A/N: THREE SHOT just for fun. What happens when Alt-Castle makes his way to our world? Sometime after 7x06.

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Rick woke with a hammering heart, a dry mouth, and the sun intermittently shining in his eyes. He blinked into the light, then straightened from his slumped over position and rubbed the stiffness out of his neck. Where was he? He glanced at his watch.

He was late for his lunch date with Captain Kate. Had he fallen asleep? How could he have fallen asleep? Well, of course he knew how, he'd been up all night playing poker and drinking whiskey, but still. He had a date with Kate, and he'd been looking forward to it. He looked around and found himself on a park bench he recognized, just off the sidewalk, not too far from the precinct. He must have stopped to sit for a second and just... fallen asleep.

Damn. Damn. Damn.

He rubbed a hand over his eyes and swallowed thickly. He felt oddly groggy. Man, he was getting old if one night of fun could still be kicking him around late the next afternoon. Then he glanced at his watch again. Two-thirty. That meant that he was hella late but it was early enough that she would still be at the precinct. It'd taken some doing to get her to agree to let him take her out, even just on her lunch break, he wasn't going to risk just not showing up.

This was the lady who sought him out and then turned him down. Kate had shown up at his door one day, greeting him like she knew him and not as if they were the strangers they were. But the pleased expression on her face had faded when he'd hit on her with a cheesy line and a leer, and it had disappeared completely when he was showing her around his loft. Most women liked the grandeur and the masculinity of his space, but she was left standing in the middle of it looking strangely confused. She said she must have mistaken him for someone else, that he wasn't who she thought he was.

He still couldn't quite wrap his mind around that, but she was consistently vague.

He'd chased her down the hallway as she retreated and asked her out in earnest, because she had managed to surprise him where so few women did. Because she was intriguing, and because she had a totally cool job. But she'd declined, backing into the elevator with something like loss written across her face. She was beautiful, more serious than most women he encountered, and she was super successful. And seriously! She had the coolest job. She carried a gun. She had a badge. Her name sounded like a super hero. She was in charge of all the other cops!

He had to know her.

So he tracked her down at her work and asked her out. She turned him down, again. When she turned him down again the next day, his ego was starting to feel the rejection. Rick Castle, once-famous author, didn't have to chase after women. Women loved him. Women threw themselves at him. But Captain Kate was resistant, and it took the next two weeks to wear her down. Finally, finally she'd said yes. Almost begrudgingly, but with an unconscious twirl of her hair that belied her irritation.

She was into him. This was going to be great.

And then he'd fallen asleep on his way to the precinct, the flowers he'd brought were nowhere to be found, and now he was jogging toward the precinct and wracking his brains for an excuse that would work. Oh no, there was no excuse that would work. None. He was going to have to throw himself on the mercy of the court and... huh. If he did that, did she have the power to actually throw him in jail?

Well, it wouldn't be the first time. And it might be kinda hot. She might think it was kinda hot if he was- But no! He was going to have to beg because Captain Kate didn't go for slick and sleaze and his usual playboy routine. He might have to be a little more than that.

Out of breath, Rick paused at the entrance to the 12th precinct to recuperate. Glancing idly around, he noticed that something about the street didn't look quite right. Breathing deeply and wiping the sweat from his forehead, he looked closer, but couldn't quite put his finger on it. Most likely they'd been doing construction, aren't they always, and now that the workers were gone the familiar area looked a little different.

Straightening his tailored, pinstriped jacket and finger combing his bangs so that they'd fall forward over his forehead, he entered the building. When he stepped off of the elevator at her floor he paused. He still didn't have a plan. Worst case scenario, she killed him and hid the body. Best case scenario she tried to ignore him completely. He could work with that. He already had.

He was still standing there, thinking, when he spotted the object of his affection walking right toward him. She looked a little different than usual, and he had time to wonder if she'd gotten her hair cut for their date before he buckled down for what was sure to be an uncomfortable encounter. Kate caught sight of him and smiled, smiled the frightening smile of supremely veiled anger, and approached quickly. She looked around with a sly glance, probably checking to see if there would be witnesses for the murder she was about to commit, and Rick tensed with a grimace.

"Look, I'm sorry-"

Then she kissed him. It was quick but warm with a small touch of her tongue at the corner of his lips before she stepped away with a grin. Rick gaped at her, speechless, absently dragging a thumb over his lower lip to swipe away the moisture there. She glanced around again and tugged needlessly at the hem of her ridiculously conservative button-down. When she looked back at him, it wasn't with anger. It was with curiosity.

"You change your cologne?"

"What? No?" He was so confused. This encounter didn't make any sense.

Kate stepped closer like she was going to kiss him again, and for possibly the first time in his life Rick moved away from a beautiful and willing woman. "Hey, you okay?" Kate asked him with concern. She looked him up and down. "You didn't pick up lunch?" She reached up and combed his bangs back from his forehead in disconcerting familiarity. Was she messing with him?

"No," he choked out. "I'm here to pick you up."

