A/N: Based on a prompt from the CastleFanficPrompts page on tumblr. As usual prompt at the end.

Dedicated to: Miranda_Jayne for a million multicolored reasons. *hugs*

You just have something that I need

I can't put my finger on it

You can put yours on me

She told him she hadn't read it.

She lied.

Lied more than once. Didn't want the smug satisfaction creeping into her fantasy and ruining it.

She ignores the voice at the back of her head that whispers it would have made it better. Hotter.

It's not the man she wants, she lies to herself, it's only his words. And she pretends the entire day hasn't been a prelude to what she knows is coming. No anticipation racing under her skin.

It doesn't work. Doesn't help. So she stops.

Kate won't skip straight to the page, though she wants to. She doesn't begin reading the moment she's through the door, though it would be easy enough. But it's been thrumming under her skin since Castle mentioned it, still under the assumption she doesn't know, doesn't have the knowledge that he's thought about her - sexually.

She should be mad at him for it, for turning her on and annoying her and so many things she's not sure she could list.

But she's not.

She refuses to try and explain to herself why.

No, she doesn't skip straight to the page, she forces herself to make an evening of it, let the sinful truth of what she's about to do, what she's contemplating, build within her with every preemptive action.

She runs the water, hot, steamy.

She uncorks the wine. Red, something with a bite of spice. Something husky that she tries to pretend doesn't remind her of the scent of Castle, the one she catches as he breezes by with a flippant retort thrown out to itch its way under her skin.

She sips at it to have the taste of him over her tongue.

Kate maintains the ritual, adds a splash of oil - cherry and vanilla - and forces herself to wait as the water creeps slowly up the side of the tub.

She's naked now, staring at his novel.

She's been through the entire thing cover to cover once already, and the sex scene had startled her, thrilled her, aroused her. It played into thoughts and fantasies she's been denying for months.

Now, in the comfort of her own home, she's giving herself one night where she doesn't have to pretend.

Her nipples are taut when her robe slips to the floor and she brushes them with the pads of her fingers. Tweaks and pinches.

In her mind it's Castle's hands on her body. Rough. Knowing.

Breath coming quickly already, she understands her own body well enough to know it will be quick, the first time she comes, leaving her craving more. Open, wet and hungry.

Her fingers shake as she climbs into the tub, the heat of the water caressing between her legs so she hisses, rocks a little, preparing for the friction she's desperate for.

It won't be long.

The room is thick with steam, the book large between her hands. She lays back in the water, allows it to creep over her chest and tease her nipples. Kate rubs her thighs together, flexes, flips through the book to the chapter she paused at, knowing the sex scene is only a few pages away.

She wants to work toward it slowly. Let the heat between each word settle between her thighs as she imagines a Castle, dark with guilty pleasure, locked in his office, behind his desk. Rock hard as he writes the way in which she breaks apart.

She imagines inviting him home with her one night after a case, telling him he wrote it wrong and he needs to see, first hand, what she really looks like when she comes.

Could he capture the flush of her skin? The wetness that would invite him in?

Would he read it back to her and make her come harder than ever before, turned on, seduced, dazzled by the way he sees her?

Nikki gives in in all the ways Kate wants to. She kisses Rook and Kate closes the book, dropping it to one side of the tub, no longer needing it.

The words are gone, but the images he created are so vivid in her head that she doesn't need them. Sliding her hand down her stomach, Kate wastes no more time with teasing.

She doesn't want foreplay tonight, doesn't need more than the image of Castle in her mind and the slip of her fingers between her swollen lips.

She's already thick and juicy against her fingertips. She hisses at the change, the coldness of her hands against her burning flesh.

It feels amazing. Knowing herself, touching herself. Pretending all the while it's him.

She doesn't hear the knock as her fingers slide inside, grazing the soft ridges that bend under her insistent will. She needs hard, deep, toe curling penetration.

She doesn't hear the call of her name as she rocks her hips, spreads herself wider, adds another too slender finger, wishing she had his long thick fingers buried inside her instead.

She doesn't hear the door creak open as she breathlessly calls out, "Castle." Unknowingly inviting him in.

She doesn't hear the sharp inhale of his breath when she rises up out of the tub, her knuckles grazing places that send sparks though her vision.

Once she was alone and suddenly she's not.

Her eyes flick up and he's there in the doorway. Figment or phantom, either way, perfection. His eyes on her as she slides her fingers deeper, kick-starting the ripple of her muscles.

She gasps his name again, "Castle," and lifts a pleading hand to her fantasized writer.

He comes at her through the steam, his eyes darting between the hand pumping between her legs and the one curled on the edge of the tub, open in offering.

She invites him closer, drinking in his stunned expression. She imagines him climbing in beside her and pulling her into his lap. She imagines his fingers inside her and his cock in her mouth. Visions of her wet hair splayed across the bed as he drives himself into her, her grip on him tight enough to leave bruises, flood her mind.

Why won't he come closer?

