AN: Sorry for the late update! But I hope you enjoy it. Thank you all for putting this story in your favorites/ tracking the story. :)

Kathie arrived at Kate's apartment after having a bit of a problem getting a cab. She looked around when she placed her things down and smiled, it was definitely Kate's style. She hadn't changed much over the few years they were distant.

Kathie probably should of just gone to her apartment but it would of taken her more than an hour and she didn't feel like dealing with rush hour traffic and all the people on the subway. She loved New York, but she would also love it if it wasn't as crowded.

She laid down on the sofa and sighed. She turned her head towards the bookshelf Kate had and smiled when she spotted Castle's books. She wondered if she had told him about how special he really was to her. She could see it by just those few minutes she was there at the station that her sister cared deeply for this writer, something she couldn't see while they were just talking on the phone about his crazy theories and how he'd help her on cases. But knowing Kate she was too scared to admit that to herself and to him.

She looked up at the ceiling and wondered what her life would be like if she had accepted that FBI job instead of wanting to stay in New York to be close to her big sister and teach. Would she have caught their mother's killer long before tonight? She sighed and closed her eyes. "I hope you're proud of me mom and I promise I'll do whatever it takes to make sure I'm not joining you tonight and to make sure Kate is safe".

She sat up from the sofa and grabbed a notepad that was on the coffee table. She picked up the pen that was next to it and started writing.

XXX

Back at the station it was a little close to 8 now and Kate Beckett was sitting at her desk trying to get through this paper work as fast as she could. She wanted to get home and make sure Kathie was safe. That dream she had and Kathie just appearing without a reason was a sign that something was wrong. Granted her sister lived in the same state that she did now for the past few months so it was only a mater of time she would visit but she had a feeling the dream she had meant something more than just being a nightmare.

"Kate?" Castle's voice knocked her out of her trance for the second time that day. "Are you okay?"

"Yea, fine. Just tired of doing this paper work I guess" Another excuse. How many more of these could she come up with? "You know you don't have to stay here...unless you were planning on chipping in for once and do your fair share" She smirked, hoping he'd avoid asking her what was wrong yet again.

"No no. I wouldn't want you to share all the privileges of your job with me. I'll let you keep this one for yourself" She rolled her eyes as she saw him smile. "But I will go get us some coffee". He got up and headed into the break room to start up the cappuccino machine.

He knew something was wrong with his Kate...wait did he just say his Kate? She wasn't his...but he wished she was. He knew some day soon that wish would be reality. He looked at her through the glass window and sighed as he saw her go into a trance yet again. She was either really coffee deprived or her sister visiting really had an effect on her and she wasn't letting him know.

They seemed fine, better than most sister's usually act when they're around each other. So what was the problem then? What wasn't she sharing with him?

As he exited the break room with their coffee's he saw the elevator's doors open and out stepped a delivery boy. "Kate Beckett?"

Kate and Castle both looked confused. She didn't order anything. "Yes, that's me".

"Your sister wanted to send over some sub sandwiches for the night shift". Kate smiled. Kathie hadn't changed a bit. It was weird that they took turns being the older sister. Kate would be there to comfort her and give her advice when she needed but then Kathie would do something like making sure she ate to be the big sister for the moment. She went to pull money out of her pocket but the delivery boy stopped them. "It's already paid for". He smiled before heading back into the elevator.

"These are the moments I wish I wasn't an only child. A sister that buys me food is a keeper" Castle said as he opened up one of the styrofoam containers that was labeled C. He opened it up and smiled at the delicious meatball sub he saw. Kathie didn't even know him but yet she picked one of his favorites.

He went to move the container a bit in his hands when he felt something taped to the bottom of it. He didn't want to alarm Beckett, especially since she was smiling for the first time since her sister left the station. "Well they might of brought the food but the napkins seem to be not included". With that he got up with his container in his hand and headed back to the break room.

He closed the container and lifted it up slightly so he could see the bottom. There was an envelope attached to the container. She pulled it off and saw that it was addressed to him. It looked like a woman had written his name on the envelope. He looked over at Beckett, who was too busy enjoying her chicken avocado sub to notice. He placed the container down and opened the envelope. He unfolded the note that was inside and read it.

Dear Richard Castle,

If you're reading this now most likely I am dead. I know that Kate is in good hands thanks to you in her life. When she's ready to tell you how important you are to her you will be amazed about how much you mean to her and what you did to help her. As her sister I give you the sister approval of dating her, when that time comes of course. I was hoping to be there when it happened but it doesn't seem to be the case.

I remember the first day you walked into her life and she called me up for the first time in a few months, for us that's a long time. I didn't believe her when she told me she was working with you. Oh and yes, she did have a fangirl moment while telling me all of this.

Please take care of her. Don't let her get hurt. I love my sister and I hope she can understand that what I did tonight I had to do...for her and for our mother. This needs to come to an end. I wanted to tell her and leaving the station today was the hardest thing I ever had to do, knowing that I wasn't going to see her again. But I know with you in her life she will do great things, even with my absence.

My laptop is in her apartment by the door. It will tell you where my body is and it also has a letter to Kate. Please make her read it so she can understand. If she doesn't read it just make sure to tell her that I love her and that I'll be watching over her to make sure nothing happens.

Thank you,

Kathleen Beckett

He couldn't believe it. Kate's little sister was going to try and take down their mother's killer. He had to tell her. He looked at the clock and saw it was about twenty minutes after 8 Ryan and Esposito left about an hour ago so telling them wasn't an option. What was he going to do? He made sure to keep his findings a secret to protect Kate and now he had to deal with this. This was her sister and she knew if she found out about this she'd pick up the case again. A pair of heels startled him from behind.

"Don't tell her". Gates said as she walked into the break room to stand next to him.

"It's her sister..."

"She'll be fine...she's with Esposito and Ryan". She sighed. "I wasn't happy when I found out Ryan and Esposito were looking into this without my knowledge but as you know the Becketts...well they won't stop until they get what they're looking for".

Castle sighed and looked through the glass to look at Kate. He saw her staring at the both of them. "She'll know something is wrong".

"Not if you go home. If you don't think you're strong enough to hide this from her then you should leave, Mr. Castle". She walked out of the break room with a coffee cup in hand. She headed back to her office and shut the door. Kate came speed walking into the break room once Gates left.

"What was that about?" She asked curiously.

"Nothing, just saying that I should go home since no dead bodies have dropped" He looked down at the note once again before folding it up and placing it in his jacket pocket.

"What's that?" She knew Castle wasn't telling the whole truth. It was like Gates to say that to him but how he said it, like he thought going home was a good idea, is what alarmed her. He never liked to leave until she was ready to leave. One of the reasons why she cared for him so much. "God Kate stop that! We have to focus!" she thought.

"Nothing, just a to do list. Alexis said it will make me more organized so she doesn't have to answer the house phone to a very angry publisher when I forget my deadlines".

Kate smirked. "Well the first thing on that list should be to eat your sandwich before it gets cold. You're always after me to eat so I'm returning the favor now" She gave him a soft smile. Truth was she didn't want him to leave, even if she had suggested he go home before. If he was there and she zoned out again at least he could make sure she got home on time.

It broke his heart that she didn't know. But since Ryan and Esposito didn't show up there was still a chance Kathie was still alive... either that or all three of them were dead. He hoped it was the first one.

"That's what makes you an amazing partner" He smiled before picking up the one half of the sub and taking a bite.