It had been a week since Castle opened up to Beckett. And everyday since Castle had shut her out even more than the first day. Kate was studying him beyond the basics, beyond what any stranger could find themselves. She was studying the inside of Detective Richard Castle, what made him tick. And everyday she found herself more and more interested in him.

Castle knew that Beckett was staring at him while he did his paperwork. The first minute or so he tried to ignore it, but than the stare began to feel like it was drilling holes through him.

"What do you want?" Castle snapped.

"Nothing…"

Castle returned to his work, and again he felt her staring at him. This time he didn't even bother to look up. "You're staring again!"

"I'm researching." Beckett answered continuing to openly stare at him.

"Doesn't research involve things like a paper and pencil? You don't seem to have any of those things." The bitterness in his voice could be felt miles away, but Beckett just pushed it aside.

"No, no, not that type of research." Beckett laughed, "I'm doing my own personal research."

"Go personally research Ryan or Esposito. I'm sure they won't mind."

Castle was trying to dismiss her, trying to make her leave, but Beckett didn't make a move. It always infuriated Castle how she never listened. He'd say: Don't touch that… and it was like she was than forced to touch it. She was a child that he constantly had to watch over.

"You're still here…" Castle said finally glancing up from his work.

Beckett looked around the precinct, "I didn't realize you asked me to leave."

Of course she didn't notice, Castle thought. Even if he flat out asked her to leave she still wouldn't notice. Not saying that Kate Beckett wasn't smart, because she certainly was. Over the past week, Castle had done some personal research of his own, but from afar of course. She was brilliant, she thought in ways that stunned Castle himself. The most mind blowing thing she had done was the when she profiled him so fast that first day.

Castle had to refocus; he was letting himself think too much about her. Every so often he would find himself slipping and letting his mind wander off to think about her. And when those moments happened he would push it all away and become cold again, refusing to let her see any more inside of him.

"So what are we doing today detective?" Beckett asked happily.

"Paperwork." Castle said flatly.

Beckett whined and groaned, "We did paperwork yesterday though!"

"I'm sorry that this isn't the crime fighting action packed job you signed up for." Castle went back to his paperwork, hoping to signal that it was the end of their conversation. But knowing Beckett, she'd keep going.

Beckett sat quiet in thought for a few moments, which almost stunned Castle. But before the moment could become too perfect, Beckett shot her hand out and stole Castle's pen.

Castle glared at her and she smiled at her accomplishment. "Give me back my pen," he demanded.

"Nope." Beckett pushed her chair back and calmly walked away.

"Breathe." Castle tried to tell himself. He looked around his desk hoping he could find another pen. And of course, the one day he does not have an extra pen! He groaned just thinking about what he was going to have to endure to get his pen back.

Richard walked over to his partner's desks. "Have you guys seen Beckett?"

Esposito and Ryan looked at each other with a wondering glance. "I think she made off towards the interrogation room," Esposito replied smoothly.

"Yeah and she was twirling a pen around in her hand all happy and smiling," Ryan added.

Castle groaned internally and nodded at them as he headed off towards the interrogation room.

Looking through the mirror, he could see Beckett smiling and sitting in the chair facing the mirror. Castle took another breath and walked into the room.

"So this is what a murderer feels like, having to sit in this chair. I find it quite relaxing." Beckett joked trying to lighten up the mood.

"Give me my pen back." Castle ignored her joke completely.

"Ah, so you are going to play bad cop. That figures because you aren't very nice to begin with." Beckett rambled on and Castle was starting to lose his patience.

"Give me my pen back." Castle repeated himself.

"Does that mean Esposito is good cop? No, I think Ryan is good cop. Ryan is a big softy." Beckett continued without even acknowledging Castle's request.

He knew that he was playing her game, and he knew that was exactly what she wanted. Castle knew that there was a whole precinct of people and surely one of them would have a pen he could borrow, but he wanted his pen, the pen Beckett was twirling in her fingers.

He gave her one last glare, ready to give up and ask a cop for their pen. Beckett stopped twirling the pen and looked at him.

"Oh this pen…" Beckett teased him. "I actually like this pen quite a lot; I might keep it in fact," than she went back to dancing the pen around her fingers.

Castle felt her pushing all of his buttons. He would never understand how she could possibly find the little things that aggravated him; and than he snapped.

"Why do you have to be such a child? Why can't you grow up and be a normal adult like the rest of the world?" He snapped.

Kate stared at him wide eyed. She was hoping he would just give up and find someone else's pen, she never thought he would last this long.

