"Dr. Cormier," Leekie says to her one day, "I have a new assignment for you. It's very important, and highly classified." He passes her a folder. "All of the details are in here."

The scientist quickly skims a few of the papers. "Human cloning?" she gasps.

"Yes," Leekie answers. "We succeeded some time ago. We need you to monitor one."

"What is this 'monitoring'?" Delphine asks.

"Befriend her." Leekie says. "Work your way into her life. But remember, you're doing all this for DYAD, not for your subject."

"Yes," the blonde replies. "I will remember that."

Delphine hears footsteps coming down the hall, and spies her subject, 324B21, in the reflection of the computer lab window. She sniffles, drawing up her best fake tears. She needs to make this convincing if she wants to pull Cosima in. From what Delphine has read, Niehaus is a caring person, and giving her someone to comfort seems like a good hook.

She hears the footsteps come to a halt, and feels a hand touch her arm. A part of her marvels at the tactile reality of this human clone.

"Hey…sorry! You just forgot this in the lab, sorry," Cosima says quickly, and starts to walk away. Delphine thanks her, feeling her heart begin to sink at the abrupt departure, when her subject turns around.

"But, full disclosure, I, um, did peek," Cosima apologizes. "You're French, you have killer grades." Delphine smiles and laughs. Leekie had assured her academic excellence would pique 324B21's interest.

"Thank you, um, oh god, I'm so sorry, I'm not usually like—like this," the blonde says.

"Oh, bad break-up?" Cosima asks, looking sympathetic.

"Yeah, well, we're an ocean apart, so…" Delphine lies easily, biting her lip.

"Yeah, long distance never works," the clone replies, shaking her head. "Um, you're in microbiology too, right?"

"Yes, immunology," Delphine says. "I study host-parasite relationships."

It takes a few days, but Delphine is able to track 324B21 down to the school's library. The scientist thinks that the first encounter went well, but knows she needs to engage her subject again to create a more secure attachment. She has to be more than a classmate, she needs to be a confidant. How else would she gather valuable information to send to DYAD?

Delphine sits within easy view of Cosima, watching her out of her peripherals. The girl keeps sneaking glances at her, and the blonde is careful to keep the expression on her face neutral as the student gets up and walks towards her.

"Hey, Delphine," Cosima whispers.

"Hey, bonjour Cosima," Delphine replies.

"I'm bored," the brunette says, exhaling through her nose.

Bien, Delphine thinks, and replies. "Well you know there's this lecture that I was going to see." She rifles through her carefully careless papers. "Wait, where is it…um, I was going to, if you want to come with me," she finishes, handing Cosima the Neolutionism flyer.

"Neolutionism," Cosima says, skeptical. "Really?"

"You've heard of it?" Delphine is genuinely surprised. Leekie will be excited, it seems their subject has gone deeper than expected.

"Yeah, it's kinda fringe, don't you think?" Cosima asks.

"Well, I think that as a Darwinist, it would interest you." The blonde draws a breath, calculating. "And this Dr. Leekie is a really, really interesting speaker—I saw his TED talk online and uh," Delphine exhales, looking up. "So…"

"Sure, why not."

Delphine tells Cosima she needs a cigarette, and steps outside into the school courtyard. Looking around, she spies a deserted little alcove, and steps inside, grateful for the protection from the brisk Minnesota air. Taking out her cell phone, she dials a number she has long since memorized.

"Dr. Cormier," Leekie says, genial as ever. "I was wondering when I would hear from you."

"I have made contact with the subject," Delphine says, voice low. "She agreed to go to the Neolutionism lecture with me tonight."

"Excellent," Leekie replies. "Good work, doctor."

"Aldous," the French woman starts. "I think that 324B21 may have done some digging."

"Digging?" he replies. "How far, Delphine?"

"I do not know," she says, "but I intend to find out.

As Leekie speaks, Delphine keeps close track of Cosima's reactions. She marvels at how she has gained the clone's trust so quickly. She had only had to offer a hint of friendship, and 324B21 had followed her exactly where Delphine wanted. Passingly, she wonders how lonely the girl must have been, but dismisses the thought quickly.

Cosima laughs at Leekie's jokes, but Delphine senses she is still uneasy. Even so, she is surprised when the brunette mouths off to Leekie after he speaks of fixing her vision.

