Author's note : So watching Demons, I found some stuff odd between Castle and Beckett :

He grabbed her.. butt, I guess. Something that wasn't her legs anyway

And when she gasped "Cas" (the "tle" wasn't there or very low), she didn't seem that annoyed.

The comment about about the massage. She didn't seem phased by that either. The awkwardness of the end of Heroes and Villains was gone.

So, here's my theory. Maybe as crazy as Castle's CIA one. And I'm posting it before Cops and robbers airs because it might be AU by then. Tell me what you think. It takes place between Eyes if the beholder and Demons.

"Plus, I only broke one panel. Why are they making me pay for the whole thing?" Castle continued to rant, in between bites of his burger.

"Can't your insurance pay for it?" She asked, sipping her milkshake.

"Why can't their insurance pay?" His outcry provoked a shift in Beckett's posture. He saw her tense up and immediately regretted bringing the museum assurance up.

"You should asked Serena..." She said, pushing her drink away and sitting back.

He put his burger down, swallowing the large bite in his mouth slowly to give him time.

The atmosphere had changed and Beckett berated herself for causing it.

"I'm sure she's not interested anymore."

"Why?"

"Oh... Just something she said."

"What did she say?"

She was really curious about why they didn't go out. He hesitated, wondering how much to tell her. She had already asked him that same question earlier. He had deflected with a joke. This time, she was pushing for an honest, serious answer, he reckoned.

"She told me she doesn't steal things that belong to someone else," he deadpanned, staring at her.

She hold his gaze for longer than he expected. Eventually, she looked down and started to play with her glass.

"Sorry," she whispered.

He touched her hand to make her look up.

"Not your fault." His lips quirked up sightly. "Well, maybe just a little, but..."

Beckett was fighting to control her breathing. She knew she was the one who started this all thing with her jealousy. And she didn't know how to stop it.

"She isn't my type anyway."

Banter, she could do banter. She plastered her teasing smile on her face.

"Like you have just one type, Castle?"

But he remained serious.

"I do. Tall, brunette, strong, hot..." He gave a short saucy smile at that one before going on. "A mystery I am never gonna solve. In one word : extraordinary." She shivered because of the words or because of the low, deep tone. Most likely because of both. She didn't dare to look at him, focusing on his forgotten burger instead. "You know." He added, like an after thought. But the tone was different. It wasn't a question but a statement. Her eyes met his. They were wide with realization. "You know," he repeated.

There was no denying it. It would only make it worse. This morning, in her therapist's office, she hadn't been able to say it. Say that he wasn't supposed to be "smitten" with this other woman when he was supposed to love her. How could she asked of him to act accordingly when she didn't even acknowledge it ?

"Yes. I remember."

He nodded gravely, silent for longer that she liked. He was giving this revelation a lot of thoughts. He tried to see this as a writer and understand the consequences. Finally, he sighed, closing his eyes. "It doesn't change anything." He opened his eyes and started on his burger again. She didn't know what to say so she went back to her own meal. And they finished their meal in companionable silence.

After they finished he went for his wallet but she stopped him.

"Hey, my treat ! You can't afford it, remember," she joked.

"Remember when we were pretending everything was fine. Yeah, I remember it well," he thought but pocketed his money instead. "Thanks, I'll pay you back when Alexis will be able to give me allowance."

She gave him a bright smile, happy that the banter was back. But as they walked out, he was somber again. She headed to her car but stopped when she saw he hadn't followed, hailing a cab instead.

"You don't want a ride?"

"No it's okay, It's out of your way. Goodnight." He said as he opened the door.

"Castle?"

"Yeah?"

She took her time, wanting to say something but not sure how.

"See you tomorrow?"

"Of course!" He gave her a quizzical look, like he knew that it wasn't what she wanted to say.

"Goodnight."

She stood on the side walk, watching the taxi disappear into the traffic.

The buzz of his phone stirred Castle from sleep. He looked at the clock before grasping the offending object. It was a text, from Beckett, at 5 AM.

