A/N: Rewatching one of my favorite episodes brought this AU scenario - that got a bit out of hand - to mind.

Picks up from the interrogation with Vulcan Simmons in 3x13, Knockdown. Only this time, it isn't Beckett who loses her temper.

She had noticed the anger ripple up his spine with a ferocity she had felt from her chair beside him at the mention of her "giving it up" in the backseat of a car, heard it lying below the reprimand Castle shot across the table at Vulcan Simmons, but he isn't the one on the brink of losing control here. With every word the behemoth of a man in front of them speaks, the deeper the fractures to her already cracking restraint become.

"He's sweet on you," Vulcan observes, appraising Castle with a wicked sense of amusement. "Makes him brave."

"What was your association with Detective John Raglan?" Beckett demands, steering the conversation back onto the path it needs to be taking, away from Castle and the growing irritation now leaking onto the stony expression of her partner's face.

Vulcan toys with her, dismisses her mention of Raglan with a few halfhearted musings of the man, and begins dissecting her interrogation methods instead.

"During this phase of the interrogation, the interrogator may invade the suspect's personal space in order to increase his discomfort. You wanna invade my personal space?" he turns the question towards Castle, and it isn't any secret how tempted he is, but it does surprise her, just a little, to witness Castle's body so rigid, coiling in preparation to attack.

He wouldn't, though. Not Castle, such a gentle man... would he?

"Look. At. Me," Beckett instructs before she can find out, bringing her mother into the interrogation next, walking Simmons through the murder of Johanna Beckett and her two colleagues "through the eyes of a suspect", as he observes, and gritting her teeth in an attempt not to bristle as Vulcan listens with a hint of a smirk curling the corner of his mouth, dancing in the dark shadows of his eyes. "Look at her face," she insists, sliding the crime scene photo of her mother dead and bloodied in an alley. "Tell me you don't remember her."

"You know, Detective Beckett," Simmons begins, barely glancing at the photo but sitting forward in his chair for the first time since he was seated, and she tries to brace herself for whatever is about to leave this man's mouth, because she can already tell from the sinister tone of his voice that it could unhinge her. "I think I do remember her. Bled out in an alley like the trash she was," he smiles, the grin malicious and spreading wide across his lips, causing her heart to thrash with rage in her chest.

"Mr. Simmons, you better watch it-"

"Rich bitch from uptown on safari in the heights. Somebody should have warned her not to feed or tease the animals."

Her lungs are tight, her breathing shallow as her fingers tremble atop the table. "You-"

"If she had, she might not have gotten eaten," he states, as if it's a lesson, that wicked smile returning with the flint of mischief in his black eyes as he rises from the table. "From what I hear though, she was pretty tasty."

Kate jerks up from her seat, ready to do damage, to make Vulcan Simmons pay, but before she can even dig her hands into his shirt and fling him against the wall, Castle already has him by the neck.

For the split second it takes for him to shove Vulcan Simmons into the two way mirror, she's frozen, speechless as the glass shatters and the muscles flex in Castle's back as he strangles their suspect.

"Castle!" she shouts, lurching forward to catch him by the shoulders, but it's as if he doesn't hear her, doesn't flinch at the curl of her fingers into the plaid flannel of his shirt. "Castle, stop-"

"I'll make you regret every word," she hears him growl, his voice feral and snarling, almost unrecognizable.

"Just try," Vulcan gets out, his lips still in that conniving smirk even as the encompassing fists of Castle's hands cut off his airway.

"Rick," she snaps, her nails snagging in his shirt, piercing into the skin beneath, but it isn't until the doors burst open and Ryan and Esposito are charging in, commanding for him to stand down and aiding her in prying him off of Simmons.

The raging storm clouds of his eyes remain sharp and trained on their suspect though, all too ready to dive back into battle, and for the first time since she met him nearly three years ago, she sees the threat Richard Castle can pose with the power of his bare hands.

"Castle, that's enough," Ryan warns, creating a blockade between the two men with Esposito, restraining Simmons by the arms even though the bastard merely smirks back at them, pleased with himself.

"Remember your old life, Simmons," Beckett growls over Esposito's shoulder that attempts to nudge her away. "Savor it. Because I'm gonna take it all away," she swears through her teeth, turning her back on him before she can see the maniacal grin accompanying the villainous laughter and placing both of her hands on Castle's chest.

Finally, his eyes jerk down to her face, to the palms splayed wide on his chest while she pushes him out of the interrogation room.

