Author's Note: This has been in my brain for weeks, but I've been having a hard time getting it on paper. I was determined to get it done. It was inspired by a tweet in the middle of September from Penny Johnson Jerald (aka Captain Gates). Read the story first, then I'll tell you at the end what the tweet said!

Disclaimer: I don't own the show Castle, or any of its characters, I just love them!

By The Book

"Detective Beckett! Mr. Castle! Both of you! My office, NOW!" bellowed Captain Gates.

Castle and Kate both jumped at the sound of their names and the tone in the Captain's voice. Kate sat at her desk, completing paperwork from the latest case and Castle sat on his chair, quietly scrolling through emails on his phone, trying to be patient, as he waited for Kate to finish. She had promised to come home with him for a quiet dinner at the loft once the case and its related paperwork was finished. They had both been looking forward to spending the evening in each other's company, and Castle was sure he wouldn't have to try very hard to convince Kate to stay at his place for the night.

Now, though, they had been summoned to the Captain's office and they were both fairly certain they knew what it was about.

When Castle and Kate's relationship had changed from "partners" to "romantically involved", they had decided to keep it their own little secret for as long as they could. Not that they liked lying to their friends and co-workers, but they simply felt their new status was something too precious to share with anyone else right away. In the beginning, they both may have had fleeting doubts about whether or not things would work between them, but those feelings quickly dissipated, as their shift from partners to lovers was almost seamless. Suddenly, there was a closeness between them that had not been there before. They were in sync in a way they had never been in the past. Then, the secrecy just added to the excitement of this new relationship. The stolen glances and innuendos held an even deeper meaning for both of them, as each seemed to know the other's thoughts even more than they had before.

Slowly, however, the secret had been found out. First, by Ryan, through no attempt of his own, during the Hampton's case. Then Ryan had told Esposito and Kate had told Lanie during the 3XK case when Castle had been charged with murder. Once things were out in the open with their friends, Castle and Kate had been more relaxed at work, and had not been as careful to keep their feelings hidden. From stolen moments together in a quiet corner of the precinct, to lingering touches of fingers as coffee cups were passed from one to the other, it was becoming more obvious to anyone who cared to take note. Some of the other detectives on their floor had found out, then a few of the uniforms, until it didn't seem like much of a secret anymore. It seemed that Captain Gates was the only one still in the dark, and the only one they were really concerned about keeping in the dark.

But now, here she was, summoning the two of them to her office, and their only assumption was that she had finally found, or figured, it out.

With fear and trepidation, they both rose from their seats. Their eyes locked for a moment, as each read the other's thoughts. Would this be the last day they worked together as partners at the 12th?

Slowly, side by side, they made their way to Gates' office. At the doorway, Castle stepped aside, letting Kate enter ahead of him, for once not minding if she wanted to be first through the door. Once inside, Castle closed the door behind him, to keep, hopefully, some of the expected noise from escaping the Captain's office. Not that a closed door would keep the rest of the floor from knowing what was happening, with the office exposed to the entire bullpen by a full wall of windows.

Captain Gates motioned for Kate and Castle to take a seat on the chairs in front of her desk, which they did, and for a few moments the room was so quiet, you could have heard a pin drop. Gates sat behind her desk and solemnly took in the two people in front of her. The nervous energy they were emitting was so thick it could be felt in the air. Gates stood and slowly walked around to the front of her desk, where she leaned back against the edge and crossed her arms over her chest.

"Mr. Castle. Detective Beckett," she began. "It has come to my attention that you have been keeping something from me. I think it's time we cleared the air."

Castle and Kate looked up at Gates, eyes wide, and both audibly gulping, trying to decide how to even begin to defend themselves.

"Keeping something from you, Sir?" Kate asked.

"Yes," Gates replied. "Something that could impact your work here. And don't play dumb with me."

"Ah, ... no, ... Sir," Kate responded.

Seeing that the conversation was going nowhere, and Beckett and Castle were apparently not going to give anything away voluntarily, Gates decided to plunge right into the uncomfortable subject.

"It has come to my attention that the two of you," stated Gates, directing her gaze from one to the other of them, "are in a romantic relationship. Is this true?"

At that, Castle's mouth opened with a very audible intake of air. His eyes shifted sideways to Kate, but as her eyes never left the Captain, Castle quickly looked back in the same direction.

The office was silent for a few moments, but it soon became obvious that the Captain was going to wait them out. Kate mustered all the inner resolve she could find and answered, "Ah, yes, Sir . . . yes, it's true."

"And are you aware, Detective Beckett," continued the Captain, "of the regulation of the NYPD forbidding co-workers from engaging in such relationships?"

"Yes, Sir, I am," Kate replied quietly.

"And yet, you have not only allowed this to happen in the first place, but you have continued with the relationship, while remaining on as members of my team?" Gates questioned.

"Yes, Sir, I guess that would be correct," Kate answered.

