Author's note: Hi everyone. I apologize for having been so quiet the last couple of months. Personal problems and work have kept me away. Anyhow, I've had this idea running in my head for a couple of days so I finally took some time to myself to try and write it down for you.

It's supposed to happen during 6x12 "Deep Cover". Pure speculation on my part and since the episode won't air until Monday (Tuesday for me on iTunes since I'm in Europe), possible spoilers are entirely coincidental. I do hope you will enjoy your reading though. If you feel like it, please leave me a word to tell me what you thought about it.
Please remember English is my third language and I'm my own editor. :-)

And, of course, "Castle" belongs to ABC and Andrew Marlowe and Co.

Kate Beckett was no fool.

She had known something was out of place the second they had discovered that their latest suspect was a former CIA operative. At that very moment, no enthusiastic comment or crazy theory had made it past the lips of her usually extremely talkative partner.
Instead, he had kept uncharacteristically quiet and had resumed staring at the two sketches on her murder board as if he were seeing through them, seeing something she could not.

Even though she was curious and just a little bit worried about him, she had chosen to let the matter go for a while, had made a note to ask him about it later on that day.

Then she had actually met Mr. Anderson Cross. Or rather, she had met the man who liked to call himself that way. She had a distinct feeling the name was fake.
Kate was not sure what to make of that man. Anderson Cross was certainly handsome for a man of his age – there was no doubting it – but the way he flirted with her – and sometimes in front of Castle himself, no less – made her feel slightly uneasy.
Not to mention there was something oddly familiar about him, even though she couldn't quite put her finger on it.

It turned out Anderson Cross had not listened to her recommendations. The man was nowhere to be found, which meant that on top of the homicide she had to solve, she also needed to discover where he was currently hiding.

As the investigation went on, Kate could not help but notice how Castle seemed to be more and more on edge. The day before, he had even declined her invitation to go to her place so they could have some quiet alone and quality time together. He had stated he needed to get some writing done, told her he loved and kissed her good night and then simply left.
She could feel figurative walls rise around him, not unlike the ones he had managed to break through. He was shutting everyone out, and she realized she had no choice but to confront him about it.

She picked up her phone and was just about to call her fiancé when Ryan, looking every bit like he was on the verge of delivering the worst news of the year, handed her the address where Anderson Cross seemed to have been seen.

She felt her heart miss a couple of beats when the information registered in her brain. She so deeply wanted to deny what her eyes were seeing. She could not. So she picked up her coat and headed straight away to Castle's loft.

Given the circumstances, she knocked on the door, not wanting to use her key. Not even a minute passed by before Castle opened it with a smile that did not quite reach his eyes.

"Hey, Castle."

"Hey. I knew it was you. Recognized the way you knock."

"Of course you did."

He stepped aside, letting her come in. She took a quick look around the loft. Given the lack of noise, neither Martha nor Alexis were around. Good. She let Castle help her out of her coat before she turned around and looked at him expectantly.

"Where is he?" she firmly asked, wanting to clear this situation as fast as possible.

"Who are you talking about?"

Kate internally sighed and cursed at the same time. If he chose to pretend he didn't understand her question, she was afraid this was going to be a lot harder than she had expected.

"Rick. Please don't do this." she told him, slightly raising her voice to signal she meant business. "Anderson Cross. Where is he?"

"How should I know?"

"Because you are harboring him, Rick! You are harboring a fugitive! And don't you dare lie to me and pretend it's not true!"

Silence fell, heavy and uncomfortable. They both stared at each other for a long time, neither one wanting to back off. Ultimately, though, Castle sighed and lowered his gaze to the floor while his shoulders drooped in defeat. He still kept silent.
So, Kate decided to try another approach. Softening her features, she reached out to cup his cheek and make him look at her again.

"Castle, I am not here to press any charges against you or drag you at the precinct in cuffs. Ryan and I agreed to keep this silent as long as we could. I'm hoping we can keep it silent forever. But I know you wouldn't have done this without a reason. So please tell me. Tell me why you are giving shelter to that man. And tell me where he is now."

He sighed again, though this time it seemed it was to gather his resolve. Wordlessly, he took both of her hands in his own and caressed them gently with his thumbs.

"You're right. I'm sorry. I should never have kept this from you but I honestly did not feel like I had any choice. I –I just needed…" he trailed off, unsure of how to continue.

"What did you need, Castle?"

"Anderson Cross, aka Jackson Hunt, aka the man in the sketch…He's your future father-in-law."

Kate felt her knees go week and all the words she could have tried to enunciate instantly flew out of her head. She gaped at him, not even able to wrap her mind around the implications he had just formulated. The only thing that actually managed to leave her strangled throat was probably the quietest "What?" she had ever spoken in her life.

"He's my father, Kate." Castle went on, seemingly desperate to make her understand his point of view. "He's my father, and he asked me to help him. How could I refuse? He's –

"Your father?" she repeated, still not quite believing it. "God help me, Castle, how long have you known this? And why on Earth didn't you tell me?"

