Title: People Killing People.

Rating: Very mild gore and violence.

Summary: New York city is changing. And all Mac Taylor can do in the face of it is keep on fighting.

Disclaimer: It all belongs to not me. I stole the title too.

A/N: Recently completed Prototype on the PS3 and couldn't stop imaging possible CSI scenarios while decimating the city. Thus, a little encounter was born. You don't have to have played Prototype to get it but it helps and you should anyway cause it's awesome. I might add to this if the notion strikes me, but right now it's a oneshot. I apologise for my apparant dislike of more than two sentence paragraphs and the ever present abuse of the comma. Critique very much appreciated.

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It was common knowledge to anyone who knew him that before joining the New York crime lab, Mac Taylor had been in the Marines.

It was a sign of his strength that he had seen so much of the horrors that people could inflict upon one another and yet he still continued to fight against it. He knew how to fight and he was good at it. But he'd never seen anything like what they were dealing with now.

Just over two weeks ago, things had started to change in the city of New York. A sudden mysterious and aggressive military presence could hardly go unnoticed, but that had only been the beginning.

It had been the corpses that warned them something truly terrible was going on.

Mac had realised in the moments standing over the mutilated body of a middle aged woman that he had rarely seen Sid genuinely frightened. Angry, confused, saddened maybe… but as he explained that the teeth that had torn the woman's flesh from her bones had been human, Mac had recognised that fear with a chill of premonition.

Everything since then seemed to him to have followed in an almost incomprehensible blur of shock, of running, of blood and screams and the smell of infection.

It was a smell they'd come to know well. A smell they'd come to associate with terror.

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'Mac, we need to get out of here!'

Stella's shout was almost drowned out by the hoarse screams of the hoard of infected stumbling toward them. Mac grit his teeth, his gaze flickering desperately between the blank walls of the alley and the growling, shuddering mass of bodies.

They were trapped. His grip on his gun intensified and he opened his mouth to tell the rest of them to get back while he tried to thin their numbers, when something unexpected happened.

A good portion of the infected seemed to explode in a shower of blood and body parts and the rest turned their attention to some threat that had appeared behind them, at the entrance to the alleyway. Something that looked organic and alien cut through them, swinging through the air like a deadly whip, crunching into the ground and smashing bodies against the walls with incredible force.

Within seconds the crowd of zombies had been decimated, leaving the exit clear.

Mac held still, his gun pointed steadily at the street, Stella, Danny and Don frozen in the same stance behind him, hating the weight in his gut that told him some new monster had come to hunt them. His blood thrummed through his veins like thunder, his heart shuddered in his chest with the effort of keeping his breathing steady and his sight held firm.

He heard Danny suck in a breath through clenched teeth at the sound of the first footstep and felt the next echoed in the twitch of Stella's body behind him. The figure didn't so much emerge from the shadows as seem to coalesce from amongst them and after a second of staring intently, Mac realised it was a man.

He didn't relax his stance. The city had taught him not to trust his eyes.

The man was tall and imposing in a black leather jacket with a grey hood pulled over his head, but it wasn't his clothing that made Mac wary. There was something in the way he stood with his head slightly bowed and his shoulders strangely stiff, arms hanging loose at his sides – it was a ready, sturdy bearing but it was unafraid. His head tilted slightly as he moved, as though he were constantly listening, constantly aware.

This man had nothing to fear here.

In a flicker of movement that was both sudden and slow, Mac found himself meeting cold blue eyes staring out from a shadowed face that had all the appearance of humanity and yet lacked any semblance of it at all. He took a deliberate step toward them and panic coiled in Mac's gut with alarming intensity at the instinctive realisation that they were facing the most deadly predator on the streets of New York.

He didn't realise he had taken an automatic step back until the echo of his companions footsteps told him they'd done the same. For a second he swore he saw a cold smirk slide over the man's face before his head jerked to the side as though reacting to a sudden noise. Sure enough, a mere second later, a terrible roar echoed along the buildings and shuddered down Mac's spine – he recognised it as the call of one of those mutants that came from the hives.

The man responded strongly to the sound, burning rage flickering over his face and his muscles tensing in a display of emotion that took Mac by surprise. The coldness he'd perceived in this creature before them was washed away as something smouldering and powerful took its place.

He paused to turn his gaze on them again, considering, and Mac thought of mist and black ice and nightmares, and almost prayed.

Then his head tilted downward once more and in a flash of movement he was gone.

Without thinking, Mac moved quickly out into the street, the others following and they watched as the figure of the man sprinted down the street, vaulting the wrecks of cabs and piles of bodies with ridiculous ease. His movements were smooth and sure and when he flipped over a heap of rubble and continued to sprint along the side of a building, swerving and spinning over ledges and fire escapes, it seemed completely natural.

They watched until he was out of sight and then there was silence.

Mac let his breath out in a rush and closed his eyes against the reality he found himself in, the constant wash of shock and fear pulsing heavily behind his eyelids. He furrowed his brow against the sensation and only opened them when a snort and a muffled curse pulled his gaze to Don.

The bags under his eyes and smears of blood and dirt across his face somehow couldn't totally diminish the familiar sardonic tilt to the Detectives eyes as he rolled his shoulders and huffed.

'I dunno why I bother being surprised anymore.'

Then he checked his gun and turned to walk back toward the safe house.

The rest of them shared a rare smile and followed.

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