It's a side effect of being an 084, Jemma concludes.
Her resting heart rate is normal; her blood pressure is normal. Everything Jemma can measure in the lab is normal, yet Skye is never going to age.
There's a beat of silence after Jemma delivers this news, and her eyes lay downcast and unwilling to meet Skye's own questioning gaze. Coulson nods, pats Skye's shoulder, and leaves. She's thankful for that, at least.
"It appears as though you'll stop aging in five or so years," Jemma finally says, more to break the silence than anything. She still doesn't look up. "I don't- I don't know… I-"
She's not sure where the tears came from, but suddenly they're clouding her eyes and tightening her throat. Skye breathes in sharply and slides off the examination table, stepping over to Jemma and wrapping her arms around the other girl tightly.
"I don't know what to do," Jemma admits. "You're not going to age." And though she doesn't say it, Skye can hear the "and I will" that follows.
"I don't know either," Skye murmurs. "I have no idea."
It's easy for Skye to push it from her mind.
It's her whole life philosophy, really: don't fret if you don't have to. She's done anger and anguish and the whole spectrum of bad emotions, and she consciously pushes those feelings aside. Skye continues living normally, because she's not sure what else to do.
And each night she lays in bed with Jemma, arms curling around the girl's stomach and fingers tracing patterns on her skin. It's easy to forget, especially here and now.
Jemma passes Fitz the vial of fluid, and her eyes catch on its deep green shine. It's the same color as the GH-325 had been, and she finds herself sighing before she can stop herself.
Fitz quirks his eyebrow. "How've you been?" he asks quietly. "With the news about Skye and all."
Jemma turns away, pretending not to hear and knowing all the while that it's a futile effort.
"Simmons," he repeats.
"I don't know, Fitz," she finally speaks. "She's got maybe five more years of normal aging, and then what?"
He pauses, taking the time to walk over to her and placing his hand on her shoulder. "So you plan on staying with her." It's not question; he knows the answer.
"I can't imagine doing anything else."
The thermometer Jemma's holding slips from her grasp, and it falls to the floor with a clatter. Fitz shakes his head. They don't go to clean it up.
"And she hasn't said anything?" he offers. "About this, about your relationship?"
It's Jemma's turn to shake her head, and she follows it with a quiet "not really."
"I think she wants to stay too. I think she's scared, Simmons. She's probably terrified, and she doesn't want you to be scared."
"I am, though. Scared. I'm scared."
"I know." He lets his hand fall from her arm, and he embraces her instead. "But you two are strong. You'll make it work."
Jemma doesn't reply, but she hopes Fitz is right.
"How are you so nonchalant about this?" Jemma demands, brow furrowed and gaze angry.
Skye looks apologetic, at least — Jemma's grateful for that — and she holds the cellphone like it's toxic. The song is still playing, and the words "forever young" repeat over and over and echo about the room. It had been an attempt at a joke, but now she fears that any movement to stop it will result in an increase in Jemma's wrath. She's frozen.
"I'm not, I-" Skye starts, but Jemma cuts her off.
"You're going to be in your twenties forever, Skye. You're going to look twenty-five, maybe twenty-six, when I'm eighty. How are you okay with that?"
"I'm not okay with it, Jem, but I don't have a choice. What else am I supposed to-"
"I love you, Skye, and I can't imagine leaving, but I- I… I don't know how to stay."
The song stops then, and the silence is almost deafening. Skye stands from her seat on the table and goes to step past Jemma. She knows she should've brought it up sooner, had this discussion before tensions heightened, but she couldn't bring herself to. It was easy to seem nonchalant, yet inside Skye was panicking.
"You're right," Skye whispers coldly. "Yeah. I'm going to be twenty-something forever, and the only problem with that is that you think it's awkward. God, Jemma, I love you so much, but I-" Skye's hand goes out to desperately, quickly grab Jemma's, and the warmth of her touch sends a shiver down her spine. "I'm going to go."
Skye walks away before either of them has a chance to say another word.
Jemma spins, her mouth opening in shock and her hand reaching out to chase the air where Skye had been. It's empty now, though. A moment earlier the space had been filled with Skye. Smart, funny, solid Skye, and now it's air.
