Disclaimer: I don't own Supernatural.

The next two weeks flew by and Claire's routine at the bunker went back to what it had been before she found out about her mother. She trained with Castiel, researched in the library and had movie nights with the guys. Slowly she started to feel that she was one of them, maybe even part of the family. Sam always treated her as she thought a big brother would, Dean looked out for her like her mother had when she was little and Castiel was just there. A solid presence who radiated safety, like a father.

She'd been thinking like this for a while and had decided today was the day to make it official. With that in mind she made her way to the library where everyone was working.

"Umm, guy's I've made my decision." She said to the room causing three heads to come up.

"Decision about what?" Dean asked confused.

Claire took a deep breath before she said "I'd like to stay. Permanently if you'll have me."

At that Castiel smiled at her while Dean yelled "hell yeah." And got up to give her a big hug.

Sam stood as well and when Dean released her he pulled her into a hug of his own saying "welcome to the family."

With that decided they all sat back down to see what they could find to keep their family together.

Claire was on the verge of giving up for the day when she saw it. It was in a book of prophecies that the men of letters had but hadn't seemed that interest in. It was an old book the leather bindings were cracked and she had only started reading it because they had pretty much read everything else. She never thought it would be useful but there in front of her were the words they had been looking for.

"I think I found It." she said to the room with a voice filled with awe causing everyone to turn to her.

Sam was the first to speak unable to contain his excitement. "A way to remove the Mark of Cain?" he asked.

"Not remove it no. but a way to contain it." Claire replied before handing the book to him at his confused look.

Sam took the book from Claire and skimmed the page she had been reading until he found the relevant passage which he read out loud.

"The Mark of Cain can be held at bay by finding the human who is markeds soulmate. Their purity will cancel out the evil hold the mark has on the barer thus rendering it inert."

"Wait what? We have to find my soulmate?" Dean asked incredulously. They couldn't be serious.

"Yeah looks like." Sam replied wearily. He knew Dean was going to fight this.

"How the hell do we do that?" Dean asked again. How was he supposed to find his soulmate? Go out trawling all the bars until he stumbled onto her?

"We ask a cupid." Castiel replied speaking for the first time since Claire had found the passage. He wasn't sure how he felt about this turn of events but he knew he felt something at the idea of Dean having a soulmate. No that was a lie, he knew what that something was. It hurt. He knew nothing would come of his love for Dean but the thought that god had another destined for the man he loved hurt more than he could imagine.

"And how exactly do we find a cupid Cas?" Dean asked really not wanting the answer to that question.

"I can go to heaven and see where they are." And with that Castiel stood preparing to leave.

"Wait. We need to think about this." Dean panicked. He didn't want Cas going off to try and find his soulmate. He wasn't sure he really wanted to find her.

"Why?" Castiel asked. He knew why he didn't want to go but this was the only way to save Dean so he would do it.

"Well, I don't know perhaps I'm not ready to find my soulmate." Dean replied sulkily, why was Cas so keen to go do this? And Castiel heart leapt slightly at that sentence.

"If is the only way to save you Dean I do not think we have choice." Sam replied calmly, he thought he could understand Deans worry. He didn't want a relationship. Every time he got close to someone something happened to them.

"Of course we have a choice. "Dean argued with him.

"What you want to stay like you are?" Sam argued back. Was Dean really that much of an idiot?

"There has to be another way." Dean said through gritted teeth.

"Well we haven't found it yet. I say Cas goes and finds cupid while we keep looking." Sam replied crossing his arms at his brother.

"Fine. But no promises." Dean said grumpily knowing that Sam was right.

"Fine." Sam sighed knowing that was the best he was going to get out of Dean for now.

"I will see you all soon." And with that Castiel left to go to heaven.

Throughout the whole conversation Claire had just sat there thinking. How would Castiel react to Dean having his soulmate with him? How would it change their family to have another person with them? She wasn't sure she truly wanted to find out the answer to those questions though it looked like she would soon.