Okay so this story will be following the TV show. Thalia will be 19 (appearance wise). So here we go hope you enjoy. You will notice that I have not included all the parts for the episode, I will only include the parts which I change my self so you better watch the episode before reading this.

I have also decided that I will only be uploading small amounts of the episode since I have found it very hard to try and write the whole episode so instead I'll be updating the episode in thirds/quarters. and sorry I've taken so long, I was in Spain recently. By the way when some writing is in italics it's a thought or dream, but there aren't any dreams yet, well hope you enjoy.

I do not own any of the characters

Know Thy Enemy pt. 1

Salvatore House

Stefan and Damon are walking down the stairs talking.

"Isobel just showed up at their front doorstep" Stefan concluded

"What's she doing here?" Damon asked

"I don't know. That's what I'm gonna go find out" Stefan decided

As they reached the ground floor, Katherine walked in. She had her normal curly hair and was wearing a grey top with some black skinny jeans and some high heels.

"I don't think that you should tell her that I'm here" she advised

"What? Why?" Stefan asked

"It's better if she and John not know that I stayed in town after I got out of the tomb"

"You're the one in cahoots with them. You made a deal with John that almost got me killed" Damon Accused glaring at her.

"I did what I had to get out of the tomb. Now I'm reconsidering my alliance." Katherine countered

She starts to turn around but before she can say anything else Stefan interrupts her, "What do you know?"

"I know that I want Klaus dead, which puts me squarely on team you. Besides, if you two ever need me to swap places with Elena again, the less people know that I'm here, the better. Think about it, Stefan. Come on. Be smart."

"Tell you what. Why don't you, uh... Call Alaric and let him know that his wife just showed up on his girlfriend's doorstep, while I call an old friend" Stefan turns to leave but Damon stopped him.

"What old friend?"

"Someone I met during one of my darkest times"

He looked at them and left, leaving Katherine and Damon to wonder who this mystery person was.

Caroline's house

Caroline was talking on the phone to Stefan while walking to her car, they seemed to be talking about Mat.

"I can't find him anywhere. He's not at home. He's not answering his phone." Caroline was worried, she didn't want Mat to leave her, or to ignore her, maybe ignoring her was even worse.

"How could you let him go?"

"My mom walked in. He took off. I didn't know what to do."

"Did your mom hear anything?"

"No. She just thinks we're fighting but he knows about me, and he's freaking out about Vicki."

"All right. Listen. You have to find him. You have to calm him down. Compel him if you have to. Is he still on the vervain?"

"I slip it into his soda when he's at work, but I didn't get to last night, so it's out of his system. He has a catering shift at the Lockwood's' today. I'm gonna try there. And who is this mystery person Damon told me to ask you about."

"She is an old friend, and I think she can help us"

"As long as she can, and is willing to helps us I'm fine, but what is she like?"

Stefan's chuckle could be heard through the phone. "You'll soon find out"

Defeated Caroline hung up the phone to try and call Mat again but he didn't answer, so she continued to drive to the Lockwood's estate.

Gilbert's house

Elena and Stefan were in her bedroom.

"Ah, this is bad. Between Isobel and Jenna and now Matt, this is disaster bad." Elena couldn't help it she was on the edge of screaming, if anything else were to happen she might just end up screaming until her throat was raw.

"Yeah." Stefan didn't know what else to say.

John then walks in an starts to ask Elena and Stefan to come with them, it takes a while for them to agree to go with him with some persuasion he got them to go downstairs with him and that is when Isobel walks out of the kitchen.

"I asked John for a do-over." Isobel simply stated

Elena was completely shocked to see her in her house, "You invited her in?"

"She has information about Klaus. Please, just listen to her, ok?" John tried to reason

Elena looks to Stefan to see what he thinks is the best thing to do.

Stefan decided the best thing to do was to hear her out and decide what to do from then, he was still wondering if she would be able to come, she said she would try, but she couldn't make any promises. "All right. What do you know?"

Isobel walks back into the kitchen where the others follow and starts to tell them what she knows.

"Since I was last here, I've been doing everything possible to find Klaus. We knew our best chance was to find him before he could find you."