"Maybe I'll just start with basic Lasik," Cosima deadpans, and the crowd laughs. To his credit, Leekie recovers quickly and gracefully. Delphine is relieved.

The lecture finishes, and the scientist starts to formulate a plan to get Cosima to Leekie. It will be simple enough, she thinks. Where I go, she seems to follow.

"Cosima, oh my god look," she whispers. "There he is. I would just love to meet him."

The student looks doubtful and half-embarrassed over how star-struck Delphine is, but she comes when the blonde waves her over. There is no controlling Cosima's reactions, however, and Delphine is almost scandalized when the other woman calls bullshit on Leekie's assertion of a neauolingual chip. The DYAD director takes it in stride, not once breaking character.

"Good. A skeptic," he smiles. "Neural implants are something we're exploring, however."

"At the DYAD Institute," Delphine butts in helpfully. She wants that name to get stuck in her subject's head.

They make small talk about the "freaky Leekies" until the French woman is able to steer the conversation to a place where her boss can engage Cosima.

"You know, I'm in immunology," she supplies.

"And you?" Leekie asks, looking at Cosima.

"Um, evo-devo," Cosima replies. "So whenever somebody talks about the future, I always say show, don't tell."

Delphine once again feels her stomach flip at the clone's impudence, but is proud she is the first to have allowed Leekie to interact directly with one of his experimental organisms. She knows this will help secure her place at DYAD, and as Cosima's monitor.

"Please, have another look at DYAD," Leekie says, and gives Cosima his card.

Delphine smiles to herself as she walks to her apartment after leaving Cosima (and her stolen bottles of wine) behind. She has had a good time, she realizes, and confirmed herself as Cosima's friend. The girl is smart, funny, and sparkling with life and laughter, and Delphine thinks that if circumstances were different, she might truly be her friend. Those are dangerous thoughts, Dr. Cormier, she stops herself. To go down that road would risk skewing her results with personal affection.

Delphine remembers considering Cosima over the top of her cigarette, a glance she had not intended to be so lingering. Her subject is truly beautiful, the blond thinks, and she does not just mean in the scientific miracle of her existence. Delphine marvels at the remembrance of the skin over muscles and tendons, the angles and planes of a face she is becoming more and more familiar with.

Cosima, she thinks. The cheeky, brilliant, incredible clone. Delphine wonders how she can put such intangible things in her nightly report. Perhaps, she ponders, that is not possible.

The next time she and Cosima meet, it is over lunch, at a hip vegan place Cosima had personally assured her was "totally rocking". Delphine feels her brow furrow over some of the unfamiliar words.

"What is this, this falafel?" she asks Cosima. "I do not recognize this word."

"Oh, it's—that's really good!" Cosima answers. "It's like this ball-thing made out of chickpeas, and then fried. Um, that sounds kinda weird, I know, but they serve it with pita bread. We could share it." She looks up at Delphine, hopefully.

"Sharing is good," Delphine says. "It has been a while since I had anyone to share food with."

Cosima smiles at her shyly. "Yeah, me too."

"So," Delphine starts, "tell me about your life, about what is happening. School must be getting pretty intense, non?"

Her subject laughs. "You know, school is really the least intense part of my life right now," she says. "But it's a nice distraction from all the craziness."

Delphine senses she's close to something big. I have to play this right, she thinks. "You seem like you're so serious at school, what could be that big a distraction?"

Cosima looks at her for a second, something playing behind her eyes. Is it regret? Delphine feels the strangest urge to caress her face, but takes the other woman's hand instead.

"You do not have to tell me if you do not want," she says, surprising herself. "I am just her to listen as a friend, that is all."

Whatever was happing before, the moment is over now. Delphine wonders why she had stopped probing, protecting Cosima's privacy. She only knows that it seemed like the right thing to do.

"It's alright," Cosima says. "Just weird life shit, you know? I'm glad to have you here with me, though." She glances at their joined hands, and Delphine moves hers, embarrassed. She hadn't realized she'd had it there that long.

"I am glad to be here," she murmurs. "You are an interesting girl, Cosima."

Delphine does not make her call to Leekie that night. Honestly, she does not know what she would say to him if she did. She is a scientist. She is supposed to remain objective! And yet she is finding that she cannot remain that way with Cosima—subject 324B21. "Merde," she curses. I thought I know what this was, she thinks, but the truth is she had no idea at all.

