarily froze her. The fortress hove into view, its silence as unsettling as its size. It slowed, the fangs moving to point downwards—

The building with the swimming pool blew apart.

Nina screamed and ran as the pristine block disintegrated in a storm of shattered concrete, a seething grey dust cloud erupting like volcanic ash. Windows in neighbouring buildings shattered as hundreds of tons of rubble slammed to the ground.

‘Oh my God . . .’ she gasped, hoping the block had been as empty as the rest of the neighbourhood. Clutching the key, she kept running, trying to keep out of sight.