"Castle?" She pleads and the sound of shoes on the floor breaks through the din. The fog of lust lifts enough for her to know he's real. He's here.

His eyes drop to his book, dart up again in shock when he finally realizes he's watching her get off to the words he wrote about them.

She stops moving.

Stunned, unsure.

Her breath a ragged pant that threatens to send her spilling over into orgasmic bliss. Every hard breath moving the frozen hand between her legs just enough that she whimpers.

He steps closer, eyes wide, waiting for a threat or curse that never comes.

Her silence makes him bold. She's glad. Not sure she could find the words to invite him to her.

"You left your door unlocked." He stops, staring down at her as she arches up, knowing he can see every inch of her naked skin through the paltry layer of bubbles that still lingers. He can see her hand caught between her legs. His stares there for a long moment, as if waiting movement that never comes.

His sigh is almost as desperate as her own panting breath.

When she doesn't speak, or move, Castle reaches out a lone finger, trails a bead of moisture to her wrist, his mouth falling open when she whines.

Her hand still frozen between her legs, fingers up inside her, she shifts her hips, whimpers again at the ripple of sensation that tears through her. She was so close.

So close.

"Don't - don't stop." He pleads, eyes on the rosy flush of her chest, "I'll lea-"

"No." She bites her lips, shocked at her own words. But she's wound tight and hard and he's adding to the thrum of desire racing through her. She always knew he would, suspected his touch would drive her so far beyond insanity she'd never be able to survive again without it.

He freezes then, drops down immediately at her side. He's stunned and truthfully so is she, this isn't like her, like them. But she wants it.

Every cell in her body craves it.

In awe he asks, "Let me -"

She shakes her head, not yet. Not yet.

"Re - read to me?"

The request escapes her lips before she can stop it, but she doesn't care. Kate's glad it's set free because he's already lifting the advance copy of their story from the floor and flipping the pages, his eyes never once leaving her.

"You." He demands, eyes back on the hand between her legs, "You first, Beckett."

He doesn't read until her fingers are moving. Slow, steady strokes she tries to keep in time with his voice.

"Tentatively -" he begins, not even looking at the book, giving her time to find her rhythm, "- slowly, each drew an inch closer, each still silent, each still holding the other's steady gaze."

Kate can't look away or drop her eyes from his when he closes the copy of his novel in his lap, all pretense brushed aside as Castle slides it across the room. He doesn't need it to remember what happens, eyes locked with her own, Kate suddenly knows her fantasies of him behind a desk, winding himself higher and higher, aren't locked in fiction.

It's fact.

He wants her just as much as she's been craving him.

Castle rises onto his knees and his fingers drift up her arm, eyes seeking permission. When she doesn't speak - can't - he resumes the story, nudging her hand to keep up the steady motion between her thighs.

"Whatever worry or uncertainty or conflict she'd felt before, she pushed it aside as too much thinking."

And Kate did, in time with his words she let everything else drift away from her, gave herself up to Nikki's story, losing herself in the erotic cadence of Castle's voice.

"At that moment, Nikki Heat didn't want to think. She wanted to be."

"Yes."

She hisses, fingers curling.

Kate wants that too. More than anything else. Absence of sound and light, life. Nothing but the feel of his touch on her skin.

Why not?

Arching back in the tub, Kate reaches for his hand, nodding when his eyes hold her own and question, "Castle - touch me."

His fingers slide immediately below the surface of the water, barely a splash of sound followed by the brush of knuckles over her stomach.

It's electricity and lightning all at once. Her body snaps to attention, sensing his approach, knowing that whatever he's about to do will utterly destroy her.

Kate's eyes are still on him, but flutter shut at the stoke of his thumb across her pubic bone. She forces herself back, wanting to watch, swallowed up instantly when she falls into the darkness of his pupils.

He's staring at her with raw hunger, vivid and thrilling.

Castle traces the soft dip of her navel, down along the length of her leg. He stops, watches as she bites her lip, gripping behind her knee.

"Kate?"

She nods, goes limp, allows him to pull her leg up and over the edge of the tub until she's splayed and open for his touch.

Everything inside her quivers, aches, contracts with expectation.

Blood pounds hard in her ears, the water too hot against her skin, the steam sizzling the air between them.

He makes her wait. Stares down at her naked skin as though memorizing every reaction, collecting every rise of goosebumps, every hair that stands on end.

She can't bear it. Her body is on fire.

"Castle?"

His fingers trail back slowly, hesitate at her thigh, listing where the water laps his fingertips.

Her hips bob, invitation clear. But he waits, wanting words, words that match his own.

"Please?"

He smiles, but doesn't make her beg.

Dropping below the surface of the water Castle traces her slowly, finds her hot and wet, slippery when he parts her. He rises up and presses his lips to her arm where it lays along the edge of the tub.

He's pleased with what he finds.

He nips at her elbow when she squeezes her thighs together around his hand.

She growls, opens her mouth to demand, berate, control. He's already one step ahead of her.

