Infirmary. It's the first thing she sees when her eyes peel open, squinting through the haze of pain consuming her insides, and whatever medication has been infused into her system to dull it, to read the makeshift sign written in big, blocky letters atop the metal doorway.

What was she doing in an infirmary? How had she… oh, she'd been shot, hadn't she? Shot, in the arm with… with something that was far more powerful than the modern day bullet, something that had torn through her flesh with fire, infused her veins with agonizing jolts of electricity that felt as if they were ripping her in two. She's been shot before, back in her early days as an officer, and she could acutely remember what it had felt like.

The shot the Outsider from the alleyway had put in her bicep was nothing like that. Not even close. It was worse, so much worse. But Castle had fired back, sent the alien crumpling to its knees with a bullet between the eyes in the exit of the alley-

Kate jerks up in the bed, a cry of pain ringing out from her lips at the abrupt movement, but she needs to know if Castle is okay, if he made it back with her to wherever she is, if they both survived. She will never forgive herself if-

A gentle hand touches her left shoulder, the side of her body that hurts significantly less than the right, and travels upwards to her cheek. "Hey, Kate, hey. You're okay. I promise."

She could weep with relief at the soothing whisper of his voice. Tears are already streaking down her face as Kate forces her eyes upwards to see Castle rising from the chair beside her cot to lean over her, his gaze scanning her from head to toe in concern that shines bright blue in his eyes.

"Castle," she breathes, nothing more than a rasp, and his lips quirk ever so slightly while his thumb swipes beneath her eye, wiping away the tears that fail to cease. He looks okay from what she can see, his skin covered in dust, a nasty cut above his left eyebrow, but he's standing beside her makeshift hospital bed without issue, the panic in his gaze giving way to reverence as he holds hers. He wouldn't look nearly as well off if the aliens had won, right?

"Happened?" she manages next, wincing through a swallow, and Castle quickly reaches for a nearby table, presents her with a styrofoam cup that he positions at the seam of her lips. She hums after only a few sips of the cool water, cascading down her throat and soothing some of her discomfort, and he withdraws it for her.

"How much do you remember?" he asks, descending to sit on the edge of the cot, right next to her hip, and mm, that eases her discomfort too, having the warmth of him so close again. "Kate?"

"I - I was shot, in my arm," she mumbles, glancing down to her right. Her bicep is wrapped in thick, white gauze, an IV attached to the top of her hand, and she lifts one of her fingers, grunts at the spiral of pain that climbs the length of her arm in retaliation. "Hurts. You - you had to get the bullet out. Oh, Castle-"

"The medic says I didn't do too bad of a job. The scar won't be too pretty, but-"

"No, I'm sorry you had to do that," Kate murmurs, stretching her good arm out towards him, brushing her fingers down his forearm until they land within the embrace of his open palm.

"I'd do it again in a heartbeat," he promises her, his voice solemn, his eyes glittering in the fluorescent lighting. "I had to get it out of you, Kate. It would have killed you."

"A bullet to the arm?" she questions, her brow creasing with confusion, but Castle shakes his head.

"No, this was an - an alien bullet. As in, the second it penetrated your skin, settled in your flesh, it released electric shocks into your system, pulsating outwards from the entry wound. Kills within minutes," he explains, dropping his gaze to her injured arm. "If we had waited any longer to remove it or if the bullet would have hit anywhere near your chest, you wouldn't have made it."

His eyes fail to rise again, imagined grief springing to life in his gaze, the possibilities of what could have been playing out in front of him, and Kate tugs on his fingers, jerks his attention back to her face.

"We stayed in the alley until Esposito and the medic Ryan sent came to get you. The worst of it was already over, the Outsiders almost completely eradicated, so we made it back to the plane, treated you in the air," he explains, his thumb circling one of her knuckles, swiveling round and round. "We're still in the plane now. Flying over Rochester with some Clorox. We're going to need a lot of chemicals to rid the earth of these things, but we're making good progress."