"Best chance at what?" Stefan asked

"Keeping Elena alive." John answered

"You don't get to talk, ok, not after everything you've done." Elena stated

Stefan knew this was an argument not needed right now, so he decided to change the subject. "Were you able to find Klaus?"

"No. Nobody knows where he is but there are these rumours that are flying around. That a doppelgänger exists." Isobel confessed

"Which means any vampire that wants to get in favour with Klaus will be lining up to capture you." John concluded.

"I'm not buying any of this." Elena stated she then turned to Isobel. "The last time that you were here, you made it clear that you didn't give a damn about me. Now all of a sudden I'm supposed to believe that you want to help?"

John decided to stop another argument from starting and he decided to say something "Isobel's been helping all along. Klaus has been obsessed with finding Katherine for centuries. All it would take was any one of those 1864 tomb vampires to spread the word around that Katherine was still alive and it would bring him straight here to Mystic Falls, where you were bound to be discovered, so we killed them."

"And almost killed Stefan and Damon in the process."

Isobel stood and then walked towards Elena, she then said "I have a safe house that I can take you to. The deed is in your name. No vampires can get in without your permission, not even me. Let me help you."

"You wanna help? Then get the hell out of my house." Elena shouted

Isobel decided it was best to and did so, John however decided to try and make things a little worse for Stefan. "So I heard you were inviting an old friend into this whole Klaus trouble."

"Wait, what?" Elena asked, right now her head was about to explode, and now she finds out that her boyfriend has decided to bring someone else into this fight.

"I was going to explain it to you later, but I guess I have to tell you now." Stefan started. "She's an old friend I met, back in my dark times. She's not a vampire, nor is she human really, well half human to be exact."

"Do you mean she's a ware-wolf?" Elena asked confused

"No. Well she's a, erm ... I'm not sure how to explain it without her here as proof..." Stefan couldn't put it into words, even though Elena knew there were vampires and ware-wolfs doesn't mean she won't think he's crazy for saying his friend was half god.

Thankfully his phone starts ringing, speak of the devil, Stefan thought. "Just one moment" he excused himself and answered the call.

"Hello"

A girls voice could be heard through the phone, "Stefan hi, long time no speak"

"Yes it has been a while since we've contacted each other"

"Yeah and out of the blue you just ask me for help?"

"You know I wouldn't call unless it was necessary"

"Yeah, yeah, yeah. So I'm at some restaurant called Mystic Grill"

"Ok I'll pick you up there, don't move from the spot in which you are standing now, ok, stay!"

"Woof" was herd as Stefan hung up the phone.

"Come on I'll take you to meet her" Elena and John made to leave but Stefan stopped. "Not you John, still mad at you" after leaving John back at the house Stefan and Elena soon arrived at the Mystic Grill. When they entered Elena came to see a face she has never seen before, while Stefan came to see the face of old friend, who had sort of helped him during one of his dark times. Stefan led Elena to the girl sitting by herself, the girl looked up at them when they approached her table, and she looked to be around 19 but when you looked into her eyes she looked much older. Stefan was smiling as he sat down at the table, while Elena, who knew nothing about the girl, was a bit careful.

"So what's this big vampire problem you have?"

"It's good to see you too Thalia, how have you been? It's always straight to the point with you" Thalia only stared blankly at him. Stefan then sighed and started to explain the Klaus problem.

Back at the Salvatore house

Elena, Stefan and Thalia had gotten back to Stefan's house, where she is also staying while she is in Mystic Falls. All three plus Damon were in the library. Thalia had already been informed of everything that has happened in this town by both Stefan and Elena. Every so often Thalia would fidget with her hands and Damon would always be able to catch it in the corner of his eye, you could tell by his face this girl was annoying him already.

Elena had found out that Thalia had met Stefan a long time ago, Stefan had actually tried to drink her blood once but was not able to as her blood was different, for she was a demigod, and demigod's blood is both human and immortal, and the immortal blood makes it unable for vampires to drink, it's sort of like poison, and makes the drinker's mouth burn. But before Stefan was even able to drink from her, she flipped him over her shoulder so that his back was against the ground and she held a broken branch in her hand, of course they talked it out instead of trying to kill each other and Thalia tried to help him while Lexi wasn't there to help him recover.

