Captain Jack Harkness spotted her first; a non-descript woman, early thirties, sitting in the train station's departure lounge. She was staring at a tattered paperback that hung limply in her hand but she wasn't reading. Her distant gaze suggested that she was miles away. There was nothing in particular to indicate that she didn't belong there, after all, half concentrating on a boring novel while waiting for a train wasn't a crime. Not on this planet, anyway.
And the bio-damping field that they were tracking could only be pinpointed as far as the station itself, which covered several hundred square metres and currently held more than 1,000 people. But as he stood in the centre of the lounge, with his team spreading out around him, Jack knew that she was not all that she seemed. That she was the one that Detective Harris was so adamant they capture at any cost.
Harris, the head of the till-recently-missing Torchwood Four facility, was not a man of exaggeration and he had described the alien interloper as the single greatest threat to the 21st Century. And as the woman glanced up and her eyes brushed over him, Jack felt a glimmer of what Harris was so threatened by. A wave of energy pressed ever so gently against his psychic barriers; brushing past him like a stranger in a crowded room.
"Now that's not very human," he muttered to himself just as Gwen appeared at his side.
"I didn't catch that, Jack. Sorry." Gwen was scanning the room with eyes of a trained police officer and Jack was reminded of how fortunate Torchwood was to have her on board. How fortunate for him too.
"I think I found the target." Jack waved at Tosh and Ianto who were on the far side of the station lounge and they slowly headed towards him.
Gwen gasped, "I think we've found more than that."
Time eddied through the station.
Had jack not been so focused on his target, he would have remembered a key point of Harris' brief. This alien, this monster craves carnage, suffering and death on a grand scale. It will suck the life out of every living soul in this city. You will find it wherever people are going to die needlessly.
Of course, Torchwood Three had been closely monitoring the city's hospitals and police stations; every car accident, house fire and mugging had been painstakingly scanned for weeks. It was almost by accident that Tosh had picked up the bio-damping field as she recalibrated the scanners.
And now Gwen had seen the young blonde man, with his neat hair and briefcase at his feet. And she had assessed his tear-stained, sweaty face and the mobile phone that he had clutched to his chest in an instant. In a moment of extraordinarily bad timing, that instant was punctuated by the cry of a small child who stumbled across the carpet. Instinctively Gwen stepped forward; but already it was too late. The young man pressed a button on the phone, closing his eyes in prayer or maybe relief.
In a flash, the alien woman was out of her chair and bolting towards the child. In the second or so that it took for the call to connect, Jack grabbed Gwen's arm, jerking her back and shielding her with his body. The last thing he saw before the explosion was the woman doing the same thing to the child.