The cold medications take affect almost immediately, and Cosima is dissolving into a puddle of hysterical giggles when you return from the store. (Ice cream in tow. Eskimo Pies, like Cosima requested.)

Sarah gives you a half-amused, half-concerned look when you enter through the sliding door of Felix's unique studio apartment. "The drugs kicked in," she briefs you. "No wonder Alison was into these – from the looks of Cos I'd say they make ya feel pretty good."

That's the point, you want to say. The drugs won't cure her – of course not, it's not that simple. But they'll make her comfortable, ease her pain while you search for the real cure.

And you will find it.

"Mm," you murmur, taking in the image before you. Sarah has a thermometer in one hand and is trying to press the other to Cosima's forehead. Cosima's developed an on-and-off fever and sometimes sweats the whole night through with no rest.

"Delpine," rasps Cosima, all grins as she dodges Sarah's motherly hands. "You look – wow," and she bursts into nervous giggles. You smile.

"You just saw me five minutes ago, ma chérie," you remind her gently. "I looked the same then as I do now." She blinks owlishly at you from behind her glasses.

"I know. But you just look better and better every time I see you." Sarah, who has given up trying to take her sister's temperature, rolls her eyes heavenward, a look of absolute suffering on her face. You smirk.

"I brought ice cream," you say airily in hopes of a change of subject. Cosima's eyes get huge. "Aw, dude, yes! I love you."

"You're welcome to have some as well, Sarah," you offer to the rougher clone, but she waves you off and grabs her jacket. "Nah, that's okay. I gotta meet up with Paul. See if he's got anythin' on where they might've taken Kira."

"Still no progress?" you ask sympathetically. It's been a week with still no sign of Sarah's daughter or foster mother. Now that you really look at her, you can see the lingering pain in her eyes that she otherwise hides so well. It's the same wounded look Cosima had after she found out….

You clench your fist and refuse to think about it.

"Delphine!" Cosima shouts urgently, and you jump, turning your attention to her. The dreadlocked clone squints at you.

You frown. "Yes, Cosima?"

"How do you get your hair to do that?"

Your frown deepens, this time out of puzzlement. "Do what, ma chérie?"

"You know. That thing." She waves her hands around the general area of her own hair for emphasis.

"I'm afraid I don't know what you mean."

"It's fuckin' magical, dude. You're like a – like a fuckin' unicorn or something."

Sarah snorts loudly. "I'm takin' that as my cue to leave," she tells you. "Good luck."

You get up to meet her at the door. "Um, Sarah-"

"What is it?"

"I…. th-thank you. For helping take care of Cosima, I mean. You've already got so much to worry about." You stare at the floor.

She smiles at you, and it boggles your mind because it's Cosima's eyes and Cosima's lips but it's not Cosima's smile. These women are truly a marvel to you.

"It's not a problem. 'Course I care about Cos. I mean, I been lookin' for my family my whole life and I'd say she and Alison count, yea? I'll fight for 'em 'til the end, if I have to."

Not only is it the most you've ever heard the hard, angry woman say in one sitting, but it's also the most heartfelt. Sarah seems to realize this as she clams up suddenly and turns a bit pink in the neck.

"Uh, well. I guess I'll be goin', then," she mumbles and hurries out the door.

You smile softly to yourself as you close the door.

"Ugh," groans Cosima around a mouthful of ice cream. "I'm in heaven. Like actual heaven. Bless you for bringing me this heavenly food."

The medication has made her even more enthusiastic than usual, and that combined with the slight slur in her words makes your heart do something akin to cardiac arrest.

"Anything for you," you murmur, and you mean it. You would do absolutely anything for her. No man has ever even made you feel this way, let alone a woman. What is it that Sarah said? You'll fight for her 'til the end if you have to.

Five minutes later and Cosima's ice cream has seen better days, half-eaten and melting inside its wrapper as it sits on the table by the couch. Cosima is looking a little worse for wear herself; she is pale and sweaty, and her eyes keep drooping shut. Eventually, her chin sinks down to meet her chest, and her whole body drifts forward before she startles awake. "Whoa," she gasps, and an explosive laugh bursts from her throat followed by a few raspy coughs.

"Ma chérie," you whisper, coming forward to stroke her face. "You should rest. Let the medication do its job." You slide her glasses off her face and she lets you, suddenly very compliant and somber.

"My Cosima," you murmur, rubbing your thumb along the soft skin of her face. She avoids your gaze and your heart constricts. "What is bothering you? Please, tell me." When it comes to her, you are not above begging.

"I'm scared," she whispers, voice choked, and you recognize the way her chin starts to wobble dangerously. You react quickly, gathering her up into your arms with a swiftness and fierceness you did not know you possessed.

"Don't be, don't be. You're okay," you tell her soothingly, and the last phrase becomes a mantra. "You're okay, you're okay." The chants are punctuated by kisses placed wherever you can reach; her ear, the space just beneath her jaw, the top of her head.

"I will find a cure, Cosima," you say fiercely, squeezing her tight. "I will not let you die. I won't let you leave me when I have only just found you."

You hear a small sniffle from the face buried in your shoulder. "You promise?" comes a quiet, hoarse voice. She sounds so childlike. You smile.

"What is it you Americans say? Mark my heart?" You butcher the phrase on purpose, and when she lets out an unflattering, watery laugh you beam your success.

"Cross my heart," she corrects you softly, pulling away. You lament the loss of her body against yours and console yourself by thumbing her tears away.

You watch her press a palm to her eye and rub ferociously before deciding enough is enough. "Time to sleep, ma chérie," you inform her gently. You grab a threadbare, bright orange blanket off of a nearby chair and prompt her to lie down before covering her with it. She doesn't resist. You kneel in front of her and hold her hand as she falls asleep.

Just when you think she's drifted off, she lets out a breath and squints up at you very seriously. "I have a joke to tell you."

You chuckle. "Later, Cosima."

"It's good. If I were an enzyme, I'd be a gene so I could unzip your helicase." She furrows her brow and blinks slowly. "Wait no, that's not it-"

"Sleep," you command gently.

"I didn't tell it right."

"That's okay. I still got it. It's very clever, you cheeky monkey." She smiles, clearly proud of herself, before finally shuddering her way into unconsciousness.

Oh, yes. You will find the cure even if it kills you.