"Do you really think that Isobel's telling the truth that word's gotten out about the doppelgänger?" Elena asked.

"Look, I don't trust a word that she says, but I think we'd be stupid to ignore the warning." Stefan decided.

"You know, you should just stay here. It's better for us to keep an eye on you." Damon said

"What, in the house that any vampire can enter? No. Her house is safer."

"How come any vampire can come in?" Thalia asked

"Because only vampires live here therefore any vampire can enter" Stefan answered

"Back to the problem at hand, then we'll be staying there."

"So is that the plan? Neither of you will let me out of your sight again?

"Let me know when you come up with a better one." Damon remarked

"Fine. Then one of you 2 bodyguards is gonna have to come with me to the Lockwood luncheon." Elena grumpily replied

" That'd be me." Stefan decided, Elena merely nodded with this statement, While Thalia watched them she could tell they loved each other very much but she could also tell that Elena was not at all happy walking around with the two brothers always at her sides.

"Not me. I have witch stuff to attend to with Bonnie. Thalia why don't you join me, it would give us a wonderful way to get to know each other." Damon did not know yet about the fact that Thalia was a demigod and he wanted to know what made this girl so special that Stefan would want to bring her into a very dangerous fight that only the toughest should be present.

Thalia considered his offer, she shrugged and answered with "why not".

" Does that mean that you're taking her to the…" Elena started only to be stopped by Damon. He shushed her, because he could hear Katherine approaching and he did not want her to know what he would be up to.

Katherine then walked in as proudly as ever without even noticing Thalia's presence, and the younger was too busy trying to read a book she had found to be paying attention to the fact that Elena's doppelganger had just walked in.

"Don't get quiet on my account. If you have a plan to combat the impending vampire doom, please do tell." She finally noticed Thalia quietly standing beside Damon and Elena trying to a read a book. "And who is this?" she asked, Thalia looked up from her book with a blank look on her face, when she noticed Katherine standing there she turned to look at Elena then back at Katherine. "You must be Katherine, I'm Thalia" Thalia nodded towards her, then turned her attention back to the book.

Katherine shook her head and continued to talk to the others "Back to the first statement do you have a plan to tell or not?"

When no one answered Katherine began to get frustrated.

" Seriously, what is the plan to get us out of this mess, hmm? I delivered you a moonstone, a werewolf, and the dagger to lure and kill Klaus, and right now all you have is a moonstone. Or so you tell me." Katherine was trying desperately to get on their good side, she needed that moonstone and she would stop at no costs to get it back.

" No, we have it." Damon shot back

" Where is it?" Katherine asked, god they are unbelievable.

"It's in a very safe place." Damon smiled as he said this, he was enjoying tormenting her.

" I've been honest with you. Time to return the favour."

Thalia had put down her book a while ago and watching the little argument, smirking at the fact that Katherine was practically begging to be in with the rest of the group, she herself did not know where the moonstone, she didn't even know what it looked like but she still found this conversation amusing "If I may intrude, from what I've heard you haven't really been the most trustworthy person, and one act of charity does not mean all is forgiven, for all they know you could be tricking them to get the moonstone to save your own sorry butt." Thalia couldn't help but adding her own input, plus the look on Katherine's face made it totally worth it.

"Yes, listen to Thalia. And don't mistake the fact that we haven't set you on fire in your sleep for trust."

Elena just ends up smiling smugly while Katherine gets even more frustrated, much to Thalia's amusement; Thalia also fought the need to pull her tongue out like a young child but fortunately was able to fight back the urge.

"Fine. Be that way."

Katherine left with a frown on her face, I guess I'll just have to find that stone my self.

When she left Thalia couldn't help the small chuckle that escaped from her mouth. Damon then turned to her and said "we should go now Bonnie is waiting for us, I told her I'd introduce the two of you."

"Aye, aye captain." Thalia said with a small smirk on her lips, which Damon couldn't but give a slight twitch at the corner of his lips at, I have I feeling I'll warm up to her quite easily, he thought to himself.

I have also decided that I will only be uploading small amounts of the episode since I have found it very hard to try and write the whole episode so instead I'll be updating the episode in thirds/quarters.