A/N: So it seems a few of you really didn't like the last chapter and a couple of you were very vocal about it. However, chances are if you leave me anon hate reviews, I'm not going to approve them.

I'm trying my hardest to focus on the good reviews as they seriously outweighed the bad but I always seem to focus on the negatives!

To those of you who left me nice reviews - THANK YOU. They always mean a lot but especially on the last chapter! You also took it to over 200 reviews which is just way more than I ever expected, so thank you soooo much!

Anyway, here's the next update..I just hope those hate reviewers are gone! Like I explained to some of you in messages, this chapter should hopefully resolve any issues, I think TORONTOSUN was the only person who figured it out! But trust me, it's probably not as bad as you think!

Still laughing quietly to himself, Castle climbed into the cab and gave the driver his address. Pulling out his phone, he rattled off a quick text to Kate, double checking she was okay - he wasn't too worried though, he highly doubted Charlie would have been playing games with him if there was something wrong with Kate.

Thinking of Charlie, he laughed again - had she really thought she could fool him? She should have realised that he knew Kate better than that, he had known about thirty seconds after he walked into the apartment that it was Charlie stood in front of him and not Kate. They might be identical but there were still little differences that you would only be able to pick up on if you knew one or both of them very well. For a start, when she was nervous or anxious, Kate's eyes went a shade darker than usual. Given the situation they had been in, with her running out on him, he would have expected that to happen and it didn't. That was his first indication that he wasn't really talking to Kate and as he spoke to her more, he realised it was pretty damn obvious it was Charlie. First, she had apologised about three times and after the conversation he'd had with Kate earlier, he knew that was unlikely.

He had to give Charlie some credit though, when he'd first seen her open the door he had been so worried about Kate that he had momentarily forgotten she had a twin sister. Well, that kind of news did take some getting used to, after all. But they weren't the same, not at all. Charlie had seemed a little unsure of what had actually happened and he knew Kate, knew that she stood by whatever she said and wouldn't seem unsure about why she had left. But if Charlie wanted to play that game, then so be it. He didn't know if Kate was it on it or not, but he'd try and figure that out the next time he saw her.

If he hadn't already been convinced, the moment he'd started bringing up how he felt about Kate had sealed the deal for him. The look on her face had been priceless, he could tell then that Charlie had never expected it to go that far and he would feel a little mean, except she had started it by not correcting him when he called her Kate. And as they say; all's fair in love and war.

Kate was fuming as she rode the elevator back up to her apartment, willing it to go faster. The cheek of Castle, laughing as he left, laughing at her no doubt, and the fact that he was playing her. Bastard.

For the second time that day, she slammed the door of her apartment closed, waiting for Charlie to appear.

"Hey, how'd it go with mom?" She asked, "wait, what's up? You look kinda..tense?"

"How could you?" She said quietly. "How could you do this to me? I've spilled my heart out to you more than once and this is what you go and do?"

Charlie looked thoroughly confused. "Erm, Kate..fancy explaining what the hell you're talking about?" She asked, having no idea what was going on right now.

"Don't even try and deny it, Charlotte! I heard you, both of you..talking," she sneered.

"Both of- oh, you mean Castle? Well why didn't you just say that?" Charlie asked, still ting to figure out what had got her sister so angry. "Listen, I have something to tell you-"

"Oh I'm sure you do," Kate interrupted sarcastically, "you've been back a week and half, Charlie, and you're already stealing my partner from me!"

"I'm- what?" Now she was really confused, what exactly did Kate hear? "I'm not stealing anybody.."

"Well then how do you explain what I heard?" Kate shouted. She couldn't believe Charlie had the balls to deny it to her face, literally ten minutes after the conversation had taken place!

"Right, you need to calm down," Charlie said and this didn't help Kate's anger. "I have no idea what you're talking about, but I'm sure you've got the wrong end of the stick." She had just realised that if Kate had got home just before Castle left, she could have taken the end of their conversation in completely the opposite way to how it was meant. Sort of. "So. What did you hear?"

"You and him," Kate huffed out, exasperation in her voice. "Him saying he shouldn't be saying these things but not being able to deny his feelings anymore-"

"Yeah," Charlie interrupted, he suspicions confirmed. "And you really think he was saying those things to me?"

"Well who else was he talking to?!"

"You, Kate. He was talking to you," Charlie said patiently.

"But I wasn't even- oh.." Realisation dawned as she took in what Charlie was saying. "He thought you were me?"

"Yes," Charlie said. "He came over worried about you because you rushed out with no explanation and just assumed I was you."

"That's all it was?"

"Of course it was, Kate. You don't really think I'd try and take him away from you, do you? Besides, that man is so crazy in love with you that Miranda Kerr could walk past him in her underwear and he wouldn't bat an eyelid. He loves you Kate, and I know you love him too."

"Oh god," Kate groaned, "I've been so stupid!"

"Well yeah, you have a little," Charlie laughed. "But you're in love and nothing's ever the same when you're in love. In fact, I think it's really just hit me how crazy about him you are, I've never seen you that jealous over a guy before!"

"God, I'm sorry, Charlie..I shouldn't have just assumed the worse but you know..when I heard what I did, it just kinda hit me and with what Castle said last week about me worrying he'd prefer you..I just jumped to conclusions."

"No problem, just..don't assume things next time, 'kay? I know how you feel about him and I would never, ever, do anything to sabotage that."

"I know you wouldng, I was just being an idiot! Anyway, I actually came back here to tell you I'm going to tell him. What I remember from the shooting, I mean. And I know he'll probably hate me, but I can't keep it a secret any longer, he deserves to know the truth."

