Disclaimer: Not mine. I'm just playing with them, and I promise to return them without too much damage.

A/N: I just watched Gemini, and out sprang this fic. Let me know what you think!

Twins

She'd always loved blue Jell-O. From the first time she'd eaten it when she was four, it had been one of her favorite deserts. She also loved mustard, hated peas, and was ambivalent towards the pot roast her mother had used to make and her father, after her death, used to ruin.

She couldn't help wonder if her replicator copy felt the same way.

It was odd, really. Knowing that, somehow, there was another one of her in the universe. Someone who felt in the same way, thought the same way, spoke the same way, shared the same memories. Looking at what Fifth had created, at the machine he had made in her image, she felt dirty, violated, in a way she wasn't quite able to explain. She wanted to hate the replicator, but somehow, she couldn't. She understood its choices, its thought processes, its reasoning. So, since she couldn't hate it, she hated herself. She saw parts of herself in the replicator, more than she wanted to.

So she worked. Worked to ignore the fact that she'd screwed up, that some alternate form of herself was plotting to destroy everything she knew. Had, in some way, already succeeded.

So she worked.

"What are you still doing up?"

Her fingers stilled on the replicator pieces, but she didn't look up.

"Just running some last minute tests on the human form replicator cells, sir."

He slowly walked into the room, not standing in the doorway, but not near her, either.

"You need to sleep."

Sleep was something she was trying to avoid. Her guilty mind supplied her with enough horrific images while awake; she didn't want to think about what she would see if she slept.

"I'm fine."

One step closer. "Are you?" Skepticism and doubt were clear in his voice. She ignored it and concentrated on her work.

"Yes." Her voice left no room for argument. He said nothing. The silence in the room was stifling, but neither spoke. The only movement in the room was the tools in her hands, prying at, in a way, bits and pieces of herself.

"She wasn't you."

He, of all people, would know what was on her mind. The only one who would acknowledge the responsibility, the blame she placed on herself.

"I need to do this." And she did. The work the only thing she could think of to do that would, in some small way, mitigate the harm she'd caused. Nothing could fully erase it, the damage was too great, but it was all she could do.

"Why?"

She knew why. It was her penance, her payment for what he'd done. But she wouldn't, couldn't tell him that.

"A lot of valuable information can be gathered from these cells. Like I said earlier, we've never had an opportunity like this before. We could potentially learn a lot about Replicators from these pieces." And maybe save ourselves from what I caused, she added silently. But she wouldn't tell him that, either.

"Carter." She didn't look up. "Sam."

She slowly turned her head, slowly met his eyes.

"It. Wasn't. Your. Fault." There was no blame in his gaze, only firm conviction. Even that wasn't enough to convince her. She blamed herself more than anyone else on the base, because she should have been able to see it coming. Should have realized that the replicator was manipulating her emotions, using the knowledge Fifth gave her to convince Sam of her sincerity. And, she'd fallen for it.

"I should have seen it coming."

He stepped closer, keeping his eyes on hers. "You couldn't have known."

"How could I have not?" She turned to face him fully, her voice filled with frustration and a desperation she tried to hide. Frustration at her failure, and desperation to fix what she'd done. And somehow knowing that she couldn't.

He stopped in front of her. "Because she isn't you."

She shook her head. "She is. In more ways that I want to admit." And it was true. The replicator was, essentially, her. Everything they shared was the same, from appearances to memories.

"Fifth made her what she is."

She laughed, a cold, harsh sound in the otherwise silent lab. "No, sir. I made her what she is. Fifth only taught her what he learned from me. Everything she knows is what I know. She is me, for all intents and purposes. I did this. You can't change that."

"Carter-"

She abruptly stood, pushing her chair away. "I killed you!"

He stopped. "What?" he asked, confusion lacing his voice.

"I killed you." In a way, she had. It certainly had felt like she had. "When she…showed me what Fifth had done to her. Or, at least what she wanted me to think Fifth had done to her. I- she- killed you."

He shook his head. "You didn't do anything, Carter," he said emphatically.

"No." And she'd finally accepted that it hadn't been her that had fired that shot, even though she'd felt everything as though she'd watched him fall to the floor. "But I may as well have."

"Why do you say that?"

It was those emotions, that grief and guilt, which had made her trust the replicator, a trust that had led to complete and utter disaster. She sat back on her chair, suddenly overwhelmingly weary. "Because right now, we're completely helpless against the Replicators. And it's entirely because of me. And," she continued, seeing his mouth open, "you know it's true. You can't change it. I can't change it." Though, dear god, she wished she could. "I can just try to fix it. I have to fix it." Because if she didn't, they didn't have a chance.

He squarely met her eyes. "We will get through this." He sounded so sure, so confident. So certain that everything would turn out all right in the end, like it always did.

She wanted to believe him, but right then, with the knowledge that she, in some form, was out there planning his and the entire galaxy's destruction, she couldn't.

So she kept working.

But now, he was there, she wasn't alone, and in that one way, she wasn't like the replicator. And that small piece of knowledge, that small difference, gave her just a little hope that, maybe, like he said, they would get through it.

That maybe, she wasn't her.