A/N: This is my first Castle fanfic, which I find really hard to believe. I'm a total Castle groupie, and Richard Castle and Kate Beckett are the completion of my life. Thoughts of Caskett are never not on my mind ;D This is just a one-shot, but I hope you enjoy it (: xoxo

Lost Without You

He hated being worried about her.

It wasn't often that he had to worry about her; Kate Beckett could certainly take care of herself. She was a strong, independent woman who could handle just about anything.

At least, that was what Castle kept mentally telling himself as he silently cursed out the mid-day New York City traffic. The thickness of the air in the cab was making him uncomfortable, and he had a sick feeling in the pit of his stomach. Castle tried to put his mind at ease, but his instincts were telling him that something was wrong.

'Right, because we all know how accurate your instincts are.' A small chuckle escaped Castle's lips as he imagined Kate's retort to his thoughts.

'She's fine, I'm worrying for nothing. She's probably napping or something, and I'm about to disturb her and piss her off,' thought Castle. But he still could not completely chase away the gnawing feeling in his gut that something was wrong. It wasn't like one of his and Beckett's cases that he could explain through fact and reason…it was just a feeling, but Castle couldn't dismiss it.

'I'll just check in on her quick, make sure everything's alright, and then leave. Easy-peasy-lemon-squeezy.'

"Sir," started the thick-accented cab driver, interrupting Castle's thoughts, "it seems that there is an accident up ahead, this could take a while."

Castle glanced outside the window, and realizing that they had barely moved a dozen yards in the past 15 minutes, quickly threw the driver a twenty, the first bill he grabbed out of his pocket, and stepped out of the cab, signaling for him to keep the change.

Castle set a brisk pace along the city pavement towards Kate's apartment. He suddenly got an odd sense of déjà vu; the last time he had been in a rush to get to Kate's apartment, it was to try and save her life.

Castle suddenly started walking a whole lot faster.

Before he knew it, Castle was sprinting down the streets, his feet pounding on the ground as he tried to dodge the various people, dogs, and street vendors, his mind solely set on getting to Kate's apartment as soon as humanly possible. 'If there was ever a time for my super hero powers to kick in…'

The heat from the mid-afternoon sun was causing beads of perspiration to form on Castle's forehead. He quickly swiped away the moisture with the back of his hand, never once breaking his stamina the whole way.

Once he reached Kate's building and stepped inside the elevator, the adrenaline started to wear off and he found himself heaving for air.

In retrospect, he had just raved like a mad man through the city…and for what? Castle suddenly felt foolish as the elevator dinged and stopped on Kate's floor. If something was wrong, Kate would've called him, not turn her phone off…

Regardless of his thoughts, Castle walked up to Kate's apartment door and called her name as he knocked lightly. 'Please don't be mad that I'm here…'

After a few moments of no reply to his knocking, Castle was about to knock again until the door opened up a sliver. "Castle?"

The way she said his name scared him. She said it so quiet, almost fearfully…no, vulnerably, and Kate Beckett was not vulnerable.

"Kate? Are you ok?"

It was awkward talking to her so closely when he couldn't see her, as she still hadn't opened the door any more than a crack. "What are you doing here?" she asked, dismissing his question.

"I…I don't know, really. I was just worried. You didn't answer any of my calls yesterday, and the guys at the precinct hadn't seen or heard from you, and then your cell's been off since this morning. If you just need some space of whatever, that's fine…I just had a feeling that something was wrong. A stupid feeling. I'll just, uhm, go…sorry."

Castle turned to leave, mentally slapping himself for coming all the way here. Wasn't Kate allowed to have a day or two to unwind and relax? Why couldn't he respect that? 'Oh God, I'm becoming that needy person in the relationship who calls every 10 minutes to make sure the other is alright.'

The door suddenly creaked open, and Castle turned around to see her facial expression, which was probably either pissed, amused, or a combination of both. Most likely pissed. And it's not like he could blame her.

But that wasn't what Castle saw when he looked at her. He saw puffy red-rimmed eyes with fresh tears glistening on her eye lashes. She had sweat pants and an over sized t-shirt on, and it looked like it was taking a toll on her just to hold herself upright.

She looked…broken.

Castle was at a loss for words. He quickly walked back to her and put his hands on either side of her face. Tears began to slowly run down her cheeks, and he wrapped his arms tightly around her, trying to comfort her in any way possible.

"Oh Kate…shh…it's okay…I'm right here…" he gently soothed her. He ran his hands up and down her back, letting her feel him, letting her know he was there for her.

Suddenly aware of the fact that they were still standing in the dingy apartment hallway, Castle led them inside the doorway, his arm remaining wrapped around her waist. They made their way over to the couch together, and Castle helped Kate to gently sit down. He sat down as well, leaning against the arm rest and pulling Kate onto his lap and holding her close, letting her bury her face into his chest.

Castle was absolutely speechless. He had not seen this woman cry since the man who had killed her mother died as she tried so desperately to keep it from happening. Kate Beckett was the strongest person he knew, and he had no idea how to help her. Hell, he didn't even know what the heck was wrong. Thinking about the possibilities sure did scare him, though.

He tried to push his pessimistic thoughts away, instead just focusing on drawing soothing circles on Kate's back with his hands, trying to comfort her in any way he could as her body continued to be wracked with sobs. He could feel the moisture from her tears staining his shirt; he reached his hand up to skim it along the soft skin of her cheek, brushing away some of the tears. But no matter what he did, they just continued to fall.

Her tears eventually started to cease as her sobs turned into hiccups. Castle gently removed his arms from around her body, letting her pull back from him and wipe her face. He reached over the night stand and grabbed the box of tissues that was there, placing it in Kate's hands. She blotted at her face and sighed. She was a mess.