They don't talk for days, and the days become weeks, but neither of them can bring themselves to go speak to the other.
"You look dead, rookie," Jemma hears Ward say.
"Haven't been sleeping well," Skye replies. Jemma can't see her from around the corner, but she can picture Skye's face: the bags under her eyes are deepened, and she's likely biting her lower lip like she always does when she's tired. She'd be tapping her foot rapidly, because that's what Skye does to keep herself awake.
He pauses. "Go talk to her, Skye."
"She's fully capable of talking to me."
Before Jemma has a chance to move, Skye is walking out of the room and straight toward her. There's a flash of recognition as she realizes Jemma's been listening, but she doesn't stop.
Ward follows soon after. "You two are crazy."
She agrees.
It's almost midnight when Skye knocks on Jemma's bunk. It's been sixteen days since their argument — she can't help but count them — and in her hand Skye hold sixteen pieces of licorice.
"Wh- What are you doing here?"
Skye shrugs. "I was going to bring you flowers, but it turns out that flowers are hard to find when you live on an airplane. Who knew, right?" She breathes out a nervous laugh, thrusting the licorice forward. "I'm an idiot. And I hope you like Twizzlers."
There's a moment of silence that feels ten times longer, and just as Skye goes to leave Jemma steps forward. She forgoes the licorice, kissing Skye instead. Her hands tangle in the girl's hair, and she grins against Skye's chapstick flavored lips.
Skye stands somewhat uselessly, hands dangling at her sides and eyes closed peacefully, but she responds eagerly to the touch of Jemma's lips. After a minute she breaks away, raising her free hand in a question.
Jemma shakes her head, and Skye's eyes flash with panic. She grins, though, and lets her hand trace the line of Skye's collarbone.
"You weren't the only idiot. I've missed you."
Skye ducks her head and grins sillily. "Good. I've missed you too." She tosses the licorice sticks onto the desk next to her, taking full advantage of having both hands free.
Her fingers ghost along the skin under the hem of Jemma's shirt, and she laughs. "So are you going to close your bunk door or…"
Jemma reaches back, flicking the button and letting the door slide shut. "There."
And that's that.
They live normal lives and try their hardest to forget about the foreign blood coursing through Skye's veins. It's hard, certainly, but somehow they manage. They talk about it regularly, talk about what life will be like in a hundred years when Skye's still young. They do everything possible to learn more about her condition, yet test after test comes back without results.
The team eventually gets disbanded, and Skye and Jemma move together to Washington, DC. Jemma begins to age, finding her first gray hair with a frown.
Skye twirls it around her finger with a shy smile, and she leans forward to kiss Jemma's temple softly.
They celebrate Skye's birthday somewhat ironically, for neither of them can be truly sure what it means anymore. It's still her birthday — that much is obvious — but it's become a symbol of another year instead of a symbol of a new age.
Skye makes a joke about how "age is just a number" every once and a while, and Jemma rolls her eyes each time.
Jemma is eighty three years old when she dies.
It's a different world, and Skye has embraced it fully. But then the world comes crashing down.
They had said it was painless, but Skye doesn't know what that means. She can picture Jemma scoffing at the idea, saying that an instant would feel rather long when it's an instant of blinding pain, but she avoids that thought. Skye doesn't want to carry Jemma's pain because her own is more than she can bear.
She arrives at the service with burning eyes and a raw throat, and the man steps forward.
"Are you Jemma Simmons's daughter?"
The statement makes it all the more terrible, and she steps away without replying, walks slowly toward the stone etched with Jemma's name, the date of her birth, and now the date of her death. She kneels.
Skye had always thought that honor was silly, that breaking someone's heart to keep them safe was selfish, yet a part of her wishes she had left before this pain had come, this crushing, hopeless pain.
But she knows she couldn't have. She knows that those years with Jemma were worth this pain.
There's not much she can say that she hasn't said at some point already, and the man still stands behind her. Skye reaches into her pocket and pulls out sixteen pieces of licorice and sets them on the grave.
"I love you."