"Sure you don't want some more?" Vulcan calls and that deadly calm spread across Castle's face wavers, flashes with the thunderous rage that had been ignited only moments ago, set flame to his temper.

"That's enough," Esposito snaps, shoving Vulcan back against the broken mirror and glaring at Beckett, reminding her to get Castle the hell away from him.

"Castle, hey," she murmurs, backing him further away from the open doorway, steering him towards her desk with her hands still pressed against his sternum. "You with me?"

He tears his eyes away from the ruins of the interrogation room, trains them on her, and she watches in silent fascination as the vicious storm clouds fade, a dull but calming shade of blue engulfing his irises, smoothing the harsh lines and sharp angles of his face.

"Of course," he mumbles, swallowing hard, blinking a couple of times before he lifts a hand to rub at his eyes. "With you. Of course."

"What the hell were you thinking?" she hisses then, her fingers fisting in the fabric of his shirt. "You could have-"

"I'm sorry, I - I didn't mean to. I swear I didn't mean to ruin the interrogation," he stammers, staring down at her so forlorn and apologetic, and it breaks her heart without warning and quite brutally to learn he thinks that was her only concern.

"Castle, it isn't just-"

"Beckett." Montgomery's command of her name rings out across the bullpen. "In my office. Now."

"Shit," she sighs, scraping a hand through her hair, but catching Castle with the fingers still snagged in his shirt when he starts towards her captain's office. "What are you doing now?"

"Beckett, what happened in there was my fault. I have to-"

"Stay here," she finishes for him, clapping a hand atop his shoulder and pressing down until his knees bend and he collapses into his usual seat beside her desk. "You have to stay here until I come back, got it?"

He purses his lips, but leans back in his seat, unhappy with her instruction, but listening. Kate takes a deep breath and spins on her heel, strides towards Montgomery with a confidence that she doesn't feel, that is quickly being eaten alive with dread.

Castle can hear Montgomery yelling at her from his office all the way across the bullpen and has to continue replaying her words in his head, looping her order to stay here over and over again. He owes it to her, after the stunt he just pulled with Simmons, owes it to her to listen, to be good. Be the partner she deserves.

But his heart stops cold at the unmistakable verdict of Montgomery's next words.

"You're off this case."

Silence. Horrible, breath holding silence, until she stammers out an argument, fighting with her superior until he raises his voice loud enough for the entire homicide floor to catch an earful.

And then she's storming out, striding towards her desk with fury and tears in her eyes.

"Castle, let's go," she demands, snatching her jacket from the back of her chair, and he doesn't think twice, jolting up from his seat and hurrying to catch up with her on her charge to the elevator.

"What happened?" he asks the second their both in the lift, the doors sliding shut on the curious faces of fellow officers and detectives who had surely heard the whole thing already.

"We're off the case," she whispers, her jaw set harsh and cutting as she blinks against the moisture crowding her eyes.

"No," he protests, reaching out to press the emergency stop button and redirect their descent upwards. "He can't do that just because I-"

"It wasn't all you," Beckett sighs, blocking the panel of buttons with her hand. "I let Simmons play me, get under my skin, and after what he said... I was only a second behind you, Castle."

Rick's brow furrows. "What do you mean?"

"If you hadn't gotten to Simmons first, I would have had him up against that mirror. You just beat me to it," she explains, stepping out into the lobby once the elevator doors shift open.

"But I didn't even notice you get up," Castle argues, walking briskly alongside her through the lobby, out into the bitter January air.

"I don't think you noticed much of anything in that moment," Kate points out, unlocking the Crown Vic with a shuddering breath. She hasn't even put her coat on yet, her bare arms exposed to the frigid chill, and so he slides in to her cruiser quickly, prompts her to do the same.

"No," he concedes, though, because she's right. The moment Vulcan Simmons began toeing the line of inappropriate with her, the moment he spoke ill of her mother, poured salt into the raw wound Kate had inadvertently exposed to the man, Castle had lost his grip on the reins of his control. And then he had only seen red. "I guess I didn't."

They make the drive to her apartment in silence, not awkward but a contemplative, heavy and accepting form of quiet. He doesn't ask where they're going, relieved when he doesn't recognize the route and is assured that she isn't taking him home. Beckett puts the car in park in front of an apartment building in Tribeca, turns off the engine and exits the vehicle without a word.

The withdrawal of her keys from her coat pocket as they encounter the sidewalk deems his guess correct. They've come to her home instead.

"Josh," he blurts after they're already in the elevator, headed to the third floor, and Kate turns her eyes to him with her brow creased in question. "He isn't... here, is he?"

