Disclaimer: The wording is mine but the characters aren't.

Based on episode 3.11 where Natalie Rhodes shadows Beckett for Nikki Heat character research.

Hope you like it.

Roving Heat

"Castle!"

"Let me in, let me in!"

"What?" She felt her confusion scrunch her brow but he was already squeezing past her before she could swing the door wider, almost clipping his face on the side of the jam as he shot an anxious look over his shoulder. She scanned the hallway and didn't see anyone on his heels. Taken aback, she didn't even have the presence of mind to berate herself for overreacting with cop instincts just because Castle had materialized at her door.

It was enough of a surprise that he was here at all. He helped carry the scant luggage she had reclaimed and acquired after her last apartment went up, but he certainly hadn't been here since she was fully settled just before the summer.

Speaking of summer, Josh was going to be here after his shift to pick her up and she hadn't even started getting ready.

She quickly shut the door and tried to calculate the odds of balancing her night out l with whatever Castle-ness she was about to be enveloped in. They weren't favorable. Having braced herself for family trouble, paranoia, or even a crazy theory he couldn't keep to himself, she was left further off-kilter to see that he looked relatively relaxed now he was inside. The panic on his face when he pushed past for entry had set her nerves on alert, thinking of worst case scenarios; a mugger or homicidal fan chasing him…If he wasn't screaming at her yet, it looks like she had been over estimating whatever had driven him here. Already he seemed more interested in the décor of the room than his own problems, his eyes flickering around restlessly in keeping with the residual nervous energy she could see was still pent in his tall frame.

"Castle, what the hell is going on?"

"It's Natalie," he groaned, recaptured. "She won't leave me alone."

Then again, maybe she wasn't paranoid after all.

"Could you explain that to me?" she asked.

"She's following me everywhere!"

"You were the one who said she was just dedicated to the role." What was Natalie after this time if not…character research? With no 'permission', what could she be doing to make Castle this jumpy?

"That's why she's following you!" he protested. "She's not playing Jameson Rook. Besides, I haven't heard the word 'research' since she pushed me against a wall."

Kate bit back the irrational jealousy at the image. It had nothing to do with her; she was going out with Josh tonight.

"So if she's not researching, what does she want with you? To talk about her character? Ask you about…" she caught the uncomfortable look on his face. "Oh," she said, understanding.

"Apparently she doesn't take no for an answer."

Kate felt a burn of anger spice the jealousy and she tried to stay focused. Apparently Natalie decided she didn't want to wait for permission. Fans they saw around the city, asking for an autograph over coffee didn't bother her anymore, but Natalie Rhodes' single-minded determination to get her partner into bed for character research set her teeth on edge and teased her blood pressure up.

"I feel for you, I do," she told him. "But I don't see what I'm supposed to do about it."

"Can't you just hide me?"

"Hide you?" she snorted a laugh. "Until she gets back on a plane?"

He looked at her pleadingly. "Please, Beckett. She already charmed my doorman. It's not safe at home anymore."

"She can't be that bad, surely."

"She sat on my lap – in front of Alexis! Please!"

"Okay," she breathed, pressing her fingers to her temples. "Okay… Places to hide you…"

"Can't I just stay here?"

"No, you can't," she shook her head lightly. At his hurt expression she elaborated reluctantly, "I'm sorry, but Josh is picking me up in an hour."

And there it was; the slightest tensing of the muscles around his eyes.

"What about a hotel?" she offered, not caring that her attempt to gloss over her boyfriend's imminent arrival was painfully transparent.

"I tried that, but she found me."

She felt her mouth drop open just the smallest amount, "You're kidding."

"I wish I was."

"How?"

"I don't know," he swallowed. "Maybe she got someone at the precinct to run my credit card."

Unfortunately, that was a very real possibility. A bat of her eyelashes and Natalie could get half the men to do anything she asked. Probably the women too. Sometimes she really didn't like famous people.

Like authors who were friends with the mayor and got themselves a gig shadowing her? She asked herself sweetly. She had been livid at the time…the boys, still new to her team at the time, thought it was hilarious, seeing her get so wired up.

"Can you stay with the guys tonight?"

"Ryan and Esposito?" he sounded incredulous.

A tinge of resentment washed over her at his reaction. Sure Ryan just got engaged, but he didn't have to sound so appalled she had suggested he hole away with them for a night. What was wrong with them? They were his friends, too. The three of them got on so well, it was natural for them to occur to her. All three together made 'the boys', despite Castle's wealth and large number of friends. Sometimes she had to remind herself that he wasn't just a normal cop in her team with a modest number of acquaintances.

