(Prompt: Beckett shows up for her second go at Castle's annual Halloween party in-costume AND in-character as Nikki Heat. She lets Castle fuck her, but only as long as he calls her Nikki.)

Chapter One : City Sun Set Over Me

May your trails be crooked, winding, lonesome, dangerous, leading to the most amazing view.
- Desert Solitaire, Edward Abbey

The acrid scent of the temporary dye makes her eyes water, but it's just as well. The tears leak from the corner of her eyes, smudging her eyeliner and mascara, and it completes her look. Just right. Her thick-rimmed eyes, smoky with sex and a tequila she hasn't yet had a chance to knock back, Kate blinks apprehensively back at her reflection in the mirror. Red velvet tendrils fall in ragged curls and scraggly waves around her face. Not orange – not like his daughter, not like his mother,definitely not like his first ex-wife – the color suits her surprisingly well, like a second skin she can slip into just for tonight. Delectable and sultry and too red to be natural, it's just the thing. Just what he needs to see. Just what she needs to be.

Beaten black leather moto jacket, cropped and shredded grey shirt, tight ink-rinse jeans that showcase the legs she knows he spends an inordinate amount of time staring at when he thinks she's not looking, and lace-up combat boots that she unearthed from the abyss of her closet - a relic of her wilder days – top off the illusion. A little Vice, a little punk rock, a little slutty. A lot of fun. She can be fun. She's still got Rebel Becks in there. Somewhere. She just needs to coax her a little closer to the surface tonight.

He'll never see it coming. She didn't see it coming. Didn't plan it out, not really. She was going to be Elektra. Really, she was. But inspiration struck that morning, when he once again couldn't keep his hands to himself at the precinct, touching her at any excuse. Passing a pen, brushing her neck when he helped her into her jacket, touch, touch, touch, touching all day long. She fumed and knocked off at 4, claiming she needed time to get her costume ready.

And it was true. Only, she didn't need time to get into something red and skimpy and totally impractical for battling supervillains. She needed time to get into costume, get into character.

Strapping her empty Glock 26 and a 'Detective Heat' nameplate into place to complete the look, she banishes the last nagging voice that tells her that this is a bad idea, that it's wrong, that it's not going to end well. She doesn't care. She doesn't want to hear it. One last check into the mirror, she takes a deep breath and looks her alter-ego in the eye defiantly.

It's almost an afterthought that she carefully removes the chain that holds her mother's ring, setting it gingerly on her jewelry box for later, when she can look at it again.

Alexis answers the door eagerly, her Hogwarts robe billowing behind her when she grabs Kate's hand, dragging her through the surprisingly near-empty loft. Suddenly, without the crowd as a buffer, she feels self-conscious, nervous. Exposed.

"Dad, the cops are here," Alexis calls, the only response a loud clanging from his office. "And this one is hot." Good. Alexis gets the joke. (As if that's what this really is – a joke. Oh well. Better his family think so.)

Steampunk Han Solo stumbles out, gaping at her as he struggles to clamp his Victorian-themed weaponry belt into place.

"Beck—" she stops him. Nips it in the bud. She's going to be what she has to be tonight, and it's not Detective Beckett.

"Detective Heat," she says, putting a playful smile to it for Martha and Alexis' benefit, keeping the hard edge of her voice just for him. "Detective Nikki Heat, 20th Precinct Homicide. There's been a crime."

His Adam's apple bobs as he swallows thickly, still practically undressing her with his eyes and staring at her like he's half predator and half prey, caught between the instinct to devour her and the instinct to run from trouble, because she can see it. He just knows – gut reaction - that they're playing a different game tonight. But he doesn't move. Martha and Alexis are still there, watching with apparently amused interest.

She chuckles darkly. If he's undone enough look at her like that with his mother and daughter right there, she can only imagine what he'll do when she gets him alone.

She's counting on it.

"What crime, Detective?" he replies at last, his voice just a little strangled, but his poker face mostly in place again. Good job, Castle; keep up.

"Telling me your party started at seven, for starters," she breaks character and takes in the fully-decorated but empty loft, deciding it might not be a good idea to torture him in front of his family. He's sufficiently distracted. Good. He doesn't seem to know fully what she's up to, and she'd rather keep him guessing until the time is right. Keep him in the dark, then light up his world like Times Square, New Years Eve.

The right corner of his mouth turns up sheepishly, his uncharacteristically unstyled hair flopping roguishly in front of his face and that just isn't helping anything at all because mmmm. "I made soup. You can't survive on Reese's cups alone tonight."

"How did you—"

His face splits wide into that irresistible Tom-Sawyer grin, and Alexis giggles. "You just told me. Come on, have dinner with us."

"Katherine, you really should," Martha chimes in. And what can she do besides acquiesce?

She's adaptable. Still doesn't change anything. She's just gotten a little delayed, that's all. Stamping Nikki down for the moment and focusing on being Kate while his family's around, she gives in.

"Oh, what the hell, alright," she says cheerfully, lets Alexis seize her by the hand and pull her over to the counter while Castle dishes out soup, and Martha chats with her like she just belongs there.

The guests begin filing in at 8 – a delightful mix of pop culture, slutty archetypes, and elaborate period digs - and is in full swing by 10. Everyone who's anyone is there. Castle's made it a grand event, soliciting donations for the NYPD's Widows and Orphans fund while expertly mingling with the men and women who run the city, who dictate the culture, who write the story.

She's one of them tonight. She's going to write the story. Or more precisely, Nikki is.

The music is loud and she has little trouble slipping back into character, allowing a Michael Jackson - Beat It era, naturally, one glove and all - impersonator to pull her onto what's been collectively designated as the dance floor in the middle of the living room.

(Detective Beckett doesn't dance like this. Nikki Heat does.)