"You're doing the right thing, Kate," Charlie said. "But do you wanna know the best part?" Kate looked at her enquiringly. "He didn't even figure out it was me!"

"Seriously? And you didn't tell him?"

"Seriously! And no I didn't, what would be the fun in that? I thought it would be really obvious but I think I've finally managed to fool him!" Charlie told her excitedly. "So..I was thinking..how about we play some of our old tricks again? You know, pretending to be each other..making him think he's forgotten to tell us stuff when he actually told the other one..that kind of stuff."

"You really think we could pull it off?" Kate wasn't convinced, if anyone knew her best it was Castle and she wasn't entirely sure he'd buy their act.

"Yeah I think so..and come on, from what I've learnt about Castle this is right up his street."

Yeah, and all his fantasies come true, Kate thought silently. "Okay, on one condition.."

"Anything," Charlie said, not even containing the excitement in her voice. She was a bit bored being back with nothing to do when Kate was at work, but now she had a plan. She would start looking for a job eventually, but right now she was just settling in back home.

"I still tell him what I heard and if he doesn't want anything to do with me then the whole thing is off, deal?"

"Deal."

"Well, no time like the present!" Kate said, pulling out her cell. She looked at the screen, noticing she had more texts from Castle. She replied to this one, though.

'You free for dinner or drinks or something later?' She typed, 'I should probably explain myself..'

A few minutes later, a reply came through. 'Alexis and I are having dinner and then a movie night if you wanna come? Charlie too?'

Kate wasn't sure. She couldn't really do that and tell him there, or go over tonight and pretend everything was okay just to tell him tomorrow.

"I'm busy tonight," Charlie said reading the message over Kate's shoulder and effectively making a decision for her.

She began her reply; 'no that's okay, you and Alexis have a good night. Tomorrow, if you're free?'

'Burgers at Remy's, 1 o'clock?' Came his reply.

'Sounds good to me, see you there.' She typed back, putting her phone down.

"So, sister of mine..where are you going tonight?"

"I um..just out. With a friend.."

"Oh yeah," Kate said with a grin. "Which friend?"

"Oh for goodness sake. Okay, so I met a guy last night and I'm seeing him again tonight, happy?"

"Ecstatic. But I was there last night, how didn't I meet him?"

"Oh you did, you were just a little drunk at that point."

"Oh, okay. So, tell me about him.."

Charlie rolled her eyes, seeing she wasn't going to be able to get out of this one. "His names Ethan, he's 35 and he's a property developer."

"Okay, and what does he look like?"

"Tall, dark and handsome and that's all you're getting," Charlie said, poking her tongue out at Kate.

"Spoilsport," Kate laughed. "Just remember to stay in public places and-"

"Kate, the whole cop thing was cute when you were a uniform but as a homicide detective, it's a little creepy. I'm a big girl, I can take care of myself!"

"I know, I know," Kate said as Charlie headed into the bedroom. "Just remember to use protection!" She called out jokingly and Charlie slammed the door behind her.

Right, so Castle and Charlie were busy..what was she going to do tonight?

"Charlie, is that my dress?" Kate asked, as Charlie emerged from the bedroom in the blue dress she had once worn to one of Castle's book signings.

"Oh..yeah, can I borrow it please?" Charlie asked with a grin.

"And if I said no?"

"I'd borrow it anyway, love you!"

Kate laughed, it was good having Charlie home. "Where are you going, anyway?"

"I'm not sure, Ethan text, said he'd booked a table at a restaurant, he's picking me up at 7..which is in 15 minutes!" She said, starting to panic slightly, she couldn't remember the last time she had been on a date.

"Oh relax," Kate said, "when he sees you in that dress he won't even want to leave the apartment."

"I'm offended, Katherine," Charlie said in mock horror, "I'll have you know that I do not put out on the first date!"

"Oh yeah, and what about Sam Carmichael?" She teased.

"Okay, that was one time and I was nineteen!" Charlie defended, "I'm a grown woman now, I need to have some respectability." She checked her reflection in the mirror one last time. "Just not gonna make him wait four years," she added as an afterthought.

"Oh shut up, Charlotte," Kate said, rolling her eyes as someone knocked at the door. "I'll get it!" She called.

"Don't you dare embarrass me Katherine Houghton Beckett!" Charlie hissed, nerves bubbling in her stomach.

"Would I do such a thing?" Kate teased as the opened the door.

"Hi! You must be Ethan!" She said, "I'm Kate, come in," she opened the door to let him in. "Charlie is almost ready.."

"Oh that's okay, I'm a little early," he said with a smile.

Wow, Charlie did good! Kate thought approvingly. She was right when she said he was tall, dark and handsome..she was guessing there was Italian or something in there somewhere.

"Can I get you a drink while you wait?" Kate asked.

"No need," Charlie called, "I'm ready now!" Last thing she needed was her sister saying something she shouldn't, especially when she was only going on her first date with the guy.

"Wow," Ethan said, "you look incredible!"

"Thank you," Charlie said, "you don't clean up so bad yourself!"

"So, you ready?" He asked.

"Yep, let's go," she replied, following him to the door, "bye Kate!" She called out.

"It was nice to meet you," Ethan said as they left, leaving Kate alone in her apartment.

A/N: *hides under pillows whilst waiting for more people to hate it*. Yeah, so I do really wanna keep going with this story because I'm having so much fun with it, but some of the anon hate is getting to me - not giving up yet though! Nice/constructive reviews are welcomed though, the majority of you have been SO LOVELY so far :)

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