<_What were you thinking?!

Karr cringed away from his brother. The other AI was omnipresent in Karr's CPU, threads of him pervading the darker AI's program, knitting code as fast as he possibly could.

<_I-

A solid wave of fear and anger swept over the virtual landscape. "You risked Nick! You risked yourself! You-" Karr shivered as the parasitic program bit in deeper. Kitt grabbed at it, fighting it. A stream of binary code equal to an electronic expletive danced across Karr's vision. "You risked us all. All because you don't trust-" Kitt flinched as the creature snapped at him, the sickly green staining the younger AI's brilliance. Karr snarled and using what little energy he had, swiped at it.

Kitt lost his grip and the program returned to nibbling on Karr's code, corrupting lines essential to his core functioning. The AI groaned.

<_No! Kitt flung himself at it again, the bright white sharpening to a slither of knife, stabbing the parasite, cleaving its code in return. It faltered and began to rewrite.

Karr reeled, his brother's anger and fear swamping his own. Nick wasn't there. The AI had walled him off, terrified the parasite would attack his driver again.

He had thought he had it under control. It was only a little thing, a remnant that had attached itself unnoticed. It was not viral. He hadn't been concerned.

But then it had proved to be less simple than it seemed. Something new. Something parasitic. It fed off him and the longer it was attached, the stronger it became. It found an opening in his damaged programming and like a leech had nestled itself into the wound. Karr didn't realise what was happening until it was too late.

Until it reached out for Nick.

He had blocked himself off from his partner, determined to fix the problem himself, but unbeknownst to him, the program had burrowed access through his shields. A panicked yelp from his driver and he had spun to find the ice blue spark that represented Nick struggling with the same sickly green that stained his own visage.

Karr didn't hesitate. Flinging himself down the link, he tore the creature from his partner, throwing it across virtual space. It snarled at him and leapt, splicing functions and carving code. Karr cried out and fell back, stumbling out of Nick's mind, dragging it with him, throwing up blocks as fast as possible.

And he'd cornered it in his own CPU.

He fought it with everything he had, but he didn't have enough. It wanted Nick. It wanted Karr. It ate. It destroyed. And he didn't have the strength to defeat it.

He needed help.

He needed Kitt.

So throwing up as much protection as possible, he had snaked a portion of himself into the link between the two AIs.

Knight's sudden fear for him had been palpable.

Kitt spun away from his partner. //<_Karr!//

And Karr found himself slipping, falling, back into his CPU, weakened by the creature sucking at his strength.

Kitt had charged in and the struggle had begun.

<_I can't believe you did this!

Karr's temper flared. <_I do what I must.

Weaving code, Kitt was writing at a speed Karr hadn't thought possible, each segment slotting into place, protecting, bandaging, and defending. Simultaneously, his brother was building another program, its ethereal structure forming in a far corner of Karr's CPU.

Both AIs watched the parasite, holding it off long enough to regain strength even as it did the same.

<_What you did was stupid, Karr.

<_I have the right-

<_No, Karr! Stupid! You don't have to protect me! We're in this together. We've been in it together for years! When are you going to learn???! The AI was so very angry, Karr found himself flinching away from his brother's presence despite himself.

<_I thought I could handle it.

<_Really? Is this what you call handling it? It hurt Nick, didn't it? And I can't help him now because I can't leave you! Another wave of fear. <_And Michael...if he attempts anything...

Kitt was here giving everything he had to save his brother while Nick could be lying unconscious somewhere. Karr struggled against the grip Kitt had on him.

Kitt flickered a moment, his anger faltering as if he realised what he had said. <_I'm sorry. Sit still. I'll be as quick as possible.

There was silence between the two AIs for a moment. Kitt continued to write repair code and the structure he was creating took on a more solid shape. Karr flicked a glance at it, curious despite himself. He'd never quite seen a program like it. "What is that?"

Kitt's virtual gaze paused a moment as he looped several functions and activated a sub-program to stonewall the parasite should it attempt to attack the new code. "It is necessary."

His brother was tight lipped and angry.

Karr shut up. Everything he was, everything that gave him strength, fought against exposing his vulnerability. He hated this, but there was something about watching his brother work, seeing the skill exhibited as the AI manipulated code that showed him something he had never seen in Kitt before.

Karr knew his own skill in virtual reality, he knew he had what it took in most cases to hack into any system. He had fought a variety of wardens, sentinels, security measures, even the occasional virus, but what Kitt was doing...it was more than first aid. The AI was blending code of his own construction to replace the damaged strings of Karr's own. There were faint streaks of white mixing with his inherent darkness, the green struck from him and replaced with his brother.

Kitt was creating.

And that was the core of their difference. Karr destroyed. Kitt created. He attempted to shrink back again, but Kitt sent another wave of anger in his direction and pinned him with a stab of white light. <_At least hold still.

<_Sorry.

Again there was silence.