"It's over?" she questions, trapping his thumb with her own, forcing it to still.

Castle nods, relief but so much exhaustions branching out to fill the lines that spread from the corners of his eyes.

"We haven't destroyed them all, but we will. We're in full communication with all remaining surviving sectors and the assholes don't stand a chance anymore," he promises her, his lips quirking in the corners and feeding the slow bloom of hope through her system, combatting the sharp throb of pain.

"Where's Alexis?" she murmurs, scanning the room for the familiar flare of bright red hair, but coming up empty. Immediate worry begins to churn through her gut, but Castle squeezes her hand.

"She's completely fine. She was here with me from the second we were picked up, but they've brought in other wounded survivors since and she's been adamant about helping in any way possible," he explains on a sigh and Kate hums, the smile struggling to form on her lips.

"Good kid."

"The best. She decided that if college is ever a thing again, she wants to attend medical school," Castle informs her and a soft chuckle climbs her throat to fill the air.

"You think it will ever come close?" she mumbles, gripping his hand to stay present, refusing to drift back into unconsciousness when so much is still happening, when Castle is sitting all alone beside her. "To being what it was again?"

Rick cradles her hand in both of his, one of his thumbs tracing an infinity symbol along her knuckles, and Kate curls her fingers, twines them with a set of his.

"I don't know," he responds with honesty, but his eyes are hopeful when she lifts her gaze back to him, beautiful pools of cerulean that drench her in reassurance. "All I know for certain is that I have you, my daughter, and regardless of what happens next, you two are all I need."

Kate hums and tugs on his hand, yearns for the warmth of his body alongside hers. She ignores his protests, his qualms about accidentally hurting her, and within seconds, he huffs his defeat.

"It's just my right side, lie on my left," she instructs, fighting to control her expression when his careful movements jostle the cheap cot, rattle the damaged side of her body and give life to the dulled waves of pain lapping at the surface of her skin.

The front of his body seals against her side, infuses her with a sweet warmth that quiets the riot of agony through her veins, brings peace to her bones.

"Okay?" he asks, resting their intertwined hands to her stomach, and Kate hums her assent, too afraid to face the repercussions of nodding in answer.

"You said - said that after this was over, we'd have the life we should have," she reminds him, peeling her eyes back open and gingerly turning her head to see his face pillowed by his folded arm, close enough for her to touch the tip of her nose to his in a kiss with the simple tilt of her chin.

"I did," he agrees with a grin, lifting his free hand to her cheek, tucking an oily strand of hair behind her ear. "And we will."

"Already do," Kate whispers, craning her neck to smear a kiss to the inside of his wrist before she can disappear.

Castle wanders down the hallway of the bunker, stops in front of his daughter's bedroom door, and pauses with his fist half raised to the door at the familiar grunt of pain he can hear from the other side. He eases the door open instead, finds the sight he had expected, and cringes at the string of curses that fly from Kate's mouth.

"You owe me like six gummy bears for that sentence alone," Alexis points out, her lips twisted in a smile that she tries to subdue for Beckett's sake, but Kate releases a breathless exhale of laughter.

"I'll owe you an entire jar after this session," she mutters, pursing her lips as his daughter extends Kate's arm higher, testing her range of motion, and carefully lowering the limb back to Beckett's side when she releases a muffled cry into her own shoulder.

"You did better today," Alexis praises, offering Kate the sling, but she refuses, cradling her arm to her side and taking a moment to breathe, her eyes screwed shut in concentration.

"Harsh physical therapy session?" Castle inquires gently, closing the door behind him and stepping deeper into the room.

It's been two weeks since the final battle against the Outsiders, since humanity had finally been given the chance to fight back. And they had won, but they were still living in the underground bunker by choice. Living above ground still provided an unshakable anxiety for most despite the eradication of the alien species that had invaded the planet only a few months ago, what felt like another lifetime, and rebuilding the world would take years. They could spare a few extra weeks, months even, in the safety of a massive bunker built to survive an apocalypse.

