Author's Note: This is my first Castle/Caskett fanfic. I don't know why I waited so long to attempt one, but here it is. I've had this idea in my head since I saw "Fool Me Once" and that glorious scene with Beckett in the tub. And then we heard about the sex scene on page 105. So then I started thinking…what if Beckett had gotten to that part of the book when we saw her in the tub? And then this was born. Thanks to blissfulbells and wickedlychenzel for reading what I had and giving me feedback. Much love. XOXO

Disclaimer: Castle is not mine, obviously. Neither is Heat Wave. Believe me, Kate Beckett would be doing very dirty things to me right now if this was mine. Kate Beckett and Stana Katic both. ;)

The candles flickered, sending shadows dancing across the hardwood of the bathroom floor. Kate Beckett slipped off her robe and dipped one foot into the bathtub, starting with the tip of her big toe and continuing until her whole foot was submerged. She did the same with her other foot, and then slowly lowered herself into the tub, careful to keep her hands relatively dry. She picked up her advanced copy of Heat Wave, opened to page 100, and with a smug smile on her face and a glass of wine in her other hand, she continued reading.

This was the type of evening Kate loved to have, but rarely got the chance to. More often than not she worked through the night, burning the midnight oil to catch the killer. She would go days without getting a full night's sleep. Her bathing habits consisted of a quick five minute shower to scrub the grime off of herself before she went back to work. She seldom allowed herself to relax once she got back to her empty apartment. But there were some nights, such as this one, where Kate indulged herself. She'd run a bath. Light candles. And read a good book. Nights like these allowed her to strip away all of her armor and hard exterior. She could just be herself. A woman. In a bubble bath. Reading a mystery novel.

And what book could possibly be better than her advanced copy of Richard Castle's Heat Wave? Many of the nights Kate allotted herself like this one was spent reading a Richard Castle novel. Flowers For Your Grave had been so captivating, Kate had sat in the tub for an extra hour and a half after the water cooled, refusing to put the book down for even just a minute to get out of the tub. She would never admit any of that to Castle, ever—his ego was far too inflated as it was. But she loved his books. And although she hated the idea of being the inspiration for his next series, there was a part of her that couldn't believe it. Detective Kate Beckett, a muse for the legendary mystery novelist Richard Castle? Her pulse quickened simply thinking about it.

Heat Wave was no disappointment, either. Like the rest of Castle's novels, the characters were fully developed, the storyline riveting, and the dialogue fast paced and witty. Kate thought Nikki Heat was exceptionally well written, and she could see how Heat had been influenced by her. But Nikki was fictional, and could do and say things that Kate never could. She wore outfits that Kate could never wear to work. She talked to people in ways Kate would be thrown off of cases if she talked like that. And the way she shamelessly flirted with Jameson Rook, who was so obviously based off of Castle himself, would never fly with the real Kate Beckett.

The arrogant bastard thinks he knows the wilder side of me. Kate thought with a smile, shaking her head as she turned the page. Nikki had invited Rook to stay at her apartment for a bit, and the tequila had just been brought out. Kate couldn't remember if she had told Castle about her fondness for tequila and margaritas or not, but somehow he found out and found a way to place it in his novel. And now his main character, based off of the good detective herself, was quite seductively licking salt off of the handsome reporter that mirrored Castle so much. Kate felt a shiver course through her as she read Nikki's actions.

"Nikki didn't look up at him because she was afraid if she did she would change her mind instead of taking the leap. She bent toward his hand and darted her tongue out, quickly at first, but then, choosing to slow the moment down, she lingered there licking the salt off his skin."

Kate shifted slightly in the tub, causing the water to ripple and move around her. The sensation of the water combined with the steamy scenario in the book made Kate's breath hitch, and she closed her eyes for a moment, letting herself feel the emotions Castle's book was stirring inside of her. She felt hot, too hot for the bath she was in. But the water felt so good against her tired skin, and she liked the intimate nature of reading Castle's book in a setting like this one.