Finishing off the secondary structure, which now clearly resembled a cage, Kitt paused a moment in his aid to Karr, and turned to the parasite. His brother ejected a spear of code directly at the creature. It responded, stimulated from its rewriting and repair activity, it spun and moved to attack the taunting AI. Karr leapt up, moving in to protect his brother, but was suddenly thrust back by the AI. <_Wait.

A similar stream of code suddenly erupted from within the cage structure and the parasite turned, attracted to this new source. The signal was strong enough to lure it from Karr completely and it followed the code into the cage. Kitt flicked off a function and the cage door dropped, capturing the program behind an elaborate lattice of firewalls and traps. Another signal and the structure collapsed in on itself, crushing the program inside, shredding its code into binary nonsense. His brother borrowed one of Karr's janitor programs and the mess was swept away into recycling.

Turning back to the injured AI, Kitt began weaving the final work of code to stabilise him. Karr just stared. <_How?

<_I've encountered it before.

Karr waited, but his brother didn't say anymore. <_Where?

Finishing off the last section of code, Kitt stepped back, his visage rippling with control. <_Berio.

-o-o-o-

Kitt 'woke' in Michael's arms. His driver was clutching at him, rocking him gently. He hadn't meant to leave so obviously, but Karr had needed everything he had. //Love?//

//Kitt?// The rocking stopped. //You okay?//

//I am. However, Karr is injured and I must see to Nick.//

There was a wave of frustration from his driver as he realised there wasn't a single thing he was capable of doing to assist. The AI reached up and kissed him softly on the lips. //Rest, love. I'll take this one.//

Kitt scrambled out of bed, throwing on his shirt as he headed out the door. Skipping down the stairs as if they hardly existed, his glance skittering over the Stealth, he found Nick collapsed in front of his laptop. Fortunately the couch had caught him and he was just lying awkwardly on the upholstery rather than broken on the hard ground.

"Nick?"

No response.

Reaching him, Kitt checked him over. He appeared to be unconscious. Medscan revealed little more than a small amount of swelling around the implant in his head.

<_Karr?

His brother was trembling and limping. <_He is unconscious. I can't detect any permanent damage.

Making Nick comfortable on the couch, Kitt put the agent's laptop on standby and sat down next to him. //He's okay, love.//

Michael reached out and wrapped his amber essence around the AI. Karr, sensing Michael's presence, backed off, but Kitt snagged him before he could throw up the first block. <_We have to talk.

<_Michael needs you. He could feel Karr's virtual eyes passing over the man and Kitt frowned at the subtle familiarity. Karr must have sensed his puzzlement, because he continued. <_And I need my privacy. The more familiar defensive Karr reared its head.

Kitt slipped away from Michael slightly, reassuring his driver with a small caress. <_No, Karr. We need you. Nick needs you.

The darker AI pulled away, but Kitt dug in his virtual heels.

<_Leave me alone!

<_You are not alone! Never alone, Karr!

Kitt had to hold his ground as he was shoved, the other AI desperate for his privacy.

//Karr, please...//

Kitt spun to find Michael standing beside him in this virtual space. Though he was weak, an amber flare of determination flickered in his presence. //Please listen.//

Kitt turned back to his brother and discovered that the older AI had heard Michael. Karr was still streaked with white. The colour would fade as the code was assimilated over time, but for now, it flickered eerily in the dark. He tried to pull away again and to Kitt's surprise a trickle of fear leaked from his brother.

Kitt's virtual eyes widened as Michael suddenly reached out and brushed a tendril of amber across Karr's darkness, entwining it gently with that of the dark AI. //Never alone.//

Karr cried out, but it wasn't fear or pain, but something more undefined. Kitt joined his partner, white merging with amber and black.

They existed like that for a moment in time, silent communication of nothing but emotion.

Then Michael withdrew slowly, the energy required was too much to maintain. Kitt continued to hold on to his brother while simultaneously reaching for his partner, urging him to rest. His driver rebelled, but he didn't have the energy to resist Kitt's subtle caresses, drifting into a light slumber whether he wanted to or not.

Kitt turned back to Karr.

His brother was trembling. <_He is so weak.

<_He nearly died. And you weren't far behind. His tone was sharp and hurting. <_Don't ever do that again.

There were flickers of anger in his brother, his natural defences flaring. <_I am what I am.

<_I can't do this without you, Karr! The other AI flinched away, but Kitt was relentless. His brother needed to stop this self sacrifice. <_We are together. No one is more important than the other. You need help, you ask.

<_Michael was injured.

<_Yes, he was. But he is safe.

<_I didn't want...

Kitt frowned. <_Didn't want what?

<_To interrupt. He needed you.

<_I need you!

<_Not like Michael needs you.

Karr's sudden repeated use of Michael's first name readily amazed Kitt enough, but the urgency in his tone had the younger AI frowning. <_Of course. As Nick needs you.

Something flickered across the darkness. <_He loves you so very much.

Kitt wasn't stunned so much as completely confused. <_Yes...

<_I interrupted it once. I will not again. And the AI pulled away, this time freeing himself from Kitt's grip.

<_Karr! He projected how much he needed his brother, how sorry he was for everything and how much it hurt.