Than the realization of what he actually just said to Beckett hit him. He didn't know what to say, he wasn't good at saying sorry. So he just stared at her as she stared back at him.

"You aren't… I meant…" Castle stumbled on his words as Beckett tried to not let him see the hurt she felt. And when the guilt became too much for Castle, he left.

Beckett watched as Castle disappeared through the door. She knew she was being childish. She was just trying to let Castle loosen up a bit. He was always so uptight, but Beckett should have respected that. Richard Castle has a very hard job and he is respected by many in New York, of course he has no time to be childish, of course he always has to be serious. Beckett should have realized that.

She stood slowly and checked herself in the mirror, to make sure she looked as strong as possible, just in case Castle had planned for a round two. Taking a breath she opened the door back out into the precinct…

Castle hoped that Beckett would come back to his desk so he could formally apologize. Nobody deserved what he did to her. But she had left. He didn't even catch a glimpse of her. When he asked around the precinct, whoever had seen her told him that she said she was going home. Castle couldn't get any paper work done for the rest of the day because he couldn't get his mind off what he had said. Rick had made plans that first thing tomorrow he would apologize to her, and than hopefully she wouldn't speak of it again.

He felt a little better after he arrived home to his daughter, Alexis, cooking pasta. It always made Castle wonder how she learned to cook so good when he himself was a terrible cook. Normally he would order take out on the way home or eating Alexis's amazing cooking.

"Hi dad," she said with a smile "how was work? Did you catch any bad guys?"

Alexis Castle looked nothing like her father. Her hair was a beautiful shade of strawberry blonde, but leaning more towards red, which she got from her grandmother and she had bright blue eyes, which she inherited from her father. Besides appearance, Richard and his daughter were quite alike. They both were very smart; Alexis more book smart than Castle though. It would shock many, but Richard Castle use to have fun and he wasn't always this uptight and serious. But after years working his job and his brother's murder, he closed himself off from the world.

"Nope, it was only desk work that was done today. Sorry to disappoint you." Castle said while he grabbed plates from the cabinet to set out for dinner.

"Sounds like a very exciting day."

Castle was than reminded of the pen indecent in the Integration room and he was suddenly overwhelmed with guilt again.

"Where is the old lady?" Castle asked.

"I heard that!" Martha Rodgers announced as she gracefully made her grand entrance down the steps. "And I'll have you know some old friends from a musical I did back when I was young told me I didn't look a day over forty!"

"Are those the same friends that told you to sleep with the casting director to get a part?" Castle joked with his mother.

"Which I never ended up doing! Do not worry Alexis, dear; I was much smarter than they thought! And I still ended up with the part!"

"She claims that she never-" Castle paused when he heard the sudden knocks at the door. "Alexis… Did you invite anyone over for dinner?" He asked.

"I don't think so."

Castle walked to the door and looked through the peephole, standing there with a basket at hand was Beckett staring down at her feet while she shifted nervously back and forth.

Beckett glanced up as soon as she heard the door unlock, and suddenly all of the butterflies she was trying to ignore were fluttering around in her stomach.

"Uh Detective Castle, I'm sorry I know it's dinner time and you are probably eating right now. I got your address from Ryan and Esposito, so I am not a stalker I promise. I was just here to-" Beckett paused and than shoved the basket towards Castle after realizing she wasn't good at talking.

"Who's at the door?" A voice from inside called, than a girl around the age of 16 popped her head out from behind Castle.

"Uh, hi… I'm Kate Beckett. I'm the writer that's been shadowing Castle for the past week." Beckett stuck her hand out towards the red haired girl.

"Hi. I'm Alexis." She said as she shook hands with the writer. "My dad did mention that you had been shadowing him."

"Dad?" Beckett asked puzzled, "I wasn't aware that you had a-"

"So what are you doing here?" Castle cut in before Beckett could finish.

"Oh, um… Well I felt bad for what happened today. So I brought you these," she motioned towards the basket which was full of the same exact pen that she had stolen from him early in the day. "I know that I act like a child, and I'm sorry that I made you angry. It won't happen again, I promise."

Castle didn't know what to say, so he just stood there with Beckett and his daughter in the doorway of his apartment with a basketful of pens.

Alexis sensed the awkwardness between the two so she decided to help. "Why don't you stay for dinner Miss. Beckett?"

"You can call me Kate," Beckett smiled at the youngest Castle. "And I really have to get going, thank you for the offer though. I'm sorry once again." She said with one last glance at Castle.

Another moment of silence, than Kate nodded and headed off down the hallway. Castle closed the door and Alexis was smiling at him.

"I like her, she's nice."

Castle just shook his head and sat down at the table for dinner.