"No, he's in Africa," Beckett informs him, not exactly sounding disappointed. "Saving the world."

They step off the elevator in sync, walk the short distance to her front door, and she guides him inside, gives him a moment to marvel over her new place, to feel grateful she's allowed him the privilege of being here with her after what he's done.

"I'm sorry. Again," he states while Beckett drifts into her kitchen. She pauses at the stove, the deep breath causing her ribs to expand beneath the thin fabric of her shirt.

"I didn't think you had that side to you," she comments, glancing back to him with bloodshot hazel eyes that have softened just a fraction for him. "I didn't know you could..."

Her sentence trails, but he doesn't press her for the rest.

"When it comes to the people I lo-" Oh, careful. He needs to be so careful. But if the subtle flare of her pupils is any indication, he may have already shown her his cards. "When it comes to people I care about, I do."

She nods, doesn't call him out on the correction, but her demeanor has changed, tightened up with defense.

"I'm not angry with you," she murmurs and he's almost surprised by the weight that dissolves from his chest at the reassurance he hadn't even known he needed. "And I don't want you to be sorry either. If anyone should be sorry here, it's me."

His feet jerk him from the foyer at that, carrying him into the kitchen and standing just inches away from her tense frame. "What are you talking about? You didn't-"

"I dragged you into this, all of it," she whispers, chewing hard on her bottom lip, on the verge of drawing blood. "And I just keep dragging you down with me-"

"Kate, I chose this," he growls, his chest nearly brushing her shoulder and he knows he needs to step back, that he's crossed enough boundaries for one day, but she isn't moving away and the warmth of her, the scent of cherries and reassurance is too good to abandon. "I'm like... your plucky sidekick," he adds, just to see the pitiful quirk of her lips, even if the attempt at a smile falls away a mere second later.

"You're more than that, I think," she rasps, ducking her head to hide her face behind the waves of her hair.

"Partner then," he decides. "Partners have each other's backs like we do, head into danger together, fight crime and-"

"Shove the bad guys into mirrors like an over protective bully?" she hums, arching an eyebrow at him, but the sad little curl to the corner of her mouth is back and accompanying the question.

"Sometimes," he shrugs. "I can't just stand by and let someone hurt you, not even with words, and I know - I know it isn't my job to protect you, or that you even need protecting, but I just - I care about you."

He may even love her, but 'caring' will do for now.

"And I'm sorry if that-"

"Castle," she huffs, pushing off from the edge of the stovetop and drifting towards him, hooking an arm around his neck and curling the other against his chest, over his heart.

He tries not to look too closely into what that could mean. Tries not to let his breath catch too harshly in his lungs at the closeness of her either, at the feel of Kate Beckett hugging him.

"Don't apologize. Not for that." When she fails to move away, remaining pressed against him, Castle laces gentle arms around her waist, embraces her like he's always wanted to and listens to her sigh, as if in content with her chin propped atop his shoulder. "Never apologize for caring about me."

She stays in Castle's arms for longer than she should, longer than what is appropriate for two strictly platonic friends, or partners, as he's now deemed them, but he's warm and feels like safety and it's everything she needs after the splintering ache this case has embedded in her chest.

"Good." The low rumble of his voice breaks the comforting cocoon of soothing silence that had come with his embrace. "Because I can't be truly sorry. Don't really want to be."

The image of his face from the day before, stained with horror, the phantom brush of his fingertips at her side as he eased her jacket out of the way to check for a bullet that wasn't meant for her - it all flashes in her mind, has her gripping him a little tighter. This case has always enabled her with blinders, blurred her vision to anything and anyone else, but this time... this time Rick Castle brings her clarity. Has her thinking about something other than justice for a change, even if only for a single afternoon.

"Vulcan Simmons was right," she murmurs, burying her fingers in the fine hairs at the base of his skull when he stiffens, drawing back just enough to see the perplexed expression clouding his features. "About your bravery, Castle."

"Because I'm sweet on you?" he volleys back, his eyebrows hitching with question, and it's enough to pull a strangled laugh from her throat.

"Not what I was going for, but-"

The buzz of her phone from the back pocket of her jeans has them both jerking apart, the reminder of a reality in which they don't touch, don't embrace and acknowledge how 'sweet on her' he may be.

"Answer it," Castle encourages. "Could be Montgomery coming to his senses and realizing he needs his best detective back on this case as soon as possible."

Beckett offers him a halfhearted smile for that, but it quickly dissipates from her lips at the familiar flash of Josh's picture on her screen.