Especially while Kate was working through the worst of her recovery.

"Harsh would be putting it lightly," Kate breathes, her lips twitching with her best attempt at a smile for him before she stands from his daughter's bed.

The damage from the electric bullet to her arm had been extensive, severe, and permanent in certain places. She had nerve damage, burned internal tissue, and a shredded bicep muscle with a still healing bullet wound and a high risk of atrophy. Her injury forced her to remain on the sidelines, held back from heading out with the teams who left each morning, venturing to hunt down the last of the Outsiders, and the frustration of that sometimes drove her crazy.

"I told Ryan to bring back some resistance bands if they can stop by an abandoned gym or fitness store on the way home," Alexis quips, and Castle nearly chokes on a laugh at the glowering look Kate shoots his daughter. "Hey, it's good for you and we need as much equipment as we can get. We're under stocked here."

"You're lucky I love you, Alexis," Kate grumbles, using her good hand to tug on the end of his daughter's French braid as she snags her sling from the edge of Alexis's bed on her way to the door.

"I'll see you guys in an hour for dinner," Alexis grins, plopping onto her bed and retrieving her textbook from the top of her nightstand, settling in with the Essentials of Physical Medication and Rehabilitation open on her lap.

Ryan and Esposito had been scavenging for Alexis each time they left base, returning with college textbooks and medical supplies on top of the usual essentials of food, weapons, and toiletries. Esposito, in particular, had been going out of his way to find everything Alexis asked for, even raiding his former girlfriend's morgue earlier in the week. Apparently, the woman, Lanie, had been an ME before all of this and Alexis's newfound passion for medicine and healing brought out a reminiscent fondness in the soldier with a heart of steel.

"Don't study too hard, Pumpkin," Castle teases, placing a gentle hand to the small of Kate's back, walking across the hall with her to the open bedroom door of their room.

Alexis had sought out her own room only a couple of days after they had returned, politely stating that she had needed her own space to study, store all of her new books, and insisting that she would be fine right across the hall. And if she ever wasn't, their room still had an extra bed for her to return to if ever she needed it.

Castle closes the door and eases the sling from Kate's stiff fingers, carefully aids her in adjusting her right arm into the black sling that rests across her chest, holds her arm in place against her ribcage.

Kate doesn't like to be coddled, doesn't like to show weakness either, especially not in front of his daughter. Now, though, in the privacy of their room, she lists into his side, presses her face to his neck and releases a shuddering breath into his skin. Rick sighs and bands his arm around her waist, cradles her body against his chest and dusts his lips along her hairline.

"I know I should be grateful we survived and that the damage could be worse, but this sucks," she mumbles, attempting to lighten the mood, but she's miserable, and he hates it.

"I know," he murmurs, running his knuckles up and down the length of her spine. "I know, but you're making progress, day by day, and soon you'll be using your arm like normal again."

"Rick," she sighs, because they both know that's nothing more than wishful thinking. The doctor that had treated her on the plane, one of the only two professionals they had, had informed her with a solemn expression that she could build back her strength, regain mobility and movement, but her arm would never be back to its former state. It wasn't life threatening, could have been worse, just as she had said, but it would leave her slightly handicapped, and that eats at her.

"Fine, about seventy-five percent back to normal," he concedes, lowering his head to smear a kiss to the corner of her eye. "But I don't think for a second that you're going to let this hinder you."

"You have too much faith in me," she sighs, but Castle shakes his head.

"I have the amount you've proven is worth investing, which is a lot," he states, earning a huff of her laughter against his throat. "In a matter of months, weeks maybe, you won't need the sling, the therapy, and it won't be the same, but you'll still work, still be okay. Just like the world."

Kate tangles her fingers in the back of his shirt, but nods her head, releases a quiet breath against his jaw. "In the meantime?"