"I've known since Paris, last year. He's the one who helped me get Alexis back. As for why I did not tell you…I wanted to tell you, Kate, you have to believe me. I wanted to, but he forbade me to tell anyone. Not a single word. He said it could ruin his cover, and as a result put all of us in serious danger. He – He actually is the reason why Alexis was abducted in the first place. It was all about revenge."

"And you've been shouldering this on your own for almost a year?"

Before he could reply properly, a third voice resonated through the loft.

"Detective Beckett! How nice to see you again."

Upon hearing her name, Kate turned around to see Anderson Cross walk down the stairs that led to the first floor and the guest room. He was smiling from ear to ear, looking perfectly at ease, just as if he had been living there all of his life. All of Castle's life. That last thought made the blood in her veins start boiling.
Disengaging herself from Castle's arms, she took a couple of steps towards her supposed future father-in-law and watched with utter annoyance as he made himself at home, pouring himself a glass of wine and taking a seat on the couch.

"Mr. Anderson Cross, give me one good reason why I shouldn't arrest you for not having followed my instructions."

He had the nerve to chuckle.

"I am an intelligence asset for the United States of America, Detective. Do you really think you're in any position to give me instructions and expect me to follow them? If you do, then you're certainly not as bright as I thought you were. Coming to think of it, I expected you to come here earlier. What took you so long?"

Kate felt like strangling this man. How dare he insult her the way he did?! However, before she could get her hands around Anderson's neck – or whatever his real name was – Castle himself was placing himself between the both of them, looking just as angry as she did.

"You'd better take that back. She's my fiancée. She's the woman I love. I won't let anyone disrespect her. Not even you."

The man kept silent for a moment, obviously considering his options. Eventually, he gave a short nod in his son's direction.

"Fine. I'm sorry, Detective. Please accept my deepest apologies."

Kate could not help but snort at the obvious lack of sincerity of those words.
She was just about to reply when the door of the loft flew open and both Kate and Castle watched in horror as Martha made one of her typical dramatic entrances, completely unaware of what or rather who was awaiting her.

"Hello, darlings! Oh, you are not going to believe what happened today! I was at the studio when the one and only Luke Ruskin – you know, the famous playwright? – actually dropped by and asked me whether I would agree to bring his latest work on stage and co-direct it with –

The second the flamboyant woman's eyes spotted the man currently sitting on the couch, she stopped dead in her tracks. Kate absent-mindedly thought that if the older woman ever wanted to teach one of her acting students how to look when struck by lightning, the facial expression and stance she was currently displaying would be the ones to go for.
As for Castle, who stood by Kate's side as loyally as ever, he simply did not know what to do.

"You." Martha whispered, clearly not believing what she was seeing. "It's you."

"Hello, Martha." Anderson stated quietly as he rose up from where he had been sitting, looking suddenly much less confident than he did before. "You're looking as beautiful as ever."

Kate took a quick look at her partner. He watched, utterly enraptured by the scene before him, looking both incredibly hopeful and terribly scared at the same time and her heart broke for him a little when she realized this was the first time in his life he was seeing both of his parents in the same place at the same time. And she understood just how extremely important the next couple of minutes would be for him.
She reached for his hand, entwining her fingers with his own and squeezed them briefly to let him know she was right by his side, literally and figuratively.

And then all hell broke loose.

Kate could only watch in disbelief as, for the first time since she had met Castle's mother more than six years ago, Martha's eyes darkened with unmistakable fury. The actress took large, determined steps towards her former lover and to his credit, he did not waver under the force with which she slapped him across the face. Hard.

"HOW DARE YOU COME HERE AND ACT AS IF NOTHING HAPPENED?!"

She moved to slap him once more but this time, Anderson caught her wrist before her hand could connect with his cheek.

"I admit I deserved the first one." He stated calmly, his voice dangerously low. "But there won't be a second."

"Let. Me. Go. Right. Now."

"Of course." Anderson acknowledged as he slowly released his hold on Martha yet still managed to look quite threatening.

"What the HELL are you doing here?"

"I have some matters to take care of. And I needed somewhere to stay."

"So what?! You just decided that after more than FORTY YEARS of absence, now was the time to show up and check whether I managed to survive after you slept with me, told me you loved me, got me pregnant with our son and disappeared?!"

Kate internally cringed as she felt Rick's body stiffen beside her. She felt so sorry. He deserved so much more, so much better than the scene that was unfolding itself in front of them. She wished there was something she could do to help him but she didn't have any right to interrupt Martha for if she were in her future mother-in-law's position, she'd be just as furious.

"I couldn't stay with you, Martha." Anderson tried to explain, frustration and annoyance seeping onto his features. "But what I said was the truth. I did love you."

