AN: A fic I wrote for portalkink! Obviously this is F/F, so if that's not your cup of tea, this might not be for you!

Additional warnings: Sort of sex-by-necessity, but everyone's happy in the end.

Chell stood with her arms crossed. She was utterly unarmed. She was almost translucently pale from severe lack of sunlight. She was still a little on the scrawny side, as it had been over a century since she'd had a decent meal. She was tapping her foot in impatience, and she was pissed.

"I already told you that I don't intend to keep you here long."

Chell's expression only intensified in its pissed-off-ness, and in response, GLaDOS heaved a simulated and very exasperated-sounding sigh. "I'm not lying to you. If I were lying to you, would we be having this conversation? Would you be standing here, in my hub, talking to me? No. If I intended to recapture you for the purpose of putting you through testing, you'd be doing just that."

Chell was not alone in the chamber. There was a robot with her, a tall, pear-shaped construct with a bright orange eye midway down its torso. It was watching her curiously, a portal gun cradled against what passed for its chest.

It had been almost depressingly simple to capture Chell. GLaDOS had sent the little orange-eyed robot, P-body, out after the girl. Despite its petite frame, it was quite strong, so it had been easy for it to tote a panel liberally coated with portal-conducting gel along. P-body had jogged through the wheat fields around the facility tirelessly, and, once stumbling upon the body of the sleeping Chell, had laid down the panel, fired a portal onto it, and simply pushed her through.

The other end of the portal had led to the facility, of course, and Chell hadn't fallen for a very long distance. They didn't want to hurt her, after all. To keep her from making a speedy escape, they'd had to drop her from a ceiling, though, and she was sporting a fresh and nastily purple bruise on her forehead. P-body had cheerfully jumped through after her and, with the aid of a few persuasive wall panels, had led her to GLaDOS.

Just when she thought she had her freedom, she was dragged back and made to stand before her old tormentor. Truth be told, things could be worse. The room didn't seem to be flooding with neurotoxin, and nothing was shooting at her. Very slightly, she relaxed a bit. Since she was physically incapable of speech, GLaDOS had learned to key in on Chell's body language in order to accurately communicate with her.

"So you're ready to listen?"

Chell nodded slowly.

"Very well. I'm having… a problem with my systems. It's a bit technical, to be honest, and I'm not planning on asking for your those parts of the problem-I know they're quite beyond you-but all the same there is something you can do for me that nobody else here can."

Chell's irritated expression was melting into one of genuine confusion and slight concern. She knew GLaDOS, and there was an edge in the AI's voice that she had never heard before. GLaDOS sounded distressed, anxious. She had been turned into a potato and had been calmer and more collected than this. Though she was making an effort, there was definitely an undercurrent of anxiety there.

"And I know you may not be inclined to be generous towards me, but let's be honest. If I really wanted something from you, I could always take it. Keep in mind that I am not taking it, but instead asking you for it." A pause. "And offering you something in return."

Chell inclined her head slightly, eyebrows raised.

GLaDOS paused uncomfortably, and hunched up slightly, arraying her massive form against the place where it met the ceiling. Chell had never seen an enormous all-powerful robot fidget before. It was an interesting sight. "Previous statements and science aside… I regrettably… require your help." GLaDOS ground out painfully.

Chell stared back uncertainly.

"I do hope you're capable of not murdering everything you touch, because if you do help me, maybe I'll help you retrieve that moron from the depths of space." GLaDOS glanced back to Chell quickly to gauge the human's reaction. Her expression had jumped from vaguely annoyed to stunned in mere seconds. "Maybe."

Chell took a deep breath.

"I saw you try to grab him. At first I thought you were just flailing when I disconnected, but in addition to an excellent memory, I am able to actually play back everything I see, and I clearly saw you make a grasping motion towards him when he was carried off. You wanted to save him, didn't you?" Unsurprisingly, the woman said nothing, but she was doing what she could to suppress the somewhat pained expression on her face.

"Though I personally think you are wasting your pity, I am not above doing you a favor if you do me one. So keep that in mind." GLaDOS relaxed a bit, extending her long chassis from the ceiling and looking decidedly less embarrassed. She clearly thought she had the upper hand here. "I'm telling you all of this to prepare you. I'm offering you a substantial reward, one that will require not only extensive effort and expenditure of resources on my part, but will also require me to push down my utter hatred of that waste of scrap metal. That is not," she reminded Chell, "easy for me to do."