"How do I know they weren't the ones that ran it for her?" he continued obliviously.

Oh. So he had considered them. Of course he did, she shook her head.

"So, any ideas?" his eyebrows jovially high.

"Uh," she hummed, unable to even guess at the range of his social network.

He looked at her hopefully, but she was drawing a blank. When she didn't reply, his face fell slightly and the line of his shoulders slumped a little.

"Yeah," he sighed. "Sorry."

"It's fine."

"No, I'm going to make you late for your date."

"Castle," she scoffed. "I'm not about to throw you out. I have about a half hour, so here's my compromise: You make me a drink and keep thinking, and I'll get ready."

"Yeah?"

"Yeah," she smiled.

"Okay, great. Go," he fluttered his hands, shooing her away. "Go and get dressed."

Her eyebrows rose at his dismissal and he dropped his hands with a grin and a shrug. She turned and was almost at the threshold to her room before his call stopped her.

"Hey Beckett! Do you rent out the safe houses?"

She just shook her head and kept moving, her quiet chuckle not hidden by her retreating back.

…

"Beckett!" he hissed, skidding to a stop at her doorway. Half way through the process of pulling up her dress' zip, she froze. He seemed equally stunned, the swallowing movements in his throat clearly visible.

"Castle!" she choked.

He blinked and stumbled for her. "She's here," he sounded strangled. "I checked through the peephole and it's her."

"You answered my door?!" she exclaimed, hearing the sharp knock she must have missed the first time.

"No, I just checked to see who it was," he explained hurriedly shoving her iPod at her and crouching behind the far side of her bed. "Tell her you were listening to music," he called hoarsely.

"Castle!"

"Get the door!" he hissed, hidden from view.

She glared at him and hurried over to her door, feet bare and the back of her dress still not fully fastened. When she got within a few feet she heard a metallic scraping and she snatched at the locks. Natalie Rhodes was not breaking into her apartment.

To her credit, Natalie looked perfectly poised, greeting her with no more than a beaming smile when she got the door open. "Detective Beckett!"

"Natalie."

"Don't you just look stunning?" the actress' eyes roved the detective before stepping into the apartment and circling her. "Ah," she exclaimed. "Missed a spot," her hands drew the rest of the zip up without warning and Kate fought a flinch.

"Can I help you, Natalie?"

"Oh, don't mind me," Natalie threw over her shoulder, moving further into the apartment and looking it over carefully. When she caught sight of the two cups of coffee sitting on the kitchen island she turned to give Kate a scrutinizing look.

"Company already?" she asked, looking between the two cups of ready coffee and Kate's bare feet and temporary, un-styled messy bun.

"My boyfriend is due soon, it's for him," Kate improvised. "And I'm running a little behind."

"I didn't know you had a boyfriend. Is he tall?"

"Yes," Kate answered, unsure where this line of questioning was going.

"Dark?"

"Yes."

"Talented fingers?" Natalie asked archly, skipping the traditional third qualifier and catching her off guard.

Kate couldn't keep her composure and felt a blush heating her cheeks.

"Come on, Kate," Natalie wheedled. "What's a little chat between girls?"

Kate still made no move to answer, acutely aware that Castle was eavesdropping intently from the next room.

"From the look on your face, I'm going to have to take that as a 'yes'," Natalie smirked. "You know, I thought he would be. One look at him and I could see that, and of course he uses his hands all day."

Kate looked at her in confusion. "One look?" she asked. She just said she didn't even know I had a boyfriend, Kate frowned.

"Sure," Natalie breezed on. "Do you mind?" she gestured to the coffee and Kate could only dumbly shake her head quickly. "It's just going cold, and no one drinks lukewarm coffee."

The actress cradled it in her palms and stared at the painting dominating Kate's living room. Almost absently she took the first sip and immediately dropped her eyes to the mug.

"This one's yours," she passed it to Kate, doubling back to the kitchen and picking up the cup Castle had prepared for himself. She cautiously took a sip as Kate tried to reign in her resentment; Natalie shouldn't know what her coffee tasted like, the java thief. It was their coffee…her coffee.

The sly smile pulling at Natalie's face stopped the mutinous recollection and kicked the nerves in her belly into action. Oh God, what now?

"It tastes like Rick," the actress grinned.

"What?"