"Or your world saving boyfriend," Castle murmurs the correction, but when she lifts her eyes back to him, he's doing his best to retain that supportive gleam in his gaze, trying so hard not to look crestfallen.

It rips her heart straight from her chest.

"Castle," she sighs, but he shakes his head, nods towards the phone.

"I can wait, I don't mind. If you want me to stick around, that is-"

"Yes, stay here," she repeats the command from earlier, softer this time, a request. Because she'll make it worth it if he stays. She can be brave too.

His treacherous heart sinks in his chest, snagging along the walls of his ribcage on the way down and gaining a few new scrapes and puncture wounds as Kate disappears down a short hallway, towards what he assumes is her bedroom with the phone pressed to her ear and her boyfriend on the other line.

He doesn't know what he had expected when she brought him here, when she had let him hold her in the middle of her kitchen, but it hadn't involved her boyfriend, that much he was sure of.

Rick flexes his fingers, the lack of her presence to distract him causing the dull flares of tension in his digits to unfurl. His grip on Simmons's neck had been too tight, brutal enough to cramp his bones, and it scared him a little, how much damage he had been ready to inflict upon another human being with his bare hands.

He ventures towards the kitchen sink, adjusts the faucets until warm water rushes onto his fingers, soothes the stiff joints. The water flows and trickles over the small pile of dishes filling the deep basin of the sink below and he knows it's not his home, that cleaning her dishes for her would likely be some weird invasion of privacy, but he's alone in her kitchen and it can't hurt, can it?

Castle plucks the dish soap from the head of the sink, pours a dollop into the rising water in the sink and infuses the nearby sponge with another squirt of the purple liquid soap that smells like lavender and spring.

He's scrubbed through the entire pile of plates and coffee mugs by the time he hears a door opening.

Kate returns from her bedroom with her phone pressed facedown against her thigh and her brow in a deep contemplative crease, but she pauses in the middle of her living room at the sight of him.

"How's Josh?" he inquires, drying his hands on the nearest dishtowel.

"You're doing my dishes?" she replies instead, her head tilting to the side in a mixture of question and amusement.

"I… got bored?" He shrugs, but Kate only shakes her head, a quiet chuckle on her lips as she resumes her walk towards him.

"Josh is great," she finally responds. "He loves it there, loves his work."

"That's always good," Castle murmurs, trying his best not to let it become awkward. They've never really talked about the other man much and he's never minded the lack of knowledge. He already knew enough to irrationally hate the world saving heart surgeon who rode in to pick her up at work on his motorcycle.

"You know, Castle, it's funny," she muses on a sigh, joining him in the kitchen, taking the dishrag from his hands with a smile that is more sorrowful than anything. "At first I loved that he was so busy. It's given me an opportunity to keep one foot out the door just in case."

"But with one foot out the door, it's hard to know where you stand," he challenges carefully and Beckett nods her assent, shuffles the toe of her boot against the hardwood of the floor.

"And even if I did, I mean, what does it mean? He's out there. He's saving people. And I can't compete with that."

He wants to tell her that with him, she would have nothing to compete with. Sure, he has his writing and he loves it, but Kate Beckett would always come first, only ever rivaled by his family that he already considers her a part of.

But he's not as brave as she believes him to be, so he takes the easy way out, goes along with the path of their conversation about another man. One he can't even compare to.

"No one can."

"And that's one of the things that attracted me to him the most. That passion, that drive. Why is it that the thing that attracts you to a person always ends up being that thing that just drives you crazy?" Hearing how crazy she is about Josh has him glancing towards the door, his heart twisting, tangling with his lungs as it beats too hard against his ribs, making each breath painful. "I've just been wishing… I wish that I had someone who would be there for me, and I could be there for him, and we could just dive in to it together."

She could, he wants to tell her, she could have that. Have that with him. He would dive into the deep end with her in a heartbeat.

"And I'll never have that with Josh, which is why I just broke up with him."

It's almost painful how quickly his eyes snap back to her, searching every inch of her face for a lie or misunderstanding, attempting to prove to himself that he did not just imagine those words.

"You - you broke up?"

"It wasn't exactly how I'd hoped to do it, over the phone like that," she admits, her eyes downcast before returning to him with something fierce and beautiful shimmering gold in her irises. "But I feel like... like my relationship with Josh turned into a hiding place after awhile. Maybe that's what it had been from the start."

His chest expands in silent relief at the conclusion she's come to all on her own, a theory he's harbored since she began dating Demming but never dared to state aloud, how she hid in nowhere relationships with men she didn't love, just as he sometimes suspected she hid in her mother's case.

