Supernatural Heat

Summary: Castle meets the Winchesters while researching another book in his Nikki Heat series.

AN: This crossover is for my daughter Cory. It was her suggestion when the family had a brainstorming session a few months ago. This is set after S1E6 of Castle and early seasons for SPN. Hope you guys like it as well, it was fun to write. :) Thanks for checking it out and please stay safe out there!

Disclaimer: I make no money with this.

Castle & SPN

"Hey, Beckett, where's Castle?" Ryan asked.

"I don't know, why?" Kate Beckett answered.

"Just curious, he hasn't been around for awhile. You two have a fight?" Esposito wanted to know.

"No. He's probably doing research. You know how Castle gets." Beckett replied.

"Yeah, man forgets everybody when writing." Ryan pouted.

"Hey, did he say what he was researching?" Esposito wondered.

"No, he didn't." Kate answered.

"Really? That's not like Castle." Ryan commented.

"No, it's not." Beckett agreed.

"Generally you can't get him to shut up." Esposito added.

"Aww, you miss him." Kate teased.

"No, well, maybe." Ryan mumbled.

"Yeah, who else is gonna come up with the crazy theories he does?" Esposito pointed out.

"You guys need better entertainment." Kate admonished playfully.

Castle & SPN

Richard Castle was a man on a mission. His publisher, and ex-wife, was hounding him for the first chapter of his next book, even though he still had months to go before the deadline came up for the outline. Why had he married her? Anyway, he had been at his scheduled poker game when James Patterson had mentioned something about Hunters. When the group started discussing these individuals who "hunt" the supernatural, Castle knew what his next book would be.

When James had explained that the Hunters were quite the secretive group, Castle knew his work would be cut out for him, again. How does one contact a secret group? How did these Hunters know where to go? So Castle did what he normally would do, he reached out to some of the contacts he made from Derek Storm research to find out how to set up a meeting, figuring someone would know how. He'd met and befriended a mob boss, how hard could be to find a Hunter?

It took him a few weeks to get any information and he was told that Hunters didn't like to meet up with anyone and generally only met with other Hunters at favored watering holes but Castle was determined. It would be great to have Nikki Heat hunt down a supernatural bad guy. He hadn't done that yet and knew it would be great IF he could get the information needed.

Instead of waiting for a Hunter to maybe contact him, Castle decided to do some traveling. He wasn't necessarily looking for anything but knew, with his luck, that eventually he would run into either a Hunter or something supernatural which would lead him to meeting a Hunter…he hoped. Hopefully his luck would hold out although he wasn't holding his breath.

If nothing else, he could visit a few haunted houses, abandoned buildings, ghost towns and possibly a few cemeteries to get a feel of such places. Now that he had the idea, whether he met any Hunters or not, Castle knew Nikki Heat would venture into the supernatural. Castle told his daughter about his trip and Alexis hugged him tight and told him to be careful while Martha just shook her head before giving her son a hug.

Castle & SPN

Castle drove to as many haunted houses, ghost towns, cemeteries and abandon buildings he could find which were quite a few. Who knew America had so much to offer? However, no matter where he went to, he still hadn't found anything supernatural; no unexplained sounds, no moving objects, no specters, no spirits, nothing. He had thought he had found something in an abandoned warehouse in Indiana but it turned out to be a group of kids. Maybe he should have taken Alexis' advice and stayed closer to home. So far he had driven through Pennsylvania, Ohio, Indiana, Kentucky (where he stopped at Scuffletown, a very busy place during the Civil War, but only found himself feeling chills and nothing else), Missouri, Oklahoma and Kansas before he dipped down into Texas. Now he was heading into New Mexico. Castle really hoped the ghost towns he had heard about in the state were better than his other stops.

Just after crossing the New Mexico state line, Castle pulled into a lodge for the night. He was tired and still had a few hours before his first ghost town. He checked in and called it a night. When he woke the next morning and made it to his car, Castle was upset to see someone had drawn graffiti on his trunk. Of course, having helped Beckett with the knockoff purses a smuggling ring in ?Africa? were using to smuggle fake documents in with, Castle was a little concerned. The markings looked tribal but he had no clue what they were. Hoping that wasn't the case, he looked around to see if he could see a culprit running off. As he was scanning the area, Castle noticed a black Impala parked one door down from him.

