A/N: Happy Castleversary everyone! In honor of #CastleFanficMonday, here's a little oneshot I've had sitting on my computer for almost a year!

Provocation

Summer hangs between the buildings of New York like the heat from a sizzling pan of bacon. The air is still; the humidity thick as oil. It's the kind of heat that Castle prefers to stay out of, but instead he's running full-pelt after his wife who, in turn, is running full-pelt after their suspect. The sleazebag knocks over a tower of boxes, trying to take Beckett down, but she springs nimbly over them. Before Castle can process the flash of foil rolling down the sidewalk towards him, the warm soda cans start to explode with a cacophony of pops and hisses. It's not as bad as marbles, but the last thing he needs to to slip like a cartoon character and land on his ass. He loses his speed trying to dodge the cans, but he gets to watch his wife gather up a sprint that closes the gap on their guy. She's a force to be reckoned with, even in heels.

The guy turns suddenly, and Beckett rounds the corner of 51st and 9th after him. Castle's heart shudders as he loses sight of her. He's been wondering lately if shadowing her is still the best idea. The combination of his age and all the ludicrous things that have happened to them over the years is on the verge of giving him some sort of attack.

When his heavy legs (when did they get so uncooperative?) finally carry him around the corner, he's too late to help her take him down. Beckett leaps onto the suspect's back, her hair flying out around her in the sun her like some Amazonian goddess.

His feet pound a decrescendo on the pavement, slowing with the wheeze of his breathing. When he catches up to them, he doubles over with his hands on his knees, panting uselessly as Kate wrenches the man's arms behind his back. She digs her knee firmly into his quad and snaps her cuffs around his wrists.

The guy, Russell Godfrey, is a squirrelly little man with more venom behind his crimes than the usual suspect. He squirms under Beckett's boot. He's short; stocky and solid in a way that makes him look like an overstuffed sausage, and there's a layer of dull grey grime on his skin. His eyes are small and shrewd, glinting black in his pocked face. When they'd questioned him yesterday he had a cocky swagger and a voice that carried the gravelly whisper of a lifetime smoker. Castle can smell him from five feet away - stale corn tortillas and cheap tobacco. Beckett never ceases to amaze him, especially not in these moments where her jaw is iron and her nose un-scrunched. A little thing like body odor isn't going to make her back off even an inch.

He calls dispatch, introducing himself as One Lincoln Forty. He still feels a twitch of pride that she lets him use her call sign. Within minutes a black-and-white is rounding the corner. In that time, Godfrey manages to spew out a truckload of explicit nonsense and a several phrases that should be illegal, especially when directed at his radiant, fierce Detective — no, he reminds himself — Lieutenant. Lieutenant Kate Beckett, as of two weeks ago.

Castle keeps his distance, but doesn't take his eyes off his wife as she walks the perp over to the squad car and shoves him against the back door. No way they're letting this weasel ride in the back of Beckett's service vehicle; she doesn't have a grill between the front and back seats and rumor has it Godfrey is a biter.

The uniform pushes Godfrey's head down to pack him into the squad car. The slimebag has the balls to say "Aw, man, I don't get to ride with the lady cop? Would have liked to put somethin' in her pretty mouth, if you know what I mean."

The officer slams the door and swivels, young and wide-eyed, to Beckett.

"Sorry about that, Lieutenant."

"Not your fault, Brady." Now get out of here before Castle blows a gasket, she adds silently.

Sure enough, when she turns to Castle, he's fuming. His teeth grind and his eyes are trained on the back of the departing car with an intensity that could make crosshairs appear. She's seen this seething, quiet anger before, when Alexis was kidnapped.

She takes his hand, running her thumb along the deep crease of his life-line. "Castle. Calm down, babe. Snap out of it."

"But he - "

"I know exactly what he said, and I've heard a lot worse. Let's just go, okay?" She's gentle with him as she guides him back towards her car.

Castle acquiesces, but he's still boiling. For such a genial, friendly guy, his temper can be as hot as an East Coast summer when it comes to the safety of his wife and daughter. By the time they reach the precinct, not even the constant pressure of her hand on his thigh has snapped him out of it. She'd even let him cover hers with his larger one in an effort to stroke his manly ego.

The ride up in the elevator is tense. Castle wants to say "I don't want you to interrogate him," but that's a surefire way to get tossed into observation. Beckett doesn't let anyone screw up her interrogations.

So instead he tugs on their joined hands. She jerks into him from the surprise of it. His fingers find their way to her neck and he takes just a second to stare into her eyes, reminds himself that she's not a delicate flower that needs protecting. But God, it's sometimes hard to remember when she stares up at him with such clear, soft, trusting eyes. That look she only gives to him.

He brings his lips to hers, ghosts over them until her eyelids drop, and then he presses his forehead against hers and speaks.

