A/N: This is my part of the reason why I haven't updated my other fanfic. The prompt was part of Dhfreak's Crossover Exchange on LJ. I left it open for continuation depending on how many people like it. I would like to take this moment and thank my two beta readers, txfantasystar and DramaQueen92 for helping me with this. I greatly appreciate your help. I hope you guys like it.

Disclaimer: I don't own Supernatural or The Big Bang Theory.

Werewolves

People who turn into a flesh-eating wolf when they are asleep during the full moon.

How to kill them: A Silver Bullet through the heart

"I wonder why they asked me to look this up. It seems pretty simple to me. It's not like it takes a genius to figure this out." Sheldon Cooper said to himself, looking at his computer. He thought about it before he said, "But I guess in this case it does."

This made him laugh.

After writing the information down, Sheldon got up from his chair and headed to his room. For the past week, he had been helping two distant cousins with something out of this world. If his friends knew what he was doing, they wouldn't believe him. They might think that he had gone stark raving mad. But this was one awesome secret. Sheldon Cooper was a hunter. But just not any hunter, he was a demon hunter…a kick ass demon hunter if he did say so himself.

Though he had only been doing this for the past week, Sheldon had demon hunting down to a science. He had been helping his two cousins hunt a werewolf that had been wrecking havoc around Pasadena. He was able to track where the werewolf might be through the attacks that had occurred. When his two cousins had first approached him about it, he had argued with them until they could finally prove that werewolves did, in fact, exist….amongst other things too.

As he gathered his supplies, he went over what Dean, the older of the two cousins, liked to call 'the game plan'. He never really understood why he would call it that. They weren't playing a game at least not to Sheldon's knowledge. If they were playing one, then it was the strangest game he's ever heard of.

The one thing that Sheldon didn't like about the whole thing was lying to his friends. Every time they invited him to go somewhere, he would decline. They would always ask him why not and each time he would have a different excuse. He had even turned down a date with Penny. He had wanted to ask her out for months, but he never could understand the romantic concept of dating. Every time he had gone over what he could possibly say, it would always come out as a scientific statement. Just recently, she had finally admitted that she liked him and that she wanted to go on a date with him. But since he wasn't one to break a social contract, he had to say 'no'. She had asked him for a reason why, but he couldn't tell her. He'd started talking about random things and had to excuse himself, wishing he could tell someone but knowing that he couldn't.

After gathering his things, Sheldon got his jacket and left his room. When he walked into the living room, Penny, Leonard, Raj, and Howard were sitting on the couches, engaged in conversation. They got quiet when they saw him enter. No one said anything for awhile before Sheldon said, "See you later."

He headed towards the door, grabbed his keys, and left before anyone can stop him. The others stared at the door with wonder.

"I think we need to follow him." Leonard said which caused everyone to jump.

"Why? Apparently he's found something more important than his own friends." Howard argued, mad.

"He's also found something more important than a date with me." Penny muttered under her breath.

"Never mind that. When have any of us ever known Sheldon to leave anywhere without us?" Leonard said, trying to show them reason and a little curious to what Penny just said.

They all thought about it and realized that he was right. Sheldon wasn't one to travel alone. He feared anything that could carry germs. It was the reason why he never learned to drive. With this realization, they all headed out the door, curious about what their strange friend was up to.

After leaving the apartment, Sheldon headed down the stairs and out of the building. He continued to walk until he reached the street corner. He looked around the streets for a moment before spotting a familiar 1967 Chevrolet Impala. He pushed the 'Walk' signal button repeatedly. He waited impatiently before the green walk sign told him he could walk.

He walked to the Impala and opened the passenger door.

"What took you so long? This werewolf could be attacking while we sit on our asses." Dean, the oldest of the Winchester brothers, asked, annoyed.

"I'm sorry. But research takes awhile. You wanted to know what really kills a werewolf, I found it. We both agreed that we didn't want what happened last night to happen again. We went in with a great plan but failed to kill the creature because what you had didn't work. Thank heavens for the internet because I was able to find out what really does kill a werewolf." Sheldon said, equally annoyed. He didn't get along very well with Dean.

"Well, glad that you found it. Now what is it?" Dean asked as he started to drive.

"A silver bullet to the heart." Sheldon answered, quickly putting his seatbelt on. He really didn't like Dean's driving. He wished that Sam, the other half of the Winchester brothers, would drive. But Sheldon had quickly learned that no one dared drive Dean's Impala. Sheldon, remembering the other brother, looked into the backseat.

"Where's Sam?" Sheldon asked, curious.

"He's a few blocks away from where we're going. He's making sure that no one is around to get hurt. So about this silver bullet, does it have to be from a silver gun?"

"No, I don't think so. I don't think it matters what type of gun you use. I think it has more to do with the bullet. Do you have silver bullets?" Sheldon asked, looking at Dean.

"Yes, we do."

"Then why didn't we use them yesterday?"

"Because we didn't know what killed werewolves until today, Sheldon."

"I don't see why you couldn't look it up. I was able find the information within an hour. You'd be surprised how many websites have information like that." Sheldon said, in his matter of fact tone.