She had lured Cosima into a dinner with Leekie, and afterwards Delphine is very nearly certain that the clone is self-aware. She worries that she has pushed Cosima's suspicions too far with Dr. Leekie "coincidentally" showing up. Cosima, for her part, is pouring the wine while looking at the DYAD Institute's card.

Still, Delphine pushes harder. "Working with Dr. Leekie could be the opportunity of a lifetime," she says.

"I know, I know," the brunette replies.

"Then why are you being so coy?"

"Don't you think…it's time that we admit what this is really about?" Cosima says, and Delphine feels her heart leap into her chest. She knows! She knows that I am her—

Cosima draws closer and kisses her. It's soft, and sweet, and Delphine's hand comes up to cup Cosima's face even as she pulls away. The other woman backs up, flustered. "Oh, oh god, Delphine, I, did I make a huge mistake?"

"I have to go," she replies, and practically runs out the door. The scientist keeps hurrying until she's outside the apartment complex, short of breath. She tells herself it's just the cold. Her head is spinning. "Mon Dieu," she breathes. "Mon Dieu."

Intimate relationships with their subjects were touched on in the briefings Delphine had read about being a monitor, but she never thought it would apply to her. She is not a gay woman, after all. The blonde touches her fingers to her mouth. She can almost still feel the sensation of Cosima's lips against hers. The shock is gone now, and the French woman cannot place what it is that she is feeling.

Delphine smokes a cigarette after Leekie drives away. The older man had made two things clear: that she must be intimate with Cosima, and that Cosima's life is in danger. She does not know which scares her more.

There is a fluttering in her stomach Delphine tells herself is only nerves as she walks up to Cosima's apartment. She is prepared, she tells herself, she has read up on how to make love to a woman, and Cosima herself is beautiful. I will do this, and keep her safe, Delphine thinks, and knocks on the door.

"Hey, Delphine," Cosima greets her gently.

"I hope I am not disturbing you," she answers, and Cosima reassures her that she isn't, then launches into a quickly spoken apology.

"I know, I know, I know, you're not, you're not gay. And I'm a total idiot. I'm so sorry."

This is her out, Delphine knows, and for a moment, she takes it. It's easy to retreat back to the science, comfortable, familiar. She are Cosima are so quickly back to normal, pouring over papers, and Delphine feels something click into place.

"You know it's really really good to finally meet someone who gets it," she says. "Who gets…who gets me." Delphine doesn't even realize the words are true until she's said them.

It's almost easy, after that, to cross the line she had been so afraid of. "I can't stop thinking about that kiss."

"Uh, like, in a not bad way?" Cosima asks, hopeful. Flustered, Delphine finds herself reverting to the science again.

"Oh like, I have never thought about bisexuality. I mean, for myself, you know. But as a scientist, I know that sexuality is, is a spectrum. But, you know, social biases, they—they codify attraction. It's contrary to the biological facts."

"That's…oddly romantic," Cosima says, pausing. "Totally encouraging."

Delphine caresses Cosima's face with her hand, like she had wanted to do in the café, a few weeks ago. She passes her thumb over the other woman's lips, and then lunges forward in a kiss, too quickly to lose her nerve. Cosima is soft underneath her hands, softer than Delphine could have imagined, as she pushes down her sweater. The smaller woman's lips press, insistent, and Delphine opens her mouth into the kiss as Cosima pulls her down on top of the desk.

Delphine loses herself in the sensation, running a hand up and down the brunette's side, feeling the shuddering intake of breath when her hand brushes close to Cosima's chest. Cosima's hands are slower, gentler, almost hesitant. Delphine can feel a heat spreading across her from where they rest on her back.

"Cosima," Delphine breathes. "It is okay. I…" She can only trail off, distracted, as the other woman's mouth moves to her neck, kissing gently along her jawline before latching onto her pulse point and sucking, hard. "Oh."

"Delphine," Cosima murmurs against her throat. Her hands are wandering more freely now, passing from the sides of her breasts to the French woman's ass. Delphine is surprised by the want she can feel starting to course through her.