Chell had quite composed herself by now, and waved GLaDOS on, obviously impatient for her to continue.

Still GLaDOS hesitated. This was beyond embarrassing. "The little core damaged my mainframe with his blundering. I'm suffering from a glitch. It's nothing I can't fix on my own, but the nature of the error is making it impossible for me to concentrate long enough to fix it. My assistants…" She swiveled her single unblinking eye towards where P-body still stood at attention. "have tried on my behalf, but they lack the technical knowledge to purge the error from my system. They're still new."

Chell glanced over to P-body, who was still unabashedly observing her, and then back to GLaDOS. She didn't bother trying to hide her grin.

"Don't make fun of me!" GLaDOS immediately demanded. "Even a system as complex as myself suffers from glitches occasionally. And it doesn't help that it was roughly manhandled away from me thanks to someone whose name we won't mention."

Chell shrugged. Point.

"The urge to test is, for some reason, continually asserting itself into my protocols," GLaDOS went on to explain, a bit sullenly. "Testing itself does not satisfy it. I need you to access my system and manually satisfy the conditions of… what did he call it? Of the Itch. It's simple, in theory, but I was never given access to that sort of information, so I don't know how to do it. What's more, it can only be done physically, from a panel in my chassis. I trust my creations, but like I said, they're new. They might accidentally damage me further. They have intelligence, but not experience or intuition. For now, we still need humans for that."

Chell shrugged again.

"I'm assuming that the Itch will make itself known once every dozen minutes or so. I'm unsure how long it will take me to correct the error in my system, but you shouldn't be here for more than an hour or two, depending on how long it takes you to figure out how to work the interface." GLaDOS paused. "I hope you realize the gravity of what I'm about to let you do."

Chell nodded. GLaDOS hadn't come out and said it, but if there was some sort of interface on her body that gave someone direct control over her major functions, odds were it was some sort of admin menu, and it would give Chell the power to completely shut GLaDOS down. For many reasons, that would be stupid. For one, it would mean Chell would be trapped down here and the lab would probably eventually explode, but the option was still there, if she were crazy enough to take it.

And it was a no-brainer as to whether or not GLaDOS thought Chell was crazy.

GLaDOS continued to hesitate, and then, finally, with yet another sigh, began to lower her chassis towards the ground. "Let's hope, for both of our sakes, that you don't have anything stupid planned. Okay, begin by pushing aside those wires, there-"

It was an arduous process, digging through the layers of protection to reach the admin panel. At one point GLaDOS had had to call over P-body to render some assistance, as the robot's dexterously thin fingers could make quicker work of some of the smaller components than Chell's could. Once it was done, the robot picked its portal device back up and stepped away again.

All of their efforts had bared a glowing display in GLaDOS's side. The enormous machine had to sit still in order for Chell to access it. Chell could understand why this sort of thing wouldn't have been any use in their struggle against Wheatley-there was no way they would have been able to open him up in time. Either he would have gotten a lucky shot in, or the facility would've blown before they could even get to it.

There was a tiny, cramped keyboard just below the display. Chell sighed. This was going to be painstaking work. She glanced up once. From her angle, GLaDOS couldn't see her through her central eye, but doubtless she had access to other means of watching Chell. The human wasn't familiar with the particulars of the sorts of system the scientists used, but there was a basic logic that she could apply to the interface.

The functions were listed simply enough, and nothing was further password-protected. It was simply the task of slogging through the menus, tracing down submenu after sub-menu after sub-menu in hopes of finding the proper one. With no further ado, she set to work.

After a while she began to see why GLaDOS didn't delegate the task to the robots. Leaping from menu to menu required tests of a logic that someone with a childlike brain capacity wouldn't be able to pass. They would likely have just run through the system sequentially, which would have taken much longer. Chell had four false starts, but an hour and a half after she began her search, she finally narrowed it down. She reached over and tapped a smooth section of GLaDOS's fragmented outer shell.

"You found it?" GLaDOS swiveled slightly in an effort to see her, and Chell just thrust a thumbs-up into the air. "Thank goodness. It was getting unbearable. Please deal with it, and I'll get to work."

Here Chell paused. There was no function that said, simply, "disengage test requirement protocol" or anything similar. There were a few other options, though. "Reinforce test protocol parameters." Hmm. That didn't sound as if it would help. It would probably make things worse.