Nudging her thighs apart once more, Castle uses the tip of one finger to draw a long, slow line. He dips inside where she's more than ready for him, only to skim up and circle. Slowly. He learns her shape, the way she swells and opens beneath his touch. The way she feels around his fingers.

It's excruciatingly slow.

Erotic in a way she's never experienced before.

Her knuckles porcelain white either side of the tub as she tries to hold on.

Castle hums his enjoyment. A dark sound that makes her whine.

She's wet and close, he can feel it in the quiver of muscles that beg to cling tight to his fingers, but he holds off pushing them inside her, wrapped up in the silky smooth feel of her pleasure sliding over his digits.

She shimmers in the heat and steam. Body lax and tight at the same time, needy, trusting.

He would never betray her.

Intent on nothing but her pleasure, Castle strokes her lips wide, adds another finger and watches her lose the battle with her eyelids. Her eyes scrunch closed and the jerk of her hips sends a thundering rush of water up and over the bathtub's edge.

A devilish idea creeps up on him and she catches it too late to stop him.

"A wave crashed over Nikki -" he growls low, grinning when her eyes startle open again, " - and washed away all the conflicted feelings and misgivings she had been wrestling with -"

She won't survive it now. This far gone, their story, his words, and his fingers working her body. She'll be lucky if she doesn't pass out.

"Castle, please - oh -"

Castle holds her open and finally pushes all the way inside, biting down on his tongue at the sinful cry that escapes her lips, wishing he could lean over and taste it.

He doesn't. Not yet.

He adds another finger, testing the limits of how much she'll take. She's already tight around him, but her elastic muscles strain and give and the drawn out, wicked sound she utters, makes his entire body clench hard with need.

He wants to be inside her, stroking himself deep.

Castle draws his fingers out slowly, twists his wrist and pushes them back inside, feeling the hard bite of her muscles contract around him.

The first flutters of pleasure racing through her.

He begins again.

"She was simply -" he strokes her with his thumb, a slow rhythm that makes her hips dance in the water, "- powerfully -" Castle thrusts into her, hard, strumming his fingers inside so she cries out.

"Yes, don't - don't stop."

"-Swept up."

Her body thrashes in the tub, breasts bobbing. Each crash of suds over the side revealing more and more of her to him.

Castle watches, mouth open, as Kate lifts one hand, reaches out, strokes over her nipple and pulls hard enough that he can feel her grip all along the length of his hardened cock.

"Nikki became free." He husks, his own words in his head suddenly filled with more meaning than they ever have been before.

Because of her.

"Beckett."

Her eyes find his and Castle rocks up onto his knees, plunging a second hand into the tub. He holds her thighs wider apart so he can pump his fingers into her furiously, touch her breasts, her thighs.

Anywhere on her gloriously soaked skin.

She groans.

Bright red and breaking apart, he's never seen Beckett look more beautiful.

"Castle, please -"

"Free of responsibility."

"Oh, god."

He brings her higher and higher, wanting her to let go.

"Yes."

"Free of control."

He wants her to soar.

"Yes."

"Free of herself." He twists his fingers and growls her name.

"Fuck, yes."

"Beckett.

Kate cries out loudly as she breaks apart around his fingers.

Voice a croaked and near silent scream of shock as the orgasm ricochets through her.

Hard, tight contractions twist along the lengths of each one of his fingers so evocatively that Castle finds himself rocking his body in time. Rubbing himself against her tub.

Splintering into pieces beneath his touch, her hips splash frantically in the shallow water.

Rock hard, desperate, the sight before him, torn from his own fantasies, one he could never give up, Castle keeps his fingers moving. He'll never stop. Not when she looks like that.

Head thrown back, cresting starlight she chokes, "Castle, god." Panting, hips slowing, water gone and his shirt soaked through.

Each crest and peak seems higher, the fall harder, than the one before and his fingers continue dancing between her legs until she's squirming under his touch. Pushing him away, pulling him back. Bringing his hand to her face and licking his fingertips as she pants.

She can't catch her breath, can't remember the last time anyone made her come like that, face bright red, eyes huge and lust a lazy counterpart to the soap bubbles that spread over her skin.

Of course it was Castle. The only person guaranteed to get that far under her skin.

She doesn't care, she kisses him. Hard. Lets him get the faint taste of her on his tongue.

"Kate?"

She nips his finger, finally remembering to open her eyes.

He's grinning, shirt plastered to his skin so she can see every contour of muscle hidden beneath.

God, she still wants him.

"So, do you like the book?"

Even if he is an ass.

She laughs, grumbles, gives in to the elastic snap of tension between them. "Get in," she demands, pulling at his shirt until he complies, "and I'll give you my review."

Prompt: 2x04 Beckett accidentally left her front door unlocked and Castle ends up coming in and seeing Beckett in her tub taking pleasure reading his book.

Disclaimer: All italicized sections are excerpts from Heat Wave which obviously do not belong to me.