"Merde," she gasps, and feels Cosima's hands squeeze. She rests one hand on the desk behind the brunette. I did not know it would be like this, she thinks, this heat…

Cosima is shifting beneath her now, placing one leg between Delphine's and bringing their hips together. Delphine sucks in a breath at the contact. "Is this okay?" Cosima asks, worried, and in response Delphine grabs the back of her neck and pulls her into a bruising kiss.

"Oui," she whimpers when they break apart and Cosima lifts her leg up into her center. "Oui, yes, oui."

Delphine's sweater is feeling far too hot, and she moves back to take it off. Cosima places her hand on top of hers. "Let me?"

The French woman nods, and Cosima stands up and slowly pulls her shirt over her head. "Wow," she breathes. "You're, you're beautiful, Delphine."

The scientist blushes, fights the urge to cover herself with her hands. Instead, she draws up her courage, and asks "Shall we go to the bed?"

"Yeah." Cosima takes her hand. "We'll go to the bed."

When they get there, Delphine sits down awkwardly, sliding off her boots to avoid looking at Cosima. "I'm sorry," she says. "I don't really, I don't know what—"

"Shhhh." Cosima presses a finger to her lips, leaning the blonde back against the sheets and settling comfortably on top of her. "It's alright. We'll take it slow. And we can stop—"

"No," Delphine replies, finding Cosima's leg between hers again. "I do not want to do that." She begins to pull up Cosima's undershirt, and the shorter woman sits up to give her access. Carefully, Delphine kisses her way up the exposed skin. Cosima's breath is a shuddering gasp.

It is not long until skirts have been discarded too, and both women are lost in the feeling of kissing each other, skin on skin. Cosima grinds down into her, and Delphine feels her arousal spike. She groans, and Cosima moves to take off her bra.

"Wait," Delphine says. "Wait. I'm sorry, I'm sorry, I'm just not ready for that."

Cosima's eyes are understanding. "Underwear stays on, no problem." Her hand settles on Delphine's breast, squeezing lightly. "Is it okay if I do this?"

"Oui," she manages, arching her back into the sensation. Cosima's other hand ventures lower, until it rests just above the waistband of Delphine's underwear.

"And this. Is this okay?" The blonde considers only seconds before giving into the feeling.

"Yes. Yes," she says. "Baise moi, Cosima."

Delphine doesn't know whether or not the other woman understands, but her fingers go where Delphine needs them most. Feeling Cosima's touch, Delphine marvels at how wet she is. Cosima's fingers circle her clit one, two, three times before sinking into her, first one, and then two. Delphine can feel herself unraveling as Cosima builds a steady pace, and when the brunette curls her fingers just right there, she comes apart with French curses spilling from her lips.

Delphine falls back on the pillow, Cosima settling down at her side, arm across her waist. Delphine finds her breath, and tries to stop the swell of emotions rising within her.

"You okay?" Cosima asks.

"Yes," she replies, and begins to cry. It's only now, lying here with this beautiful, generous, wonderful woman that Delphine begins to comprehend the horror of what she has done. She had infiltrated Cosima's life, slipped past all of her defenses, and taken every little piece of her she could to sell away to DYAD. How fitting that my study is of host-parasite relationships, she thinks, for I am the parasite here.

Her newfound conscience does not stop Delphine from further deceiving her lover, and going through her things merely moments after their intimacy. It is to keep her safe, Delphine defends herself internally, but the guilt settles into a pit in her stomach, holding her back when she learns of the child.

"Sarah Manning. Anything else on her?" Leekie asks, and she tells him there is nothing. She is already in too deep, but Delphine can find no way to justify to herself bringing in a little girl. She only hopes Cosima can forgive her for all the rest.

It's a short few days later when Cosima shyly asks Delphine on an actual, proper date. "I know it's a little backwards since we already, you know," (several times, Delphine thinks contentedly) "but um, do you want to go out with me? Like, to do something totally sappy and romantic and dumb like that."

"I would love to," Delphine says, and that is how she finds herself in ice skates, holding Cosima's hand and going very slowly. She squeaks a little every time she wobbles—which is often.

"I would have thought you'd have skated before, growing up in France," Cosima laughs. "Is this seriously your first time?

"Oui. My mother, she always thought it was too dangerous, you know," Delphine says. "She said I was too smart to fall and crack my head."

"That's kind of adorable," the brunette replies, eyes twinkling. "But I promise I won't let you fall and crack your head."