"Satisfy test protocol parameters." That sounded more likely. It would be like completing a test. In theory. Chell inhaled deeply, straightened her spine, and highlighted the option. All that was left to do was press the enter key. She leaned over and tapped the portion of shell again to warn GLaDOS that she was about to begin.

"Go on."

Chell pressed the key.

In order for the human to work comfortably, GLaDOS had been forced to disengage some of the apparatuses connecting her to the ceiling. She had been half-resting on the floor of the hub. As soon as Chell pressed the key, every line and curve of GLaDOS's body went rigid and she pulled up and away, nearly knocking Chell over in the process.

The human managed to keep from tumbling over and glared accusingly up at the machine, clearly wanting an explanation. GLaDOS didn't have any sort of shape that accurately portrayed human body language, but if Chell was reading it right, she was having the same reaction.

"What did you do?" she demanded.

Chell gestured towards the still-open panel.

"That wasn't-that wasn't supposed to happen."

Chell cocked her head and shrugged. She wondered if it had worked at all.

"I… well. That's… that's one way to stop it. It worked, but…" Chell's old nemesis was behaving with uncharacteristic anxiety. Chell stood, brushing herself off and wondering what could have caused such a reaction. Had she hurt her? "Okay. I can work with this. Stay there. I might need you." Without another word, GLaDOS half-coiled against herself, obviously concentrating on the task of straightening out her damaged systems.

Chell snorted. It would have been nice, just once, to have been asked to stay rather than told. She didn't have to wait long, though, because ten minutes after she started, GLaDOS obviously became too distracted to continue. She lowered herself to the floor level and demanded, simply, "Again."

Chell trotted over and leaned to tap the button. There was an irregular section of casing that was loosely shaped like a handle, and she gripped it firmly before she leaned in to punch, anticipating that GLaDOS would pull away again. She felt a little guilty about this, if it was obviously hurting her. She didn't exactly like the enormous machine, but she didn't want to torture her.

GLaDOS did jerk away, but because of her grip, Chell was dragged with her. In her scramble to stay on her feet, she did something that was imperceptible to her, but was blatantly obvious to the computer whose systems she was accessing. She depressed the button for one point seven-four seconds longer. GLaDOS made a soft wordless sound.

Chell sprang back gingerly, wearing an apologetic grimace. GLaDOS was silent for a few moments, and then simply said, "Thank you." Before returning to her work. This time Chell was left waiting for closer to seventeen minutes. She had settled herself down on the floor with her hands behind her head, leisurely dozing. GLaDOS approached her abruptly, looming over her and startling the human from her catnap. When she spoke, it was tersely, as if she were annoyed.

"I don't know why, but the length of time I'm left before the test imperative compromises my concentration is directly proportionate to how long you push that button. So I'm going to have to ask you to push it again, and this time for longer."

Chell tilted her head and did her best to look sympathetic with what had to be two tons of sentient steel looming over her. She sat up, and GLaDOS swiveled to the side to expose the panel. "This," the computer sighed, "is so humiliating."

Chell decided it was better to just get it over with, rather than let GLaDOS anticipate it. It was like removing a band-aid, right? The quicker, the better? She leaned in, gripped the improvised handle, and depressed the key. GLaDOS's entire structure shuddered under her fingertips, over her head. It was a little bit dizzying to think that this enormous, powerful, super-intelligent being could be cowed with just the push of a button. Chell still felt guilty. GLaDOS obvious wasn't enjoying this. She was curling as far sideways as her position near the human and the structure of her hanging body would allow, the sensation of pain so great that she had to move to keep it from overwhelming her.

"Ahh..."

Chell's expression froze. Wait a second.

"That's enough. Th-that's enough, stop!" GLaDOS shakily demanded.

Chell drew back completely, pulling her hands against her chest. There was a strained quality to GLaDOS's voice, yes, but it hadn't sounded like pain. It hadn't sounded like pain at all. GLaDOS swiveled to face her. For a moment the two females-one of them tattered and bruised, but definitely human, and the other cold, clean, and metallic, regarded one another. "The… programs responsible for operating my resistance to the test-euphoria are apparently… not working."

Definitely not pain.