"Well, you sure had a strange way of showing it! Where were you when we needed help? Go on, tell me! Where were you when we struggled on a daily basis to make both ends meet? Where were you when I needed you, when OUR SON needed you?! WHERE WERE YOU when other kids his age told him he didn't have a father BECAUSE NO MAN WOULD WANT TO HAVE A BOY LIKE HIM and when he cried ALL NIGHT LONG because of it?!"

"Well, I'M SORRY but I could not jeopardize my career and everything I had worked so hard to obtain for the sake of a one-night stand and a boy whose life was and still is NOTHING BUT AN ACCIDENT!"

Silence fell again as soon as Anderson realized what he had just said, but it was too late. It was the proverbial straw that broke the camel's back. Kate sucked in a breath she did not know she had been holding and looked at her partner who was now shaking beside her whilst tears fought to escape from his eyes.
She could see his Adam apple bob painfully in his throat. The last time she had seen him look so hurt was when he'd discovered her boarding pass after she'd flown out to Washington D.C. for the interview.

"Is that all you see me as, Dad?" Castle whispered with difficulty, his voice slightly more high pitched than usual. In the silence, though, he might as well have shouted it from the rooftop. "Is that all I am to you? An accident?"

Anderson Cross had the good grace to look embarrassed, but he still kept silent.

"Oh, Richard." Martha started, also clearly affected by the palpable pain in her son's voice. "Darling -

"No, mother." Castle replied softly as he looked one last time at his father before he let go of Kate's hand and turned around, heading for the bedroom. "I believe I've heard enough. I'm going to take a shower and head to bed. You can finish what you started. It's not like you need me anyway."

Anderson, Martha and Kate could only watch as he closed the door behind him with a sense of finality and defeat that did not suit him at all. Kate herself felt like crying too, with him, for him, for the little boy Castle had once been and whose hopes had just been crushed by the one man who should never have done it.

And so, with a sense of mixed anger and disdain she hadn't felt in a long time, she turned towards Anderson Cross to look him in the eye.

"Well done. I hope you're proud of yourself. "

And she left him standing there in the living-room with Martha because that was not where she was the most needed.

She stepped into the bedroom, closed the door behind her and sadly eyed the clothes that were lying on the floor in a heap. The water was running in the en-suite bathroom.
She quickly removed her own clothes, wary of the state she was going to find Castle in.

When she stepped in the shower, she wasn't exactly surprised to see him shaking with the silent sobs he was trying to contain as tears rolled down his cheeks, though they were hardly distinguishable amongst the warm water that cascaded over his body, but it still sent a sharp stab of sympathetic pain through every fiber of her being.

When she touched his shoulder to signal her presence, he almost jumped out of his skin. And when his eyes found hers, he quickly puffed out his chest, straightened up, tried to pretend he was fine, even though he knew it was futile. He looked almost ashamed of himself.

Oh God, Castle.

"Don't do this, Rick." She told him for the second time that evening, stepping closer to him to wrap her arms around his waist and lightly kiss the underside of his jaw.

"I – I don't have the right."

"What are you talking about?"

"I don't have the right to cry for this. I mean you have suffered so much more than I have and here I am crying like a baby and –

"Stop." She interrupted him. "Just stop. Castle, I may have suffered a tragedy when my mom was murdered but I am also starting to see that I have had a much better childhood than you have. Until I was nineteen and until you wrote your first successful book, my teenage years were also probably better than yours. And you suffered, Rick. Not for the same reasons I did, but you suffered and you have a right to hurt. And I hope we will talk about it again at some point in the future, but for now, just let it out. Don't be ashamed. What your father said was completely out of line and I bet Martha is giving him another piece of her mind right now."

He didn't reply at first, just looked at her as if he were seeing her for the first time. So she cupped his face in both of her hands and rose on her toes to kiss him lightly.

"You're my partner. You don't have to hide from me, Castle, the same way I don't need to hide from you anymore. You taught me that, remember?"

He nodded.

"Good." She pecked his lips again before he brought them both down on the floor of the shower, tightly hugging one another.

She could still feel him shaking against her. She brought his head against her chest, caressed the back of his skull with one hand and stroked his broad back in soothing circles with the other.

"I love you, Rick. Just let it out."

So he did.

And when they went to bed that night, she asked him whether he knew what Friedrich Schiller had said about accidents or not. He shook his head, quiet and emotionally drained from everything that had happened earlier.

She smiled then, and wrapped herself around his body as her fingers brushed tenderly against his collarbone before she murmured her answer against his ear.

"There is no such thing as chance; and what seems to us merest accident springs from the deepest source of destiny."

He smiled a tiny smile, but he actually smiled, and she felt her heart soar with pride and joy at being able to do that for him.

"I thought you didn't believe in fate?"

She grinned and then proceeded to kiss the tip of his nose.

"Maybe you're rubbing off on me more than I let on. And just so you know: if anything, you are the best accident that's ever happened to me."