"Sorry for freaking out back there."

"It's okay," she murmurs. "You had a pretty good reason. You alright now?"

"Yep. I'm over it."

She cranes her neck up to catch his lips, pressing firmly into him and driving him back against the wall. The kiss is brusque and hard and she pulls back from him with a smack.

"Good," she says. "Now quit kissing me at work or I'll have to fake a cold, take you home and waste one of my sick days."

"Oh, I'm not sure it would be considered wasted," he smirks, marginally pacified. The elevator doors slide open and he follows her towards Interrogation One.

They're only a few minutes into the interrogation when Godfrey catches a look in Castle's eye. Maybe it's pride, maybe it's just a hint of soft adoration.

Usually, it's not a problem. They're very good at keeping their relationship under wraps in front of suspects. At work, they act exactly like they've done for the past ten years. Maybe the problem is that their chemistry, their obvious care for one another, has been on display, unbeknownst to them, for that entire time. The addition of a sex life, and then marriage, hadn't really changed much in terms of their workplace demeanor.

She wears her wedding band, a smooth platinum circlet, but the engagement ring stays at home. Castle keeps his hands under the table, so Godfrey just makes an assumption.

"Yeah, she's got a pretty tight ass. Never seen anything like it on a cop. You looking to get into this one's pants, huh? Join the club, buddy."

"Mr. Godfrey." Beckett's voice drips with disdain. "Let's get back to the subject of why you were at Anna Hull's house the night before last."

Godfrey laughs, a rusty snort that makes Castle cringe. "Oh, your cop's a feisty one, pal. I bet she likes being on top. But I think you and I are out of luck. I think she's taken." Godfrey points to his own ring finger and waggles his wiry black eyebrows.

"Mr. Godfrey," Beckett says, "if you don't feel like cooperating, I'm more than happy to stick you in holding for a few hours. Who's in today, Castle? I think I saw Blackbeard in booking earlier. How tall is he, do you think?"

"Oh, six-four, at least."

"300 pounds?"

"All muscle. Every inch covered with tattoos."

"Yeah. I seem to remember him having a daughter. He's got serious issues with people who attack teenage girls."

Godfrey ignores her, keeps on chatting to Castle like they're drinking buddies. "How long you been working with her? A hellcat like this, I bet she needs a lot of attention in the bedroom. Maybe hubby's not doing enough for her, hmm?"

Beckett mutters something under her breath, feeling her husband's grip on his temper loosen.

Godfrey doesn't shut up. "Maybe you could work on her one day a week or something? Take a little off his plate?"

Castle flips the table.

He's seen her do it before, but his re-enactment is not nearly as smooth. The table lands on Godfrey's stomach. While he squirms to get out from under it, Castle's up from his chair and circling the wreckage. Beckett latches onto her husband and wraps her hands around his biceps. He's always so much more solid than she expects, and if she wants to stop him she'd have to use a move that would leave a mark and cause quite a bit of residual pain.

Castle tears out of her grasp and lands a punch on Russell Godfrey's nose. There's a sickening crack and the hot smell of blood. Esposito blasts into the room, but Beckett stops him with an open palm to the chest. Castle's hurting, and he doesn't deserve to be physically hurting as well.

She doesn't yell, doesn't try to grab him again. She just jumps on him, drapes herself over his back and presses her lips to his neck. He stops just as he winds up for his next punch, the feel of her pressed against him jolting him out of his assault. He rises slowly, staggering up to his feet under her weight. She doesn't let go. She can feel him start to shake as logic rushes back in, as he realizes what he's done.

Godfrey is clutching his bleeding nose and cursing, but he apparently he hasn't got the point at all.

"Damn, man, you guys having an affair already? That why you punched the crap out of me? Is she your booty call?"

Castle stops shaking and stiffens, drawing himself up to his full height.

"Actually." His voice is murderously calm now. "She's my wife."

Kate can tell how much he loves being able to say that. She can't help it - she smiles, presses her wide, stupid grin into his shoulder blade.

Castle squeezes Beckett's hands where they're clasped over his stomach and gently peels her off. He leaves the room with an apologetic smile meant only for her. Esposito helps her right the table, then takes Castle's place in the interrogation. It's his way of saying he won't mention her husband's behavior.

"Right." Beckett pulls her chair up to the table and taps the mic. "Mr. Godfrey. We are sorry that you managed to knock the table over and hurt yourself. We'll get a medic to see to you after we're done with this interrogation."

She knows Castle will be watching from observation. She draws her hand over her mouth to hide her smile. He's fiercely protective, gruff, and a little bit of a caveman on occasion, but he's hers.

A/N: I clearly just wanted Castle to say 'She's my wife.' ;) Let me know what you think!