This is my first Threshold fic, hope you enjoy.

Part one

'What have you got?' Cavennaugh spoke quietly as they swept through the warehouse. They had already turned up a number of dead and grossly distorted bodies and were aware that several people had made their escape the moment they had entered the building. A few had been stunned and contained and were being transported securely to Threshold HQ for further tests and questioning.

'There's someone else alive here, sir,' Robinson advised him from the opposite side of the building. 'They're coming this way.'

'Keep your eyes open, gentlemen,' Cavennaugh gave the order as the net began closing in. 'We don't want to let another live one get away.'

No-one spoke as the search parties on both sides of the warehouse drew the net tighter until there was only one possible place for the fugitive to be: at the end of a dimly lit row of shelving units.

Signalling Robinson and Jameson to move to the other end of the units, Cavennaugh positioned himself at his end, shining a torch to provide some illumination and was rewarded with the sight of a figure trying to make itself as small as possible.

'FBI, come out with your hands behind your head,' Cavennaugh called out, his gun trained on the figure, following its every movement. Instead of obeying, the figure stood up, revealing itself to be a woman holding a gun.

'No!' The woman yelled at him, the hand holding the gun shaking. As Cavennaugh made his way towards her holding his own gun steady she began to back away, completely unaware of the two men coming up behind her. A hand closed over the gun in her own hand and she whirled around, lashing out and breaking free though leaving the weapon behind. In that instant of distraction, Cavennaugh grabbed her, snapping the handcuffs on her wrists.

'You can either walk or we can pick you up and carry you,' Cavennaugh advised her. 'I would advise you to co-operate though, everything will be much pleasanter if you do.'

'How do I know you're not one of them,' she snapped as she struggled to free herself from his grip.

'I already told you we were FBI.' One of the Agents flashed his ID so she could see it.

'How do I know that? They all seemed normal when I first saw them. You might change, just like they did.'

Before Cavennaugh could respond, a terrified look came over her face as she saw something behind him. He whirled around, trying to see what had scared her so badly but could see nothing. As he turned back in confusion, a blur caught the corner of his vision and he fired several shots before the figure had chance to reach them.

'How did you know?' Cavennaugh asked.

'I don't know, I just knew he was there. It was the same with the others, I knew they were coming and was able to hide from them. It didn't always work though, sometimes there were too many of them and I had to shoot them before I could get away. They didn't die, but it gave me time.'

'I see.' Cavennaugh didn't understand but knew that this could be one of the missing links they had been searching for. 'You're going to have to come with us.'

'Why?'

'It's a matter of national security,' Cavennaugh told her bluntly. 'I'm afraid you don't really have much choice.'

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'What's going on?' Molly asked Cavennaugh as Fenway began checking the new arrival in the back of the transport vehicle.

'This is the last one – Linda Reeves according to her ID,' Cavennaugh reported, his eyes never leaving the scene in front of him. 'She passed out just before we arrived. I thought she was faking at first, but she was feverish and having difficulty breathing.'

'And you said she was acting differently from the others?'

'Yes. She seems to have some knowledge of what other infectees are about to do. Her reactions when we arrived were unusual as well - she was trying to defend herself, not attack.'

'This could be the breakthrough we've been looking for,' Molly looked thoughtful, turning to Fenway as he finished his initial exam.

'It looks like 'flu,' Fenway stepped back while Linda was secured on a stretcher. 'But there are some other symptoms that I need to check out.'

'Is she infected?' Molly asked.

'She does have low levels of alien DNA in her blood. I'll need to carry out further tests to determine the extent of the infection.'

'We'll need to talk to her as soon as possible – Cavennaugh says she can predict the actions of others who have been infected.'

'Interesting. I'll look into it, and I'll let you know when you can talk to her.'

As soon as the medical team had cleared the area, Molly pulled Cavennaugh to one side.

'What about the other survivors?'

'They should all be in the holding cells right now.'

'Good. And make sure there's extra security with Linda, we can't afford to take any risks.'

'Already on it.'

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'How's she doing?' JT had joined Molly in the med lab where Linda had been taken.

'Her blood has trace elements of the alien DNA and she's showing an increase in theta wave activity which means she was exposed to the signal. It's too early to determine whether she's going to turn into a full-blown infectee,' Fenway reported. 'She does have 'flu but there's also secondary encephalitis. It's not too serious but it's going to be a few days before she starts to improve.'

'I don't suppose it's any use in suggesting she be moved to one of the detention cells?' JT was pretty sure what the answer would be even before Fenway responded.

'No it's not. She needs to stay in the med lab where she can be monitored. Complications can develop very quickly with encephalitis and if we don't catch them early enough, she could suffer from brain damage or die.'

'I know we've been through this before,' JT sounded exasperated. 'But I really think she should be secured now before something can go wrong.'

'Then you should also remember that I don't back down easily,' Fenway snapped back. 'She doesn't pose any immediate danger and unless you want to question a corpse, I suggest you leave her where she is.'

'I'll let it go for the moment, but you'd better make damn sure nothing happens.'

'Linda, my name's Molly Caffrey,' Molly approached the patient who was secured on one of the beds. 'This is JT. We need to ask you a few questions.' Linda looked warily at the two of them, but nodded her agreement.

'Can you tell us what happened before you got to the warehouse?' JT asked.

Linda remained silent for a few moments before responding. 'I'd gone to the pharmacy to get some 'flu medication. There was a crowd of people around the instore TV, it was playing some kind of infomercial. I went to see what was going on but it was just a weird symbol on the screen. I couldn't see what all the fuss was about so I just paid for what I'd got and left.'

'What did the symbol look like?'

'It had three legs, all bent around into a circle.'

'Was there any sound?'

'I heard a buzzing, but then my ears were blocked and I couldn't hear anything properly – I thought it was because of the 'flu.'

'Ok, then what happened?'

'I was on my way home, waiting for the bus, when I felt like I was being followed. I got really nervous and started to walk, to get away from whoever it was, but the feeling stayed with me until I reached the warehouse. I went in, I don't know why, and…they kept coming for me, it was like they knew where I was. Every time I thought I'd lost them, another one would find me. I got a gun off one of them and managed to keep them away and then the FBI turned up.'

'That'll have to do for now,' Fenway interrupted. 'She needs to rest.'

'Hey,' Linda called JT and Molly back as they turned to leave. 'Aren't you going to tell me where I am and what's going on? And I need to contact my family, let them know where I am.'

JT turned back. 'I'm afraid we can't tell you anything right now, it's a matter of national security. We've already contacted your family to let them know you're safe and will be in touch soon.'

'Who the hell do you think you are to go around dictating to people like this? I've got rights, you know, I want to know…' Linda broke off as she found it getting harder to breathe and began to panic.

'I said you should try to remain calm otherwise it would aggravate your symptoms,' Fenway told her bluntly. 'Now, take some slow, deep breaths and I'll give you something to calm you down.'

A few minutes later she was drowsing under the influence of the sedative she had been given.

'You know, she's got a point,' Fenway snapped at JT and Molly as he caught up with them in the control room. 'You can't just spirit people away and tell them nothing.'

'We'll deal with that later,' JT told him coldly. 'Would her ears being blocked be enough to stop her getting the full effect of the signal?'

'Possibly. The clerk's deaf and she wasn't affected at all, but it may simply be too early too tell. I'll do regular blood tests but beyond that, we'll just have to wait and see.'