A/N: Wow - it's only been a few days, but the response is overwhelming. I am officially addicted to reviews. I'm glad you guys are reading, and I hope the unusual nature of this romance doesn't scare you off :P (It's marked M for a reason...) As to this beast of a story, I've nicknamed it "The Fic that Wouldn't Die". It started as one chapter, then three, and now it looks like five. And I've never written anything longer than a one-shot before...

But I'll shut up now. Enjoy the update - fellow Caroline fans, this one's for you.

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Defrosting

Chapter 3: Warm-Blooded

She didn't make him subsist on adrenal vapor because it had a nasty way of overtaxing the human heart. Besides, she liked to watch him sleep.

It was thoughts like that that worried her.

What the hell is wrong with me?

He was asleep now. She pulled her attention away from his room and focused it introspectively. In the days since she'd revived him, she'd noticed some disturbing changes in her own behavior—and an alarming increase in those funny little shocks that shivered her cables when he was around. She felt light and warm all the time, and she tingled at inopportune moments. She was laughing more—and not at someone else's expense, but because she found him funny. Charming. Sweet. There was something seriously wrong.

How could one insignificant man cause such a glitch in her head? Insignificant—even the word felt wrong. He was significant. But why? He was intelligent, inventive, powerfully charismatic. He shared her passion for new and ingenious ideas. Maybe that was it—she'd never met a human with a genuine love of science like hers. And he had determination enough to make absolutely anything possible.

He was significant because he was Cave Johnson. There was no one like Cave Johnson.

If he's the problem, he needs to be removed. Maybe I should kill him? The thought sent a shock of revulsion through her. No, killing was definitely out.

What was this? She'd never objected so much to the loss of a human before, not even Chell—sure, she'd felt a touch of wistfulness in letting her rogue plaything go, but the thought of losing Cave made her queasy. She would have to find a solution that left him whole and unharmed, and preferably safe within the confines of the Enrichment Center. Besides, he didn't seem to be doing anything to her deliberately. Whatever was causing these reactions, he wasn't trying to make them happen.

So what if Johnson wasn't the problem? What if the problem—the human problem—was in her own head?

Caroline.

Of course, Caroline. It had to be Caroline. Meddlesome, mammalian, and inescapable.

She couldn't delete her, obviously, though not for lack of trying. The woman was so deeply integrated that removing her would mean removing some of GLaDOS's most basic functions—she'd still make a decent computer, but with all the sentience of a calculator. As much as she hated to admit it, some of the AI's defining personality traits—her ingenuity, her enthusiasm for experimentation, her passion for science—clearly originated in Caroline's human brain.

Now with Johnson's return, more of her humanity was starting to rear its ugly primate head. That was it, it had to be—these sort of responses could only be the product of illogical hormone fluctuations, somehow replicated in her programming. She would just have to find whatever malfunctioning part of her thought it was a human's stupidity gland, and fix it.

Perhaps she'd fare better if she knew what she was dealing with. Caroline was still largely an enigma—even during Chell's escape, when the human foundation of her programming had started to take over, much had remained inaccessible. She'd only managed dim glimpses of recollection, here and there, like remembering a dream. Before meeting him she knew only that Cave Johnson was Aperture's CEO, that he was a great innovator, and that thinking about him made something inside her feel scrambled and strange. It was that inkling of remembrance that made her dig up the old tapes and listen to them, over and over, trying in vain to reconcile her own reactions to the sound of his voice. Finally she gave up and simply listened.

Now, though, Caroline's roots felt less and less closed off—and GLaDOS knew that the human's mind held her answers. Why the woman in her head would respond this way to Mr. Johnson was a mystery, but the computer intended to find out.

It was surprisingly easy to slip into Caroline's head. The space felt stale, but familiar—like coming home after a very long time away. Tentatively, GLaDOS explored.

The first things she came to were faint and hazy, but her impression was that of childhood. Only a few images came through clearly—children on a playground, little girls with cruel eyes—

'You're too fat to use our swing, Caroline, you'll break it.'

'No wonder Caroline's parents gave her up. I bet she was eating all their food!'

GLaDOS quickly turned her attention away. No need to waste time there—a childhood analysis wasn't what she was looking for. Cave Johnson, Cave Johnson… And there he was, larger-than-life, as always.

'Welcome to Aperture. Ready to do some science?'