The Prince of Pop gets more of a dance than he could have hoped for, and he holds her all wrong and he smells all wrong, like cheap booze and pleather, but she endures. It's all part of the plan. She can't see him, but she knows he's watching.

She can feel his eyes on her. Han Solo has moved through the crowds, polite and social as ever tonight, but his eyes have never left her for very long. Not for Mayor Weldon. Not for Patterson. Not for Harrison-freakin'-Ford, who he even pulled her over to meet, causing her to drop character for just a moment as her inner-fangirl took over and she laughed nervously when the actor asked her who made a better Solo, mischief gleaming in his crinkled eyes. Castle hung on her every word, still didn't look away from her.

Not for anyone. Not even for Gina. Not even for Gina dressed as Glinda the Good Witch.

That's the thought that brings a grim smile to her face. It's a rush, knowing she has him so interested, that he desires her not only physically, but that he craves her company, covets her input, wants her around his wealthy and powerful friends,shows her off. Almost like he's proud of her. Almost like she's his.

He's teased her for weeks, ever since they found their groove again after the standoff with Kitty Canary.

Even though she's got Josh. Even though he's got Gina.

Hasn't stopped him from teasing, from flirting, from holding her hand when the Triple Killer escaped, from walking too close, from spending all night at the precinct with her even when there's just paperwork, from inviting her into his home for poker or movies and isn't it convenient that Gina is never there when she is? It certainly hasn't stopped him from looking at her like she's his every fantasy come to life on occasion, and given what he writes in his books, she thinks she might be, tonight. If he's a bit sweet on Detective Beckett, having his Nikki Heat dropped in his lap is a dream come true.

If it hasn't stopped him, it's not going to stop her. She intends to make his dreams come true. And hers. Definitely hers. He directs, produces, and stars in her dreams, and she intends to make it come true. Just for tonight. Just a writer and his character, easing the ache, and then Nikki can slip back between the bindings and Detective Beckett can get on with life with this thing out of her system. They can go back to safe Josh and convenient Gina, and the unbearable tension at the precinct will be broken, one way or the next.

Patterson cuts in, dancing nice and respectfully with her, and he moves pretty well for an old guy. That does it. She spies him by the top of his head, brass goggles astride that messy flop of brown hair, inches above whomever he's surrounded himself with. And he's moving her way.

"Stealing my muse, James?" he virtually has to shout to be heard, even from 3 feet away. "Don't you have a computer generator to come up with your own?"

"No need to be jealous, Ricky!" Patterson replies jovially, "too young for the likes of me, though I thank Detective Heat here for humoring an old man."

Patterson steps away to cool down with a margarita and Castle crowds into her in his place. She inhales; drinking in the smell of him, letting him block out everyone else as they dance and he tries to not get inappropriately close to her.

Oh, but she wants inappropriate. He'll figure that out soon enough.

They find a rhythm, his broad frame perfectly complementing her, moving instinctively with her, just an extension of the mind-body collusion they find themselves falling into at work without really trying.

Beckett turns her back to him after snagging a tequila and lime shot from King Kong's tray, knowing the symbolism is not lost on Castle for one single second. She feels his eyes, knows he's watching every movement in the tight curves of her ass and legs, knows he's mentally undressing her, peeling her jeans off her, ripping the laces on the knee-high boots away, for the thousandth time already tonight. Swaying this way and that to some club tune, she meanders through the crowd slowly, so as to not attract attention. He follows every step of the way, and when she sneaks a glance at him, she knows he's into it. Clear blue eyes turned glassed-over and dark gray, mouth stitched into a hard line. His control is not long for the world and she's going to make him lose it.

The edge of the party reaches the closed door to his office, and he makes another error in calculation when he leans back into it, reclining casually as if she's carefully steered him all the way through the mass of writhing bodies occupying every inch of the common areas in the loft just to dance for him.

Detective Beckett takes one last look around the loft, spying Gina in the dining room chatting up the evening news anchor, paying no attention at all to where her ex-husband current-boyfriend has gone to.

Good.

Sidling up to him, she tries desperately not to think. She leaves Kate at the door. Nikki's in charge now.

Yanking the handle down, he stumbles backward as the door opens, and she follows quickly, grabbing his arm to stabilize him as she swings the door shut behind them.

"Hi," she grins.

Castle looks bemused, a little concerned, but still all in for whatever he must think she has in mind for him. He has no idea, as usual. If he's guessed at anything yet, he's not showing it. His poker face may work on his buddies, but not on her. Not on anyone who really knows him.

"Hi?"

His voice is still too loud, having not adjusted for the suddenness of private company, ears probably ringing from the deafening volume of the music. If half the higher ranks of the NYPD weren't here already, she'd not be surprised if the police were called. The benefits of influence, she supposes.

The sultry, sexy, slow burn of a new song covers any noise they might make, the low notes of an electric guitar and a bass sending shivers through the floor, up through her boot-clad feet to settle in the base of her spine, spurring her further, letting her continue to sway just a little, pretend like it's all part of the dance.

"Beckett-"

"Nikki," she corrects sharply, her tone acid, scowling at him and making sure he understands exactly where the line is drawn. She's drawn it, this line in the sand between reality and fantasy and right and wrong and forgivable and unforgivable, and it won't be crossed. Won't. It's already moved, and it's moved a lot, but she's in control and he won't cross her. He won't.

"Just Nikki."

To new readers, welcome. To repeat readers, welcome back. If it's been some time since you read TMWI, it may be different, slightly. I've reworked each chapter, up to current (as of November 2017/Chapter 21) to reflect a more coherent style and more consistent characterization.

I sincerely hope you enjoy it, whatever chapter you've come in on, and I appreciate all feedback. I will try to respond to all signed reviews in a timely fashion.