"Cream and two sugars," Nikki shrugged, still smug. "Just the way I like it."

Castle wasn't kidding, Natalie wasn't pulling any punches.

"You know, I don't know why you two don't just come out," Natalie tossed casually over her shoulder, browsing the titles in Kate's bookcase.

"I'm sorry?"

"You and Castle."

Is that was she was getting at? Tall, dark, talented fingers from typing. "That is not Castle's coffee. Castle is not my boyfriend," Kate enunciated very clearly, hoping to get through to this woman.

"Kate," Natalie chided.

"I have a boyfriend," Kate said. "He's a surgeon."

"Ooh," Natalie drew her shoulders up around her ears and pouted her lips, clearly not believing her.

"And Castle has a girlfriend."

"I know, I ran his background at the precinct."

Kate's mouth dropped.

"It was a test," the actress explained airily. "I told you I was going to do you better than you. No one caught on that it wasn't you at your desk."

"You did a background check on Castle?" Kate repeated, trying to comprehend it. "On my computer."

"And financials," Natalie beamed, obviously proud of herself. "He's been hiding from me, so I had to get a location. He had checked into the hotel, but I just flashed my badge and the staff let me right on up. I just can't believe I lost him," she shook her head in disappointment. "Anyway, I talked to Gina, his ex-wife, and she said that if he was hiding anywhere, you'd be the person to ask, so here I am."

"You talked to Gina," Kate stated. "And she didn't care that you were looking for him?"

"No, she said it was a great idea for the actors and the author to talk. Besides, from what I could tell, they aren't on very good terms. They've been fighting a lot."

There was a nervous flutter in her stomach at the news, but she breathed through it, going for unaffected. "I'm sorry to hear that, but I really don't think I can help you."

"You two have something, and he's clearly not in it with Gina. You must have an idea where he is," the actress pushed, shaking the mug slightly for emphasis.

"Have you tried Detective Esposito?" Kate tried to sidestep.

"He said Rick was probably here."

Kate grit her teeth. Bloody Esposito, so much for team loyalty. Or what was it? Bros before Hoes?

"I'm afraid I'm not very well acquainted with the majority of Castle's acquaintances. There are probably hundreds of houses and apartments he could be."

Natalie huffed out a frustrated breath, obviously ceding to Kate's point.

"If I can ask," Kate cleared her throat. "I thought you were only interested in Castle for, uh, research."

"Oh no, I did my research."

"What?"

"Oh, not like that," Natalie reassured her. "Yet. No I'm not really interested in just the research side of it anymore. He's actually pretty interesting."

She felt insulted on his behalf. Pretty interesting? Richard Castle, 'pretty interesting'?

"I thought it was a lost cause after he put me down the other night, but you assure me he's straight, so I put my new skills to use and did some digging. You'd be so proud of me, the people down in records and at the paper didn't know the difference between us at all. Looks like I've successfully mastered the ways of Beckett."

Kate felt her eyes bugging out. She used her acting to pull official files?

"He has a pretty cool history, actually. I found some pretty nice shots of him on the net," she added. "Does he work out with you too? From the art shots at his arrest, he definitely does something. Naked in March and I couldn't even tell."

Kate felt her face flushing. It was so strange to think about Castle as a piece of meat.

"I never asked you about that actually," Natalie recalled, the sly look on her face fading abruptly to her intent, 'researching' face. "What is your work out routine like? Can you really do all the things Rick wrote in his book?"

Despite the way 'Rick' grated on her, she was relieved to be back into safe territory. "I do aerobic exercise four times a week with anaerobic weights and sparring twice a week. Often it's hard to squeeze in with cases, meaning a lot of early mornings but sometimes though, it's just a good release after being in the box, or when we get a string of dead ends."

"And does your trainer have any special privileges?"

"No," Kate said emphatically. "That was all Castle's imagination. I've never done anything like that."

"Because you have a boyfriend?" Natalie pushed.

"No," Kate shook her head. "I've always thought defending yourself or trying to injure another is more than enough of a workout with my trainers."

Natalie opened her mouth to ask another question, but Kate cut her off. "Look Natalie, I don't mean to be rude, but I really have to finish getting ready, so…" she swept her hand towards the door.

"Does that mean I can have your coffee? I think I like yours more after all."

…

Will update soon as I've almost finished, I just had to split it for length purposes.

Let me know what you thought as I have some other oneshots based on old episodes I'm working on and would like to know if there is any interest.