"You'll heal, the world will too, and once some structure has returned to the earth, you and I are going to find a place to live with my daughter until she decides she wants to be further than across the hall," he states on a sigh, already seeing the streak of independence running bright and clear through his brave little girl turned young woman. He'll never let her go far, couldn't bear it after everything they've been through together, but he will have to let her go nonetheless.

Kate touches her lips to the hinge of his jaw, a kiss of comfort, and he squeezes her hip in appreciation, continues on with his thoughts, his hopes for them.

"We'll develop a new normal. I don't know what that'll look like when the majority of the population is gone and the entire planet is a mess, but we're made to adapt, so I know we will."

She hums her agreement, straightens a little against his side, but remains silent, awaits the rest of his predictions with steady breath and the brush of her lashes along his skin.

"Traditions died with everything else, but I'm going to marry you. Soon."

The noise that slips past her lips is a toss up between a startled laugh and a scoff, but her nose nuzzles his cheek in what he knows is approval.

"I doubt I can get you the ring you deserve, but-"

"Rick," she sighs in gentle reprimand. "I don't need a ring."

"Still want to get you one," he murmurs, pulling back just enough to see her face, to meet the eyes staring up at him, tender and alight with affection, hints of amusement at his insistence to do this right. "I'll tell the boys to raid a Tiffany's next week, bring back a catalogue or two-"

"Castle," she groans, shaking her head, but her cheeks are warm, her smile wide at his throat, and he chuckles, stains another kiss to her forehead.

"We don't have to do a wedding, but we could still do something small. You, me, and Alexis, the boys if you'd like," he muses, swaying them a little, the imagery beginning to cloud his vision. "I want to have vows to read to you, I want to slip a ring onto your finger, call you my wife-"

Kate draws back to arch on the toes of her boots, smudge her lips to his in a kiss that bruises, claims, and he hums, flattens his palm at the base of her spine to refrain from deepening it, from succumbing to the stroke of her tongue or the suck of his bottom lip into the heat of her mouth. He wants to, oh he wants to, but her arm is still so very fragile-

"I hate this," she growls, nipping at the corner of his mouth when he huffs a laugh at her. "One time, Castle. We had one time together and I feel so cheated."

"You're telling me," he mutters, trailing his hand up her vertebrae and cradling the back of her skull in the splay of his fingers. "Do you know how furious I would have been if we would have died without being able to do that again? Would have been even more unfair."

"The second I'm better-"

"We're making up for so much time, Kate Beckett," he murmurs, gentling her with a brush of his lips. "And then, after that, we can start repopulating the earth."

"Castle," she chokes out and his laughter is loud this time, echoing off the walls of the tiny room, and Kate uses her good arm to smack his shoulder. "That is not happening."

"Yet."

"Shut up," she groans, burrowing her face in his neck again. "Not anytime soon."

"No," he agrees softly, propping his chin atop her head. "We have all the time in the world to decide if or when. Our future can be whatever we want it to be now."

Kate sighs, placated enough by his words to allow her body to relax against him, forgetting his jokes about repopulation that always manage to rattle her, and rests her cheek to his collarbone, hooks her thumb in his belt loop.

"It's like you said," she murmurs, her lips moving against the thrum of his pulse. "As long as this world lets me have you and my physical therapist over there…"

Castle chuckles, but his heartbeat is accelerating. He knows she loves him, loves his daughter and this little family they've created at the end of the world, but it still has his heart exalting every time she continues to choose them, him, every time she vocalizes her certainty in the decision. This new world didn't require them to be together, but with each word he grew more secure in the truth.

"As long as I'm allowed to have this," Kate whispers. "I have everything I need."

A/N: Thank you to Alex for the help with the title, to Nadia for the always amazing cover art, and to everyone who took the time to give this story a chance. Your reviews, tweets, messages, and all other forms of feedback have been incredible and I hope it's been an enjoyable adventure.