Kate had a faint idea as to where the book was heading, and she surprised herself by feeling more flattered and aroused than angry. This was a character based off of her, after all. But Kate couldn't summon up any anger or irritation towards Castle. All she could think about was the scenario these two characters were in, and wondering if it would be as electric if it were her and Castle instead of Nikki Heat and Jameson Rook.

She had finished her wine earlier, while on page 103, and had placed the empty glass on the table by the tub. Her hand, now free from holding anything, began to trace light circles on her upper chest, right near her collarbone. As she continued reading, past page 104 and onto the beginning of chapter 10 on page 105, her fingers slowly dipped lower, beneath the water.

"One of his hands began to reach for her blouse but hesitated. She clutched it and placed it on her breast. The heat of the room was tropical, and as he touched her, Nikki felt his fingers ride the slick of perspiration above the dampness of her bra. She lowered her hand and found him and he moaned softly."

Kate read the words, her mind creating the images that were being described on the page. She felt her face flush, her stomach tighten and something lower, deeper inside of her start to coil. Her hand beneath the water cupped her breast, and she moaned softly as two of her fingers pinched her nipple, rolling it just enough to make it ache a little. Images of Castle's own hand and fingers replacing her own made her more eager for more. She looked back to the page, with Nikki reaching down and touching Rook. What would it be like to touch Castle there? I bet he's not lacking in that area Kate thought.

She wondered what went through Castle's own head as he was writing this scene. What was he thinking about? Did he imagine his characters? Or was it him and her, falling slowly together in the heat of the night, hips rocking and mouths open, gasping and moaning into each other? As Kate continued reading, her hand moved past her breast and down further, settling in between her thighs.

Two fingers slipped beneath her folds, and Kate gasped at the sensation. It had been a while since she had indulged herself in this kind of intimate behavior, and her nerves were already on edge from Castle's hot and heavy sex scene. She wanted to make this last, but Kate wasn't sure how slow she could take it. Not when she was imagining it was Castle. She closed her eyes once more, imagining Rick Castle in the tub with her, his fingers dipping further inside of her, first one, then two fingers feeling her walls clutching at him.

"Oh God" she breathed. She took a moment to revel in the feeling of her own fingers inside of her. Slowly, she opened her eyes and turned her gaze back to her book, picking up where she left off.

"Their wet skin made a slap as her chest landed on his. She reached down and unhooked his belt. Then undid his zipper. Nikki kissed him again and whispered 'I keep protection in the nightstand.'

"'You won't need a gun,' he said. 'I'll be a perfect gentleman.'

"'You'd better not." And she pounced on him, her heart pounding high in her chest with excitement and tension."

Kate moaned, moving her fingers in and out. She bucked her hips against her hand, creating miniature waves in the tub. Although she was reading about the passion between Nikki Heat and Jameson Rook, it was Castle's name on her lips as she felt her climax building.

"A wave crashed over Nikki and washed away all the conflicting feelings and misgivings she had been wrestling with, and she was simply, mightily, powerfully, swept up. In that instant, Nikki became free. Free of responsibilities. Free of control. Free of herself. Swirling, she clung to Rook, needing to feel every part of him she could touch. They held on with a fury, his passion matching hers and they explored each other, moving, biting, hungry, reaching and reaching to satisfy what they ached for."

Kate increased the speed of her fingers, plunging deeper and harder into herself. She placed her thumb against her clit, making tight circles against the sensitive bud. She was so close, almost there. Once more she closed her eyes, picturing Castle's fingers inside of her, his tongue against her clit instead of her own digit. She stroked harder and faster, and with one more sweep of her thumb on her clit, she fell apart.

"Castle," she moaned, riding the wave of her orgasm. She slowed her fingers, moving her hips less frantically as she came down from the ecstasy. Slowly, with a trembling hand, she set her copy of Heat Wave down on the table by the tub. The water had cooled and was now luke warm. Kate took a breath and sat back for a moment, gathering herself. After a few moments and several deep breaths later, trusting her legs to support her, Kate stood from the tub. She grabbed her towel from the rack by the sink, and wrapped it around herself.

She blew out the candles and picked up her wine glass and the book. With a small smile on her lips, she turned and left the bathroom, thoughts of Castle and page 105 on her mind.