"We've been through this, Sheldon. Sam and I don't get Wifi at the hotel we're staying at."

"That's why I recommended the other hotel, but you didn't want to go to that hotel because of some reason I can't recall."

Dean sighed. This was going to be a long night.

When the others left the building, they both looked around in search of Sheldon.

"Where do you think he went?" Howard asked, continuing to look.

"I don't know. I don't see him anywhere." Penny answered.

As the minutes went by, they were slowly losing hope of spotting him. It wasn't until a black Impala went by that Raj saw the passenger. He jumped up and down to get the others' attention. They didn't notice so he pulled at Howard's shirt.

"What is it, Lassie? Did Timmy fall down a well?" Howard joked at Raj's excitement.

Raj gave him an annoyed look before pointing at the Impala that was driving farther away from them.

"He's in that car?" Penny asked, surprised.

He nodded.

"Let's follow it." Leonard suggested as they quickly ran to his car.

As they drove after the Impala, they each tried to come up with a theory as to why Sheldon was with the person who was driving.

Did Sheldon know him?

Did he know Sheldon?

Did he finally pay for a driver?

After driving for thirty minutes and arguing with Dean over 'pop culture'…again, they arrived at a forest area where the werewolf was supposed to be. Dean parked the Impala right in front of a nearby store. They both gathered what they had and got out of the car. Sam soon joined them, giving Sheldon a quick 'hi' before he said, "Area's cleared. There shouldn't be anyone near here for awhile. But we might want to be quick because there is a club nearby that will be opening soon."

"Why is it that clubs open so late? Will they not get the same business during the day?" Sheldon asked, ignoring the rest of Sam's statement.

"Because they make money selling beer and liquor to people who just got home from work, Sheldon. That's why the werewolf likes to attack public areas." Dean answered, with a tired sigh.

"Oh, well, if that were the case, why doesn't he attack a park or a comic book store? A lot of people like to go to a comic book store at night." Sheldon argued as he followed the brothers to the trunk of the car.

"Sheldon, can you please just shut up for a second? We need to go over the plan." Dean exclaimed, frustrated.

"All right then. I was just asking a question." Sheldon said, giving Dean an annoyed look.

"I know, but it's your seventeenth question tonight. Now please let's focus on the task at hand."

"Okay, I'll be quiet…for now." Sheldon said as Dean opened the trunk.

They each went over the plan as they picked out a gun to carry loaded with silver bullets. They also picked out an extra weapon just in case they dropped the gun they were carrying.

After Dean closed the trunk, they went their separate ways and walked inside the wooded area. Sheldon tried to be quiet knowing the werewolf would react to noise. He heard the occasional howl and the sound of paws and hoped to catch the beast soon before it killed someone else.

As he continued to walk, he heard a loud scream. He instantly looked towards the direction it was and ran. He recognized that voice.

PENNY!, he thought, running as fast as he could.

Penny ran as fast as she could away from the creature that was chasing her. She wondered why she stayed behind when the other guys left.

"Come on, guys. Aren't you at least a little curious as to why he came here?" she asked the others.

"I may be a little curious but I'm not that curious. As far as I'm concerned, he can tell us when he's good and ready. Who knows what's wondering in there this late at night?" Leonard argued, a little nervous.

They heard a howl in the distance.

"Come on, let's go." Leonard said, instantly as they headed back to the car.

"Well, I'm staying, scaredy-cats." Penny replied, hoping it would change their minds.

It didn't.

"We'll be at the club if you need us." Howard answered as they loaded in the car and drove off.

"Fine, leave. I'll just head in the spooky forest and find Sheldon by myself." Penny said, turning around to look at the forest.

Its okay, Penny. It's just a forest. There's nothing scary in it, she thought as she started walking inside.

She heard another howl that seemed to be really close.

It's probably just a coyote. Nothing to be afraid of, she thought, trying to stay calm.

She heard it again followed by heavy breathing. She stopped in her tracks and slowly turned around. Standing before her was a grey hairy wolf-like beast with bright yellow eyes staring at her. It quickly began to growl as it lowered its head, ready to pounce.

Penny didn't know what to do. So she did the only thing she could do. She screamed and started running.

She was trying her hardest to not let the creature catch up to her, but the beast was quick. It was closing in on her and she was terrified. She didn't notice the branch that peeked out of the ground. She tripped on it and fell face first. She tried to get back up as quickly as she could, but her body was too tired from running away to move.

The beast had slowed its pace when it saw Penny fall. It crept slowly towards her as she moved her body as quickly as she could across the ground. She found herself leaning against the tree, praying for someone to save her. It then lowered its head ready to pounce on her. She quickly closed her eyes in fear, silently crying. She heard it leap in the air and was surprised to hear the next sound….a gunshot. She quickly opened her eyes and found the beast wasn't moving nor breathing. It was dead.

She stared at it not knowing what to do next and jumped when she heard someone yelling frantically, "Penny! Penny! Are you okay?" She turned around and was surprised to see Sheldon kneeling next to her.