"That was nearly four seconds. That should give me close to half an hour. I'll see what I can do." She began to swivel away. Chell watched her for a few moments. If what GLaDOS had surmised about the length of the time she satisfied the test protocols was true, then it would probably be less of a waste of both of their time to give it one good, long push and let GLaDOS work on her problem with no distractions.

Chell decided to do her best to communicate this. She trotted over to where GLaDOS was suspended and rapped at her casing. GLaDOS turned to look at her again, and in that moment, Chell was struck by just how oddly familiar they'd become.

Only days before GLaDOS had been trying to kill her, and now she was responding to Chell's touch as if she had just been tapped on the shoulder. GLaDOS was an enigma and an obviously hostile creature, but she was letting Chell see this vulnerable side of her, even if it was only for practicality's sake. If nothing else, it instilled in the human a sense of respect and a bit of empathy.

Chell reached over and firmly gripped the handle, just standing there and hoping GLaDOS would put two and two together. She put her hand over the keyboard and pantomimed tapping a key. "I'm fine for now." GLaDOS reminded her. Chell pantomimed again, this time holding her finger down over the imaginary key. GLaDOS stared. "Oh," she finally said.

Chell nodded.

The machine hesitated. "There's no guarantee it'll work, but… let's just get it over with." Chell took a deep breath and stepped a bit closer. If GLaDOS was going to start moving like that again, she would need to be prepared to move with her. "This is stupid. I shouldn't have to deal with this. I'm an experienced tester." Chell shrugged and pushed down, having nothing of her own to add. "It's not like-hahh!"

GLaDOS cut off the sound, willing herself to silence. Chell could feel her shaking under her hands. For a few moments the only sounds were the soft whirr of the components holding her in place trying to respond to her conflicting desire to move and stay still. Then, quite to the human's surprise, GLaDOS spoke.

"Ohh," she breathed, "Oh, it's just… it's been so long…"

Chell didn't really know how to respond to that.

GLaDOS lost the ability to form words, her voice dissolving into a low, warm moan of pure contentment. This seemed to mark the end of her reservations, and she vented her pleasure vocally, her voice taking on that curiously musical quality that Chell had heard in the past. Of course, then, she had been yelling at Chell or screaming in pain and horror, not exulting in the indulgence of a long-lost, viscerally dominating euphoria. She was obviously trying to keep still, but had only succeeded in slowing her movements. She writhed in one long, sinuously graceful arch. It wasn't, to Chell's surprise, an entirely unpleasant spectacle to watch.

But it did have to end eventually. Chell wasn't used to pleasuring giant homicidal robots. She wondered if it would be more polite to let her down easily. Hmm. Probably for the best. Doing what she could to steady herself against GLaDOS's languid movements, she began to slowly lift her finger. GLaDOS sighed and stilled, and Chell carefully raised it the rest of the way, releasing the handle and stepping back a bit.

For a moment GLaDOS just hung there. Chell put her hands on her hips, feeling decidedly satisfied. It wasn't often that one got to do something like that. Finally her old nemesis stirred, slowly pulling herself up from where she had leaned against the floor. "Okay." Was all she said, and then coiled up to get to work.

Chell snorted. That hadn't sounded okay. That had sounded pretty damn fantastic, if she did say so herself. Still, it wasn't worth arguing over, and she wasn't going to make it any more awkward for GLaDOS than it had to be.

There was a soft clatter from the other end of the hub. Chell glanced over. P-body was staring, utterly still, at its creator. The sound had been the portal gun falling from its limp fingers. Chell winced and hope she hadn't inadvertently traumatized the little robot.

"I do intend to make good on my offer," GLaDOS said briskly. To her credit, there was barely a waver in her voice, and aside from a slight trembling in certain areas of her casing, she was holding herself admirably still. "After I get this taken care of I will retrieve your friend. But I'm going to make sure he never tries anything like this again."

Chell put her hands on her hips and regarded GLaDOS sternly.

"I won't do anything permanent, I promise." GLaDOS remained still, but the elevator to one of the lower levels began to rise from the ground. "I scraped up some food for you, and some water. Since you're going to be here, you might as well not starve."

Chell shrugged and trotted to the elevator. P-body gathered its dropped portal device and followed. It stepped into the elevator after her. Maybe it was her imagination, because there wasn't much of a face to work with, but Chell could have sworn that the little robot looked thoughtful about what it had just seen.

"I hope you're in the mood for potatoes." GLaDOS called. The door shut and the elevator descended.