Delphine squeezes her hand, and slowly she starts to get her bearings. Carefully, she lets go of Cosima and skates forward a few feet. "I did it!" she exclaims. "I did the skating!"

"Totes," Cosima agrees, and then skates closer and pulls Delphine into a gentle kiss. "Careful," she says, "don't lose your balance."

"You are very cheeky," Delphine admonishes, but doesn't disentangle herself from her date's embrace. "Very, very cheeky."

"You did say that's why you like me," Cosima grins. "Now try to keep up. I'll go slow." And with that, she skates away.

Delphine spends the rest of the afternoon chasing after Cosima, who rewards her with a kiss whenever she catches her. Afterwards, they settle down with a cup of hot chocolate each at a charming little café. Delphine feels warm and fuzzy, and does not think it's all from the steaming beverage. I think I am falling for this girl, she realizes. Oh, what will I do when she finds out?

Breaking out of her contemplation, Delphine says "I had so much fun today. Perhaps I could plan the next one?"

"I think I'd really like that," Cosima says, lighting up. "That'd be totally cool. I'm so down. I'm downer than downtown down."

"I know this wonderful bakery," Delphine replies, giggling at Cosima's silliness. "I could bring you some truffles, and then we could go to the museum. Are you free Tuesday? I have no classes to TA that day."

"Tuesday works," Cosima says. "I'll see you then."

"Bonjour, ma chérie," Delphine says, walking in through the doorway and kissing Cosima. "I have the truffles that I promised you." She notices the other woman is uncharacteristically silent. "You okay?"

"Are you?" Cosima replies, flat. Delphine feels something start churning in her stomach.

"Well I was, but…" Cosima turns the laptop towards her. The scientist stares at a picture of herself with DYAD's staff, and knows it's over. She's been found out. Cosima was too smart to hide it for forever.

"Delphine Cormier, not Beraud. You've already got your doctorate in immunology, don't you?"

Delphine sinks to her knees. "I'm so sorry," she half-whispers, not trusting her voice.

"I'm so stupid," Cosima replies.

"No, no, no you're not." Delphine reaches for her, but the brunette pulls away. "You knew this all along."

The blonde can only watch helplessly as Cosima lists out all her lies. "Yeah, that transcript you left behind. You fake boyfriend in Paris. Pretending you didn't know who Dr. Leekie was. I knew it was all bullshit, but I still thought you were on my side." Her voice cracks. "I wanted to trust you."

Delphine has to make Cosima understand. There was no other way! She gets up, comes and kneels in front of her. "I had to! Look at me. He says you're in danger!"

"Of what?" Cosima yells. "Do y—you don't even know, do you?" Delphine can only shake her head. "Then you're the real danger, Delphine." Cosima gets up and strides angrily to her room, pulling out a suitcase and beginning to throw clothes into it. The French woman follows helplessly.

"Please, Cosima. Where are you going?"

"Why, so you can tell Leekie?" The worst thing is that there is no venom in Cosima's tone, only resignation. "I'm such an idiot. What else did you tell him?"

"Nothing!" Delphine says emphatically. She takes a gamble. "Just the seven names. Nothing about…Kira. She's an anomaly, you know that."

It doesn't work. Cosima only grows more incensed. "Delphine, you can use me, that's fine." No, it's not, Delphine desperately thinks. "But don't go near that little girl."

"I didn't, and I won't!" she cries.

"Get out!" Cosima shouts, pointing.

There is only one thing left to try. Delphine lays her heart bare to her former lover. "Please, listen to me, just let me—" She reaches out to Cosima, who turns away. "—tell you this one thing. Just listen to me." Cosima looks at her.

"I didn't want to fall for you, I wasn't supposed to. But I have."

"How can I possibly believe that, Delphine?" Cosima asks, brokenly.

"Because you feel it!" Delphine knows it's true, it has to be true. "This is not, it is not a lie. It's not possible. You know I've never been with a woman before—"

"Yeah, it showed," Cosima shoots back.

Delphine feels as though her heart has been stabbed in her chest. Cosima wants to hurt her. There is nothing she can do here. She gets up, walks away. As she leaves, she can hear Cosima sobbing. Delphine hates herself more for being the cause of that pain. When she's in the hall, she leans against the wall and sinks to the floor. Tears of her own start. My god, she thinks, what have I done?