She leaned back and let her head fall back against the couch, to physically and emotionally exhausted to hold any of her weight up. She let her eyes close, and suddenly felt Castle's hands on her, one rubbing her right shoulder as the other caressed her thigh. And for a few minutes, she just let herself melt away under his touch; she kept her eyes closed and her mouth shut, and just let everything drift away for the first time that day.

After a while she opened her eyes, and was met with Castle's intent gaze. She shied away from it a bit, not yet ready to face explaining everything to him. She still could not believe she had just cried in front of him.

Castle, God bless him, remained silent as she tried to sort her thoughts out. She was extremely grateful; she knew how hard it was for him to keep quiet. She smiled a bit at this, which didn't go unnoticed by Castle.

Kate moved back over towards Castle on the couch, letting her back cradle against his chest. Castle instinctively held his hands at her hips, and enveloped her lower half with his outstretched legs. Kate felt better now that she was in his arms again; he made her feel safe.

"Thank you, Castle," she whispered quietly, her voice still raspy and strained from all the crying she had been doing that day.

"Of course," Castle whispered back. Kate felt stabs of pain pierce her heart at the tone of his voice. Now he was the one who sounded broken.

"Are you all right?"

"Am…am I alright? Jesus Kate. My concern here is whether or not you're alright."

When Kate didn't respond to this, Castle's heart beat got a little bit faster.

"Kate…" he started.

No response.

"Kate…you know you can tell me anything, right? Anything at all? I'm always here for you…you know that, don't you?"

As cliché as it sounded, Castle meant every word he said. They had only technically been "together" for about four months now, but he was more in love with her than he had ever been with anyone in his entire life.

Kate still didn't verbally respond, but she did nod slightly, which at this point was good enough for him.

"This day just…it's the one day that never gets easier."

Castle had no idea what exactly what she was referring to, but she had finally started talking, and he didn't want her to stop. So he sat there silently, waiting for her to continue when she was ready.

"Ya know, every year, it gets a bit easier to deal with. But this day…it just gets harder. It's like all the feelings I hold in come pouring out in one 24 hour time-slot."

Castle was starting to get an idea about what was going on. But he wanted her to say it.

"What day, Kate?"

The clock ticking in the corner of the room suddenly shrilled as the hour hand hit the four. The blaring noises from the outside world seemed to stop. Everything in the apartment was absolutely still, the slight breeze that had been rustling the drawn curtains ceasing, as if everything around them was holding its breath.

"My mom's birthday," she whispered softly, almost inaudibly. It felt strange coming from her lips. She hadn't talked about this with anyone in years. Her dad always called her on this day, but they never actually talked about what the day was, and what it meant. They would talk about the weather or the score of the baseball game from the previous night. But never what was truly on their minds.

Kate felt good about saying it out loud, being able to talk about it was new for her. Words suddenly starting spilling from her lips, and she was unable to stop them.

"I...I never talk about this day. Not even my dad. When I went to therapy shortly after…I never talked about it with my therapist either. Her birthday was always so special. When I was young me and my dad would get up early to make her breakfast in bed, and I always stayed up late the night before gluing macaroni to construction paper, or googly eyes on drawings. Mom always appreciated the sentimental value of things. When I got older, we found new ways to celebrate. We'd drive down to the Jersey shore for the day, or spend the entire day shopping until we couldn't walk another step. One time, her birthday fell on the night I was supposed to go to Homecoming. All my friends were going and we were supposed to all go together. My mom said that she didn't mind at all, that I should go and have a great time. But the day before I backed out. It just didn't feel right to spend the day without her…it still doesn't."

Kate sighed in relief, but tears still pricked at her eyes. But God, it felt so damn good to finally get all this out, to finally be able to talk about it with someone.

Kate was still cradled against Castle's chest. She turned in his arms so that she was facing him, and stared right into his eyes. She saw tears glistening there, and brought her finger up to his cheek to wipe one away that had trickled down.

"What are you thinking?" she asked him curiously.

"I'm…I'm thinking about how much I love you. And how sorry I am that you have to go through this. I hate it."

"I hate it to."

Castle reached his arms up and wrapped them around her back, pressing her down so she lay flat against him, not knowing what else to do. Kate sighed as she relaxed in his arms.

"Thank you, Castle."

"For what?"

"For being here. For caring. You have no idea how much I appreciate it."

He smiled up at her. "Of course. I'm always here for you, Kate. I'm sorry there's nothing more I can do to help."

"Oh, Castle, trust me, you've done more than enough…I love you. So much."

"I love you too."

And with that, Kate brought her lips down to meet his in an almost agonizingly slow kiss. Castle reached up and tucked a few loose strands of hair behind her ear once they had pulled away for air. She grinned before kissing him again, happy on her mom's birthday for the first time in years. And all because the man she was hopelessly in love with had a feeling.

'I can't believe the man who's instincts usually lead to theories of a time traveling killer was actually right.'

Kate couldn't help but giggle at this thought.

"What's so funny?"

"Oh…nothing…"

A/N: Hope you liked it! (: Since their officially in a relationship in this, that's obviously why I had Castle call her Kate and not Beckett, and it felt really comfortable writing it that way…but I just could not bring myself to have Kate call him Richard or Rick or anything that's not Castle. It just…doesn't feel right to me. Haha, I don't know. But anyways, really hope y'all enjoyed, and I would LOVE if you would leave a review (: But I love all my Castle groupies, so even if you don't review, I'm really grateful to anyone who even took the time to read this (: But anyone who does review will get Caskett cupcakes ^_^ Just throwin' that out there…

You can definitely expect more Castle fics from me in the future, by the way (: If you have any requests for a Castle Fanfic, feel free to PM me! (: