To those normal, mortal beings around her, she moved as a fluid blur of violent action, suddenly airborne, one long leg pistoning out and into the sternum of the armed attacker. The gun fired again, bringing down a shower of plaster dust from the ceiling as he slammed backwards into a wall. His head struck a metal oxygen tap with a wet crunch and he began a slow drop to the ground, trailing a greasy organic smear down the wall.

Without pause, Caitlin’s whole body swept around in a small, self-contained tornado, one foot lashing out to strike squarely at the gun hand of her second foe, who had just jacked in a fresh mag as she struck. The pistol, a Glock 23, discharged a single round, shattering an overhead fluorescent light. Turning tightly with the direction of the kick, getting right inside the circle of her man, Caitlin shot out her free hand, grabbing his wrist, extending it up and slamming her other arm in under the elbow to snap the vulnerable joint with a terrible crack. In a flash, her weapon hand whipped backwards and she opened up his throat with the razor-sharp scalpel. A geyser of hot blood spilled out in a rush as she continued to spin, dragging the bulk of her victim around between her and the first man. Only then did she strip the Glock from the weak, rubbery grip of the man who was already slumping out of her grasp. She felt fingers breaking as she wrenched it away.

In the space of less than three seconds she stood over her would-be killers. The pistol was already cocked. Two loud, flat cracks rang out and she finished off the prone figure by the wall. A slight shift in stance as she swung around, and she double-tapped the man at her feet, even though his life was already bleeding out of him. Almost no thought went into the actions. She hadn’t indulged herself in the luxury of conscious thought since the two of them had burst into the ER. She simply reacted, her mind and body running along tracks that had been laid down for her by thousands of hours of training.

‘Non!’ screamed a voice. Monique’s. ‘What are you? You fucking monster!’

I’m Echelon, thought Caitlin as she took the weapon from the lifeless hand of the first man she had killed. The ER was unnaturally still all around her. Nobody had yet recovered from the shock of such extreme and unexpected violence. Her gun hand seemed to float towards the weeping French girl. A slow, inhuman movement, machine-like in its lack of compassion. Monique was no longer an asset, a resource to be exploited for the mission. She was a loose end.

7

GUANTANAMO BAY NAVAL BASE, CUBA

The Cuban officer’s salute was crisp, and his posture ramrod straight, but his eyes betrayed only confusion and anxiety. Musso returned the salute before dropping into a more relaxed posture. The two men stood in a bare office, borrowed for the meeting. Until two days ago it had been the domain of a navy lieutenant, but he had transferred back home and nobody had yet arrived to fill his berth. And five’ll get you fifty that nobody ever would, Musso thought bleakly.

‘Major,’ he said, to open the discussion, ‘welcome to Guantanamo Naval Base.’

Major Eladio Nuсez bobbed his head up and down in an agitated fashion.

‘Would you care to sit?’ asked Musso.

‘Si. Thank you.’

Nuсez dropped into a chair with some relief. His aide, a captain, remained at attention by the door. Lieutenant Colonel Stavros stood at ease by the cheap government-issue desk on which Musso had leaned back. Outside, the base was locked down on its highest alert. Two Marines in full battle gear doubled-timed past. They were ready. The question was simple enough: ready for what?

‘This… ah… this is very difficult, you understand,’ said Nuсez. He leaned forward, his hands rubbing together nervously. ‘We do not… I don’t…’

‘You’ve lost contact with Havana,’ Musso offered.

‘Si. But more than that. Something strange. A few miles to the north of my position – a sort of heat curtain. We can see the land behind it, through a haze, and it looks normal. But nothing, or no people, move there. There is a town, not far beyond the line, on the road north. Nothing. Not a soul.’

Musso nodded. Nuсez was deeply agitated but Musso was not so stupid as to make any judgments about the man’s character on that basis. The major had been chosen by the Cuban military to face off a mortal enemy, squatting on the very soil of his motherland. He would be neither a fool nor a coward.

‘Have you sent anybody in?’ he asked. ‘To investigate.’

The captain standing by the door moved fractionally. A tic flickered under one eye.

Nuсez nodded. ‘Yes. I send in some scouts. They appear to, uh, to disappear in the heat haze. It was very thick, very powerful, no, near the effect? It seemed much hotter. And so my men they walk in, slowly. They…’ He groped for the right word. ‘They shimmer, yes? In the haze. And they are gone.’

‘Just gone?’ asked Stavros.

Nuсez nodded vigorously. ‘Yes. Sometimes the haze seems to shift, like a curtain, just for a second, and we can see further down the road, say two hundred metres. It is like looking into a fish tank, yes, in a restaurant? It is a very strange sight. Like a curtain of air? I do not see how that can be but it… ah…’ He rolled his hands in a helpless gesture, again seeking the right words. ‘You can see this curtain. But the scouts, they never emerge on the far side. Their uniforms, they fall in a heap. Charred and smoking.’

Musso frowned. He thought he understood what Nuсez was describing. The heat wall sounded a little like a blast wave – the front of super-compressed air that moves outwards from the point of an explosion. But in this case it wasn’t moving, or compressed. It merely hung in the air like a ‘curtain’, as Nuсez had called it.

Musso cleared his throat. ‘Major, my own observers reported some of your men heading north…’

‘Si,’ he said bitterly. ‘They abandoned their posts.’

‘And they ran into the haze?’

Nuсez nodded, looking almost satisfied. ‘Yes. There was no need to shoot them. They have gone too.’

‘I see,’ replied Musso. ‘And so what would you like us to do?’

The Cuban shifted uncomfortably in his seat, looking around, surprised at last to find himself in the devil’s lair. He sighed. ‘We would like help. We are not a tin-pot dictator’s ship,’ he said, forcing Musso to suppress a grin for the first time that morning. ‘We nave been intercepting your satellite news services. We know this is beyond the normal. Something terrible and large is happening. We need to know what. To prepare.’

Musso folded his arms and let his chin rest on his chest.

‘This “curtain” of air,’ he said after a brief moment of quiet, ‘is it stable? Is it moving, expanding, at all?’