"What?" She sidled a little closer and slung the hand that wasn't caressing his temple around his waist. Suddenly, an angry voice cut across the room.

"Beckett, what the hell?"

Kate whirled away from him to look across the room, hair flying out in a fan, and did a double take. Rick could feel his eyes widen and his head physically jerk on his shoulders. There across the room, apparently in the middle of setting out a smorgasbord of take-out cartons, was him. Or, someone who looked a lot like him. But with less taste. He was wearing plaid.

Captain Kate looked back and forth between the two of them two, three times. Then she jumped away from him in alarm, drawing her weapon and sighting him before he even knew she'd left.

"Who are you?"

"I'm Rick Castle," he said dumbly. For some reason, he suspected it wouldn't be enough. It wasn't.

"No, I'm Richard Castle," the man who looked like him growled, stepping up next to Kate. They both stared at him. Suddenly, every cop in the place was watching, and at least two other detectives were soon flanking her, weapons ready.

"Please don't shoot me." Rick laughed nervously and shifted his weight.

"Beckett," an Hispanic looking cop hissed, "this has got to be a Jerry Tyson double. Another one."

The circle of faces glaring at him were grim with an incorrect assumption he couldn't fathom the depths of. "Guys," he tried, hands lifted in surrender, "I don't know what's going on here. I'm Richard Castle."

"No, you're not," Captain Kate said. "I don't know who you are, but you're not Castle. L.T., pat him down, please."

A uniformed officer approached cautiously but quickly and did as she asked. "He's clean, Detective."

The weapons aimed at him lowered and some of the crowd began to dissipate, though the officers milling back to work were still obviously listening to the exchange.

Just then a sharply dressed black woman stepped off the elevator behind him, glancing up from a file as she passed to give him a look of inborn dislike over black-rimmed glasses. Her eyes flicked back to her reading for a split second before she seemed to take an instinctive stock of the tension in the room. She stopped, looked from him to Kate to that other Rick Castle and back to him again.

"Oh dear Lord, there's two of them." She pinched the bridge of her nose and closed her eyes, audibly muttering under her breath, before she pointed a finger at Kate. "It was a good idea to keep me in the dark, Detective."

There it was again. Detective?

"Sir?" Kate asked.

"Twins," the woman grumbled as if to herself. "Of course Castle has a twin. Of all people."

"I don't have a twin."

"We're not related."

He and his doppelganger spoke at the same time. The other Rick glared at him, and now he was getting annoyed. Who was this Rick to be annoyed at him? Who was this guy to put his arm around Captain Kate as if he knew her like that? Now the new woman looked almost as intrigued as she did annoyed.

"Sir," Kate said again, "this man claims to be Richard Castle."

Frustrated anger was starting to build in his belly. "I am Richard Castle. You know me."

"Dude, I'm Richard Castle."

"Castle," Kate laid a hand on the other man's arm which seemed to soothe him. She turned back to him. "I don't know you."

"Seriously, Captain Kate, I don't know what's going on here, but you know me. I was coming to pick you up for a lunch date."

The other Rick... Castle seemed to sit up straight at that. He leaned forward and stared at him, but without the earlier dislike. Instead, he looked sloppily curious. "Oh my-" he muttered. But the women didn't seem to hear him.

"My only plans for lunch today were take-out over paperwork." She gestured to the cartons on the desk behind her, then turned toward her superior. "Captain," Kate said, "I'm at a loss."

"Sir," the captain who wasn't Kate turned to him. "Do you have any identification?"

Rick nodded eagerly and jammed his hands into his pockets. They were empty. When he looked sheepishly up again, the captain was unimpressed. "Mister... Sir," she caught herself, "I'm going to have to ask you to come with me."

"Captain Gates," Castle held up a hand to stop them, and the captain gave him a look of oft-tested patience.

"Yes, Mr. Castle?"

"You called her Captain Kate." It was a statement, directed from that other Castle to him. When he nodded, Castle held his fingertips to his mouth in a pathetic imitation of excitement. Seriously, this guy did a really weak impression of him.

"And," Castle continued, "let me guess. When you've met Kate in the past, has she been dressed a little differently? A skirt, more expensive suits, black from head to toe?"

"Castle," Kate hissed. "What are you doing? I've never met him."

"Yes!" Rick interjected before anyone could throw him in lockup. "Yes, she was dressed much nicer than she is now. I'd never have pegged her for that ugly blouse."

"Hey!" Kate glanced down at her own outfit and crossed her arms over her chest, defensive.

"No, Kate, I think I know what's going on here." The other Castle stood and slowly approached him. "I think," he squeaked around the fingertips again pressed to his mouth, "that he's from a different universe!" Then Castle approached and poked him carefully with an outstretched forefinger, as if to make sure he was really there.

Captain... Gates? Captain Gates closed her eyes and slowly pressed the manicured fingers of each hand to her temples. "Lord help us," she muttered. "I need some aspirin."

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A/N: Thanks for reading! I'd love to know what you think. Got the idea for this while watching the episode of Fringe where the two Astrids meet for the first time, and my title is from a different episode of Fringe as well.