Suddenly Castle realized that Kate was floundering. Detective Kate Beckett who was always so sure of herself, was now unsure of what to do. And Castle realized that if he didn't do something quickly, things would get out of hand. There was no way he could sit back and let Kate bear the brunt of this, and if he did, he was about to watch himself get kicked to the curb, which he was not about to do! So, with an idea which had been in his mind for weeks, he jumped in.

"Um, Captain, if I could speak for a moment?" Castle questioned.

Gates looked at Castle and replied, "Well, Mr. Castle, do you have something you could add to this discussion? "

"Actually, yes, I think I do," he answered. With a nod from Gates, he proceeded. "Captain Gates, would I be correct in saying that you are typically a 'by the book' sort of person?" he asked.

"Well, yes, you would, Mr. Castle. I pride myself on it."

"I thought so," he continued. "And this regulation you spoke of earlier, about co-workers. How exactly is it worded?" he asked.

"It is worded just as I explained earlier, Mr. Castle," she responded. "It states that co-workers cannot be romantically involved. If they are, it jeopardizes their safety - "

"I'm aware of the reasons for the rule," he interrupted. "If I may ask another question, just how is the word 'co-workers' defined?"

"Well, just as you would expect," she replied. "Co-workers are any employees of the NYPD who work in the same division of the force. They can be partners, or simply members of the same division. So, you see Mr. Castle-"

Castle cut her off again. "And would I be correct in stating that an employee of the NYPD is anyone who is receiving a pay cheque from the NYPD?"

"Why, yes, Mr. Castle, you would," she answered.

"And would I also be correct in stating that these rules do not apply to anyone who is not an employee of the NYPD?"

"Once again, Mr. Castle, you are correct." Suddenly, Gates, seeing where Castle was going with this, tried to protest, "But that doesn't mean-"

Once again Castle cut her off. "So you see, Captain Gates, since I do not receive a pay cheque from the NYPD, I am not considered an employee of the department, and therefore, technically, I'm not Detective Beckett's co-worker. I'm simply a civilian voluntarily doing research for a series of novels I happen to be writing. The rules regarding co-workers do not actually apply to me, and since you have already admitted that you like to do things 'by the book', I think you'll have to agree that Beckett and I don't fall under this particular set of conditions. So, there would really be no justification for you to terminate my work with the department, would there?" Castle asked. He raised one eyebrow as he looked directly at the Captain, and she met his gaze with an intense one of her own.

A long sigh escaped her lips and she slowly shook her head side to side. She pressed her lips firmly together, the hint of a smirk starting at the corners of her mouth, but she contained it, as she realized that she'd been had.

"Mr. Castle," she began, "you state your case well. Perhaps you should have been a lawyer. Fine ... I suppose I don't have a legal leg to stand on. Alright, I guess I really can't do anything about this relationship you two have going. But, Mr. Castle, if I find that it in anyway jeopardizes any of Detective Beckett's cases-"

Once more Castle cut her off, "It won't," he almost shouted. For the first time since he had jumped into this, he looked over at Kate. What he saw almost took his breath away. She was looking at him, wide-eyed, with the biggest grin on her face he had seen in awhile. He grinned back at her, realizing what this meant. He wasn't kicked out, he was staying. They were still partners, would continue to be partners, without the burden of hiding their feelings any longer. Castle reached out and gave Kate's hand a quick squeeze, then jumped up and did something totally unexpected. Turning to the Captain where she still stood in front of her desk, he grasped her by the shoulders, and before he could even think about what he was doing, he pressed his lips to hers in a huge "smack" of a kiss! Still hardly aware of what he had done, he turned to Kate, threw his arms around her waist, picked her up and twirled her around in a complete rotation, before setting her feet back on the ground, and planting a quick and noisy kiss to her lips as well.

Behind him, Castle heard the steady voice of the Captain, "Mr. Castle?"

"Yes," he said hesitantly, turning around to face her.

"One more thing," Gates continued. "There will be no PDAs in the precinct from here on out, is that understood?"

"Y..yes," he answered. "Understood ... completely."

"You are both dismissed. Get back to work," Gates instructed.

Castle and Kate very quickly exited the Captain's office. Had they turned around, they would have seen Captain Gates still leaning on her desk, arms crossed, one hand under her chin, and very slowly bringing her index finger up to run it across her lips, a small smirk on her face. She only let it linger there a moment, before she stood up, straightened her suit and returned to her chair behind her desk.

Author's Note: Okay, the tweet from Penny Johnson Jerald on September 13 said: "Had to get the name of Nathan's lip balm. No man should have lips that soft. :) Jealous!" I started to think, "why would Penny/Gates know how soft Nathan's/Castle's lips are? So, you see, this just jumped into my head and I couldn't get rid of it until I wrote it down! I actually would like to write another one where a similar thing happens under the mistletoe, but I don't think I have time to get it done before tomorrow's episode, and I have this funny feeling ... hmmmm...

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