Anonymous Prompt: PreCaskett, Castle sees Beckett out with a man and gets jealous - only to later on find out (much to Beckett's amusement when she realizes he's jealous) that the man is her cousin/brother/whatever

Takes place sometime between The Dead Pool and Always.

Kate typed case notes into her computer, almost finished with the document, when she felt it. That familiar and annoying tingling at the back of her neck.

"Castle," she said, "Do I have to pull my gun on you to make you stop staring?"

She turned, and he was still looking at her, but there was something different than the usual twinkle in his eyes. "I don't know, but you could definitely try it and see," he replied.

Castle looked away as she rolled her eyes. He really could be trying at times.

"So..." he started, then let the word hang for a time.

Kate saved the document and turned away from the computer. "So, what?" she asked, knowing he was probably about to ask some infuriating question in 'the spirit of research.'

"I saw you when I went to Borders last night..."

"You were stalking me?!" she asked, surprised, yet teasing him a little. Yeah, she was there, and she wasn't alone. Kate had a feeling where this conversation was about to lead.

He seemed surprised at her reaction. "Stalking? No! I wouldn't do that! I actually went there to find a replacement copy for one of my books. - Not one of my books - but another book... one that I own that I didn't write."

He was stumbling all over his words, and it almost made her laugh. "Okay, then tell me what you were doing there. You know I do actually have to work today and don't have time to decipher whatever it is you're trying to ask me." Kate wasn't really in a hurry to get back to the paperwork, but she wasn't going to spend all day dancing around the subject.

"All right," he said, then took a deep breath. "I saw you weren't alone..."

"No, I wasn't," she confirmed. Her writer was getting jealous again. "So?"

"So? So... does he have a name?"

It was killing him, dragging this out. "Yeah, he does." She leaned toward him a little, resting her chin in her hand. "Would you like to know his name, Castle?"

He shrugged, trying to look uninterested. "Only if you want-"

"Robert."

"Okay, so, this Robert... tell me about him. You two seemed pretty close."

"Oh yeah, Castle," she smiled and sighed, pulling him into the story she was about to spin for him. "He really is something. This is the second time we've gone out this week."

"Sec-" he almost squeaked, then cleared his throat and tried again. "Second time this week? Sounds serious."

"It could be," she answered, really enjoying how he was trying to hold back his jealousy. After the issue with Conrad, she found him cute like this. "In fact, we're going out again tonight."

"W-wow, that is something. A lot of time together in just a week."

"Yeah, it is. But, he's a lot of fun to be around, laughs a lot, and we get along really well."

Kate was pretty sure she could see a little bit of disappointment in his eyes. He still didn't get it, but maybe she was still figuring all this out as well. With a sigh, she decided she had tortured him enough for one day.

"His name is Robert Beckett. My cousin. It's the first time he's been back to the city in ten years, and he's staying with me for a few days."

"OH-oh! Okay, your cousin." He seemed genuinely relieved. "That's good to know."

"You're still an easy mark, Castle," she smiled and rolled her eyes, "I took him to the bookstore last night because he was interested in reading your books. He wouldn't stop talking about everything my Aunt Theresa told him about you shadowing me. So, I got him started on the Storm series."

"Really?" He was like a kid at Christmas. "That's awesome!"

"Yeah," she said, waving him off, trying to make it look like she was making light of it. "I had to shut him up somehow, and it seemed to work really well."

"Very funny, Beckett," he smirked, "But I have to ask, why didn't you go with Heat Wave?"

Kate gave him the look. That wasn't the most intelligent question he could have asked.

"Yeah, that would be kind of awkward," he admitted after a moment. "Besides, Derrick Storm was my first real series. It's a good starting point."

"Thank you," she said. Her phone chirped with a text message. She took a moment to read it, then looked back at Castle. "And it looks like you've got another fan. He wants to meet you."

His eyes sparkled a little more, like he had just received a present. "I bet I could fit him into my schedule. When would be a good time?"

"Well, he leaves out in the morning," she said, then took a second to calm her nerves. "How about dinner tonight at my place? Be there at seven?"

When he smiled this time, there was something a little different about it, and it made her feel warm all over. "That would be great."