"I don't want to be a coward."

"Beckett," he swears her name like a curse, abandoning the clean dishes to come for her, stopping only a breath away from touching her. "A coward is the last thing you are, could ever be, do you understand that?"

"Castle," she sighs, as if she's ready to dispute his statement, so he lifts his hands to her shoulders, cradles the rounded bones in his palms, ensuring that she can feel how serious he is.

"We all get scared sometimes, we're all afraid of things," he murmurs, tracing the hard lines of bones beneath his fingers, his thumbs scaling the edges of her collarbones. "That isn't cowardice, it's part of being human."

A gentle smile flirts with the corners of her mouth. "That may be true, but there are certain things in my life that I don't want to be afraid of anymore."

"Like what?" he prompts, expecting something about her mother's case, about her career or even how she approaches relationships, but her response is far from what he had anticipated.

Kate's fingers rise to his chin, her palm sliding to cup his jaw and her thumb extending to graze the seam of his lips, burning the flesh of his mouth with the sear of electricity her touch elicits.

"This?" she breathes, raising hopeful eyebrows at him, and oh, oh his heart is on one hell of a roller coaster today. "How you feel about me... it may make you brave, according to Simmons, but you do the same for me, Rick," she confesses on a breath that quakes on its way past her lips. "You make me brave."

"You were brave, always brave, long before you met me," he points out, because she has to know that, has to know that she has always been nothing short of a warrior, certainly not a coward, not ever.

"Braver, then," she hums, lowering her eyes to caress his mouth, her thumb still lingering just below his bottom lip.

"I really wish I was brave enough to kiss you," he sighs, his pout falling apart when she laughs at him for it. "I know you just ended things with Josh, but when you're ready, I could be that person. The one who dives in with you."

The smile that blossoms on her lips is breathtaking and he can't help it, he drifts in a little, stops just short of her mouth with his forehead sealed to hers instead.

"We should wait a few days," she concedes, gliding her fingers into his hair and tipping her chin upwards to nudge his nose with her own, the intimate brush sending sparks exploding like fireworks through his ribcage. "But things with Josh... they've been over for a while now, so maybe... after this case?"

"Yes," he says with relish. "We'll get through this case, Beckett. Get through it together, partners."

"And then we'll be..."

"More. Just - more. Everything. It's been more for a while now, Kate," he mumbles, all of it spilling out too quickly for him to control. "More than hanging around just to annoy you, more than riding out to murder scenes to satisfy some morbid curiosity. It's been about more than the books for such a long time-"

The hands cradling his skull hold him steady as she lifts her mouth to his, their lips fitting together in a gentle, perfect collision that steals his words, his breath, and wipes his mind clean of anything but her. Castle kisses her back, revels in the scrape of her fingers through his hair before they descend to his neck, allowing her arms to follow suit and draw him closer, allowing him the press of her body to his for the second time in a single hour.

He sucks her bottom lip into his mouth, attends to the flesh with his tongue while his hands span at her back, just below the wings of her shoulder blades, clutching the material of her shirt when a soft moan hums past her lips.

"Too courageous, Beckett," he gasps into her mouth, planting his hands on the edge of the stove behind her, where she's somehow managed to become pinned against. Oops.

Kate chuckles, too low, too throaty, and knocks her forehead back into his, takes a moment to rest there as they both catch their breath.

"Pretty daring yourself, Castle," she grins, canting her hips forward to nudge his, choking him up before gentling him with the stroke of her fingers at an unshaven spot on his jaw. "Crazy," she adds on a whisper, earning a curve of his brow, but her cheeks flush, as if she hadn't meant to breathe the word aloud.

"What's crazy?"

"This entire day," she admits, shaking her head against him. "But right now just... wishing this case was over so we could... do some more courageous things together."

The laughter booms from his chest without consent, but it only causes her to smirk, smear another kiss to his jaw.

"Justice for your mom first, brave activities after."

"Brave activities no matter what happens," she corrects him, breaking the kiss of their foreheads to drop hers to his temple, her hands slipping from his face to give her arms the freedom to snake around his waist, holding on.

It feels like a dream, from the nightmare of throwing Vulcan Simmons into a mirror with his hands around the man's throat, to this moment in her arms with her kiss still ripe on his lips, but he dusts his lips along the shard of her cheekbone before laying his cheek to rest against hers, trailing his hands down her back and savoring the increasingly familiar sensation of Kate Beckett in his arms, the taste of her lingering in his mouth, and the promise of her words echoing in his mind.