"Yes, for the most part, I'm okay. What the hell was that thing and why are you here when this thing was lurking around?" Penny asked, looking at Sheldon for answers.

"That thing, as you like to call it, is a werewolf. It has been the reason for the recent deaths in Pasadena. The reason I'm here was because I was looking to kill it." Sheldon answered, pulling out his pistol. It was still smoking.

"You mean you were the one who shot that thing? Why would you risk your life to do something like that? It almost killed me. What makes you think it wouldn't have killed you!" Penny exclaimed, surprised by how calm Sheldon was being.

"I know it could've killed me and I know it could have killed you if I hadn't stopped it. But that's beside the point. I'm just glad to know that you are safe. I heard your scream and I ran hoping I get here in time, which it looks like I did." Sheldon said, looking towards the dead beast.

"So you're telling me that this was why you wouldn't hang out with Leonard and the other guys and why you wouldn't go on a date with me?" Penny asked, still in shock.

"Yes, I met two distant cousins of mine a few days ago. They informed me that they needed my help finding a werewolf which I didn't believe, since there are no scientific facts to prove it." Sheldon said, drifting off the topic.

"I don't doubt that. So what made you join their search?"

"They proved it with some very graphic pictures of a human changing into a werewolf. I have them on my laptop if you want to see them." Sheldon answered.

"No, I'm okay, sweetie. Thank you though." Penny replied, not really interested in looking at pictures. After seeing that thing, she didn't want to know how someone can change into it.

Soon after she was finished speaking, they were joined by two men. Penny looked up at them and recognized one of them as the man that was in the Impala with Sheldon.

"Whoa! Way to go, Sheldon! You killed your first werewolf." Sam exclaimed, patting Sheldon on the back.

"Thank you, but I did to save Penny." Sheldon said, smiling at her.

"Wow. Hey, cutie. Want to take a ride in my Impala?" Dean asked a sly smirk across his face after looking at Penny.

She rolled her eyes and was about to rebuke when Sheldon exclaimed, "Hey! She's my girlfriend."

Penny looked at Sheldon in shock. They weren't really dating at least not to Penny's knowledge.

"You never told us you had a girlfriend." Sam said, surprised as well.
"Well, at the time, I didn't think it was important. We've been trying to hunt for this werewolf so I didn't think it mattered if I was in a romantic relationship or not. But if it's that important, Penny, these are my cousins, Sam and Dean. They are who I've been with these past few days." The Winchesters brothers waved at her.

"Hi, Sheldon has told me…pretty much nothing about you." Penny said, going along with Sheldon.

"That's good. We've been trying to hide this from the general public. Why are you even here?" Dean asked, curious.

"Well, Sheldon has been avoiding me and his friends for the past few days. So we followed him here and I was the only one who was brave enough to walk through the woods. Its how I came across this thing." Penny answered as Sheldon helped her to get up from where she sat.

"Thanks to Sheldon here, no one else will have that experience. Now if you guys don't mind. Sam and I are going to dispose of this creature properly. We'll talk to you tomorrow, Sheldon, about what happens next. You should take your girlfriend home." Dean said, pulling out an axe from behind him. He always had it on him in cases where something needed to be whacked….literally.

"But I came here with you. I don't have a car." Sheldon argued, starting to panic.

"It's okay, sweetie. Leonard and the others are at the club nearby. We'll just walk over there and get a ride from them." Penny replied, pulling him by his hand.

"Oh, okay then. See you tomorrow then." Sheldon said, waving at the brothers. They waved back before getting to work.

Sheldon and Penny walked in silence as they headed towards the open street. The one thing that Sheldon liked about walking with Penny was the fact that she didn't let go of his hand.

When they finally excited the forest, she reluctantly let go of his hand to face him.

"Why did you tell him that I was your girlfriend? We haven't really been on a date yet and you haven't asked me." Penny asked, curious.

"Well, I've been meaning to ask you out for months but I haven't had the courage. I didn't want someone to take away that chance from me especially someone who I can't really stand." Sheldon explained.

"You mean you do want to go out with me?" Penny replied surprised.

"Yes, I just finished telling you that. When you told me how you felt, I wanted to tell you and say 'yes' to the date. But I had another commitment I couldn't break. But since I don't have that commitment any more, Penny, would you like to go on a date with me?"

She didn't answer him. Instead she did something unexpected.

She kissed him.

Sheldon was taken aback by the passionate kiss. But he soon pulled her closer to him in a tight embrace. Their kiss was soon interrupted by loud cheering.

They broke apart, lips red and swollen, to look at the direction of the voice. It was none other than Howard, with a huge smile. Standing next to him was a shocked Leonard and an equally shocked Raj.

Sheldon and Penny both blushed, holding each other's hands.

"So this is what you have been hiding for the past week or so. Brilliant idea to have Penny go along with it." Howard said, giving Sheldon a wink.

"But I didn't…." Before Sheldon could finish his sentence, Penny interrupted, "Yeah, we didn't know how you guys would take it. I guess our secret is out, Sheldon."

Sheldon couldn't help but smile.

She really is a good liar, thought Sheldon, looking at her.

If they only knew the truth.