By the time she has reached her apartment, Delphine's despair has hardened into resolve. She has to follow Cosima. Technically it is her duty as a monitor, but Delphine is beyond that. She has to do this for herself, and for Cosima. She must feel it too, Delphine tells herself. And I have so much I could offer, so much information about DYAD. I could give something back. I could be on her side.

There are two places Cosima might go. To her parents in San Francisco, or to her cloned sisters in Toronto. "Merde," Delphine hisses, as she realizes the wrong choice could destroy everything. She must be going to Toronto, Delphine decides. To warn them about…to warn them about me. The guilt is stronger now than it ever was.

Delphine pays for her travel ticket out of pocket. She does not want to alert DYAD to Cosima's movements. She cannot stop them for forever, but she can at least buy her time. She can do that much.

What will I even say to her when I see her? the scientist thinks. She knows she will have a long plane ride to figure it out.

Delphine walks up the alleyway to the apartment whose address she had stolen from DYAD's files. She hopes it is the right one. She passes through the heavily graffitied hallway, and knocks on the door, which slides open.

"Oh. Now I get it," a tall, slender man with dark hair says, giving her the once-over.

"Um. Is Cosima…"

"It's Delphine," the man turns and yells. "She's got baggage."

Cosima walks out, and the blonde feels her heart catch. The man turns and stalks away, and Delphine walks into the apartment. "You know, if Sarah were here, she'd kick your willowy ass," he says, and leaves.

"I promise you I did not tell Leekie about Sarah's child," Delphine says.

"What difference does it make?" Cosima replies tonelessly. "Why are you here?"

"Because I—" Delphine stops herself. Cosima would only push her away. Back to the science, she thinks. The science is safe. "Because Leekie is a liar, and I think you can prove it scientifically with that—" she gestures with her chin, "—your synthetic sequence."

"He gave me my whole genome."

"Yes. But you, you can't find that sequence anymore, can you? He would have scrubbed it."

Angrily, Cosima pushes her papers off the table. Delphine raises her arm to comfort her, but the brunette jumps away.

"Don't."

"I'm on your side now. Please believe me," Delphine whispers. "You need to trust someone."

"I think the sequence is a message." Delphine feels hope flare in her chest. Cosima is letting her in. "Um, like, Dr. Craig Venter watermarked his synthetic DNA. It's a key to our origins."

"May I?" Delphine asks, and Cosima nods.

They spend hours poring over the clone's genome. As the time passes, they become more natural, and Delphine gradually moves closer to Cosima. It almost feels like it had before Cosima had kissed her, and everything changed. No, Delphine realizes. It is not like that at all. She is a person to me now.

When they finally crack the code and figure out Cosima's synthetic DNA sequences are written in binary, Delphine could almost kiss her. The room feels electric with their shared excitement, but she holds herself back. Now is not the time. The feeling fades away when they realize just what that code says. 'This organism and all derivative genetic material is restricted intellectual property.' Mon Dieu. Delphine is horrified with herself. How could I have ever worked for these people? How could I ever have betrayed Cosima for this?

She processes her shock as Cosima calls Sarah and tells her to run. And then Cosima settles next to her and says "I'm sick, Delphine." She looks at her, about to cry, and all Delphine can do is hold her.

No, that is not all I can do, Delphine realizes, much later, after she has taken blood samples from her lover and Cosima has fallen asleep, curled up against her. She looks down at the sleeping woman, smiling at the gentle expression on her face. She looks so peaceful in sleep, away from conspiracies and illness and death. Delphine wonders why she has never watched her like this before, and realizes that Cosima has never been so vulnerable with her.

I will not take this, Delphine thinks. I will not take any more from her. I cannot give back what I have stolen, but I can save her.

Delphine is an immunologist. She is a doctor. She studies host-parasite relationships, and she will not let this disease steal the woman she loves. She promises herself she will not stop until she has succeeded.

She brushes her lips over Cosima's forehead, kissing her gently. Tomorrow, she begins anew.

...

A/N: Wow. This was a big one to write in two days. I had this idea as soon as Delphine mentioned she studied "host-parasite relationships" in her introductory episode. What a great descriptor, I thought, for how their relationship starts! And then this happened, 5000 words later.

Also, yay plot-relevant sex scenes! It was my first to write. Maybe one of these days I'll write one of those "several" Delphine mentioned...