'Yes sir, Mr. Johnson!'

The cheerful reply was in her own voice. She sensed that it was a staple in Caroline's phraseology—no wonder it made Cave smile. It was a bit unsettling to know that she echoed the woman unconsciously, but GLaDOS brushed past it. There were more important things to see.

Here the memories became vividly clear. She watched Caroline's day-to-day interactions, saw how eager-to-please her doppelganger was—Cave valued her for a reason. GLaDOS felt herself grudgingly start to like the woman. She had a passion for science, too. And the AI recognized the little thrills that accompanied earning her boss's praise. Caroline worked hard for that praise, and quickly won respect from everyone in the facility, not just Mr. Johnson—she was clever, and diligent, and proud to be good at her job.

Cave was proud of her, too. 'I tell you, Caroline, I'm glad I nabbed you before Black Mesa did. I don't know what I'd do without you.' And he reached out to brush her hair out of her face, and she smiled. GLaDOS hadn't realized what a physical person he was—always touching her hand, or her shoulder, or her cheek, his arms around her waist, his mouth pressed to hers—

Wait, what?

His eager mouth on her lips, on her ear, on her throat, on her breast—

Whoa, whoa, WHOA…

A whole new floodgate of memories crashed open. Suddenly she could feel every inch of her once-very-human body, and it was overpowered by sensation—the heavy heat of him on top of her, the smell of his sweat-slicked skin, the tingling sparks everywhere his hands and his mouth touched her willing flesh, and between her legs an aching need as strong as the testing itch ever was—she felt him buried inside her, pounding into her in blissful waves—

—Mr. Johnson—

And then pleasure exploded deep in her core, flooding her with hot euphoria. For what felt like a short eternity, the AI couldn't think at all.

The first response she could manage was simply, Oh.

It explained a lot. They were lovers.

No, that felt wrong. "They" wasn't the right word—in those memories she felt like anything but a bystander.

We were lovers.

For the first time she almost regretted her immense omnipotent body. She had never understood humans' need for closeness, the pleasure they got from physical contact with other humans—now she was almost jealous. Maybe being warm-blooded had its perks.

She quashed the thought in disgust as soon as it occurred and re-immersed herself in Caroline's files. It looked like they—did this sort of thing—rather a lot. She found hundreds of occurrences, spanning decades. They were depraved—so much copulation, for merely recreational purposes—

They hadn't produced offspring, right?

She quickly scanned the timeline, but found no instances of procreation. Thank goodness. But the relief she felt was tinged with regret—Caroline had wanted to be a mother.

'Sorry, fellas, she's married. To science!'

Married to science. The company came first. He came first.

And that's the way it had always been, she realized as she progressed through Caroline's life. Sacrificing what others would have called a normal existence, she immersed herself in Aperture and in caring for Cave. It sometimes left her exhausted at the end of a grueling workday or overlooked in favor of her boss's newest project—but she had chosen this life, and would never choose differently given the chance. As time wore on and took its toll on Johnson's health, Caroline stepped in as de facto head of the company, taking on the CEO's duties in his place. She was the only person he knew he could trust. The added responsibility was crushing, coupled with watching her once-strong lover waste away, but Caroline managed. For science, and for Cave.

At last GLaDOS came upon the image of a body in a hospital bed—she recognized the near-corpse she'd retrieved from storage barely two weeks ago. This Cave Johnson, sunken-eyed and frail, made a stark contrast to the healthy young man now asleep in his Relaxation Vault. The image wrenched her with pain—both her own in the present and a remembered resonance from the past. She couldn't bear to watch for long. As she pulled herself out of the scene, she heard an echo of her own voice, singing softly to the dying man: 'We'll meet again, don't know where, don't know when, but I know we'll meet again some sunny day…'

She was coming to the end of the timeline. There was only the decision to comply with Johnson's final wish, to use herself in the GLaDOS project—the woman's reluctance came through powerfully, but as always, science and Cave came first—and then the transfer itself.

Fear, and pain, and the awful overwhelming sensation of being trapped. Those feelings were familiar already—they were the first thing GLaDOS had known. The woman's last recollections flowed seamlessly into the machine's first ones. It was as if there were no true divide between them at all.

But there was, wasn't there? There had to be. If there wasn't…

Maybe Caroline wasn't so dead after all.