"You're wrong," it read. He shook his head violently, trying to wake up, because half asleep, this text didn't make any sense. He reread it after a minute. Still not making sense.

He typed a quick response. "About what?"

The answer was quick. "When you say it doesn't change anything." His heart sank. Why was she doing this to him? For once, he would have been quite happy about ignoring the whole thing. The next text puzzled him even more : "Come in early! See you in half an hour."

He gave up trying to understand and got up. If he wanted to be there on time, he needed to get in the shower. But did he really want to be on time ? And for what? Having his heart ripped apart?

Forty minutes later, he arrived at the precinct. It was still dark but Beckett was waiting outside for him with two cups of coffee. When she saw him she smiled brightly and handed him a cup.

"Good morning. I thought that with the short timing, you wouldn't have time to stop for coffee."

He eyed her suspiciously. She was way too bubbly for 5:45 AM. She was too bubbly for Beckett.

"Thanks," he said as they walked in. If he was surprised by her request and demeanor, it was nothing compared to his shock when they got in the elevator. As soon as the door closed, she stepped in front of him, really, really close.

"I hated the way Serena looked at you. I hated more the way you looked at her. I was jealous and she's right, I do think you're mine." Then she leaned towards him. He thought he might have an heart attack. Careful not to spill her coffee, her arms went around his neck. Her lips hovered above his for a second. She looked in his eyes, at his lips, then in his eyes again before kissing him. He closed his eyes, enjoying the feel of her mouth on his. When he opened them again, she was gone. The elevator's doors were open and he was alone. Her head reappeared suddenly, startling him.

"Castle! You're coming?"

He hurried behind her. She was going straight for the empty break room.

"What was that?", he whispered once she had closed the door.

"That was me changing my mind about... this... us." She said gesturing between them with one hand.

Castle looked around wildly. "Am I being punk'd?"

She swatted his arm for this.

"Ouch."

"You're not being punk'd!" He still didn't believe her, she could see it on his face. He was not a morning person, maybe she should have waited. But she barely slept all night. Her ride home had been enough to take a decision, this decision. Even if she thought she needed to solve her mother's case first, she wasn't ready to watch him with other women. So she just had to make it work. To convince him it wasn't some cruel joke, she put away both their cups and kissed him again. This time she lingered a little longer. The bullpen was deserted at this hour, no risk to get caught. He encircled her in his arms. She allowed him to deepen the kiss, his tongue passing past her lips to meet hers. When his hands traveled down to cup her ass, though, she pulled away. Resting her forehead against his, she took the time to catch her breath. Eventually she stepped away from his embrace.

"We need some ground rules," she started. "First. No kissing at work. That includes the precinct, crime scenes, and everywhere we go for a case, alone or not..." He opened his mouth to object but she anticipated and cut him off. "First and only time! Well technically, it's two times, but you were being dense. Anyway, last time. Second. Let's keep it quiet for now. This is difficult enough without everyone teasing me about it. Plus I don't know how Gates would react.. Third. Dates are okay. Only if it's not too obvious. No overpriced restaurants for example." Beckett was pacing in front of him, only looking at him from time to time to make sure he was listening. Castle just stood there, staring. "That's all. For now." She turned to him expectantly. "So what do you think. Do you agree?"

He smiled at her then. A soft, gentle, happy smile. Walking up to her, he moved quickly to kiss her.

"I agree," he said once he had pulled away.

"You broke rule number one," she whispered.

"I'm sorry. Won't happen again. I promised we will take this slow, but you need to relax. This..." he made the same gesture with his hand between them. "is going to be just fine." She nodded wordlessly, not breaking eye contact. The moment was interrupted when one of the uniforms came in for coffee. Beckett took hers and walked out. Castle followed grinning like the cat who ate the canary.

"Number four. Wipe that silly smile off your face."

"Yes, dear..." He said, adding immediately : "Let me guess number five."