After stowing his bag in the back seat, Castle was approached by a tall blond man.

"Hey, this your car?" the blond asked.

"Yeah." Castle answered. "You wouldn't have happened to see who did this would you?"

"Sorry." The blond answered as he leaned down to study the markings, his face frowning.

"That's alright. Well, have a nice trip." Castle told the blond as he got in his car and left.

Castle & SPN

"What's up?" Dean asked as he dumped their bags in the trunk. "Someone you know?" he asked as his brother watched the car slowly pull onto the road.

"No, well, he looks familiar but that's not it, Dean. The markings on his trunk…" Sam started.

"Yeah, what about them?" Dean prompted. "Some kids get crazy or something?"

"I don't think so; I think we should follow him, Dean. He might be in trouble." Sam answered.

"How so?" Dean asked as they shut their doors and he started the car.

"I don't know, I need to check something first." Sam answered distractedly.

"So am I following him or not?" Dean prompted.

"Yeah, yeah, you need to follow him." Sam told his brother as he waited for his laptop to power up.

"Alright." Dean nodded and kept a proper distance as they followed the car from the lodge.

After a few minutes of driving, Sam finally found what he was looking for.

"Shit, Dean, we gotta stop him…now!" Sam exclaimed.

"And how am I supposed to make him stop?" Dean asked.

"I don't know, think of something. He's in trouble and doesn't know it!" Sam stated urgently.

"Alright." Dean replied as he sped up to pass the car and then started to slow down, blocking the car from passing as he did so. When they finally managed to come to a stop in the road, Castle waited to see what was going on.

"Excuse me, but you need to follow us." Dean said after he walked back to the car he blocked.

"Is there a problem?" Castle asked the young man.

"Yeah, I noticed a small amount of smoke coming out of your exhaust, not good man, not good." Dean answered, thinking on the fly.

"Is there a garage nearby?" Castle asked concerned, he hadn't noticed anything off with his car but he wasn't a mechanic either.

"Nope but I could take a look for you. There was a ranch about a mile back, we could pull off there and I'll look over your engine." Dean told the man.

"Couldn't we just pull over here?" Castle asked. If his car was smoking then he wasn't sure he should drive it any more before the guy looked it over. Of course, Castle knew this could be a set up but didn't think so, his instincts weren't going haywire.

"Not unless you want flat tires to add to it." The guy said as he looked around. "Nothin' here but mesquite and cacti."

"Oh, well, then I'll follow you." Castle conceded. He really didn't want to add anything. Yes, he had AAA but who knew how long it would take for them to get to him.

"Right then." Dean said as he tapped the roof of the car as he turned and walked back to the Impala. When he got in he looked to Sam with a question as he turned the Impala around; glad to see the man following them.

"Okay, Sammy, care to tell me how he is in trouble?" Dean prompted his brother.

"Those symbols on his trunk…" Sam paused.

"Yeah, what about them?" Dean prodded.

"Dean, they're Jicarilla." Sam told him.

"And that means?" Dean prompted.

"Well, around 1890, a chieftain, the last of his clan, cursed the white man for taking his people due to expansion and disease. He vowed to get revenge and according to lore, this chieftain appears every decade or so and targets various humans." Sam shared.

"And he's targeted our friend here?" Dean wanted clarified.

"Yes. The symbols on his trunk are symbols that would be painted for a ritual burial." Sam explained.

"Huh, well, let's see if he knows anything." Dean stated.

"Yeah." Sam replied as he ran a hand over his face.

As Dean pulled into the driveway to the ranch set a ways back, he pulled under a tree for some shade. It was a typical desert day, hot and dry. When the other car pulled up next to the Impala, all three men got out.

"Alright, pop the hood." Dean said and Castle did as he was told.

"See what the problem is?" Castle asked after a few minutes.

"Not yet." Dean told the man, actually looking the engine over to make sure nothing had been sabotaged, spirits could make some weird shit happen.

"Hey, you were at the lodge." Castle commented when he noticed Sam and realized the Impala was the one a slot down from him.

"Yeah." Sam replied as he walked to the back of Castle's car to inspect the trunk markings. "You know what these mean?"

"Nope, do you?" Castle watched the younger man, noticing his demeanor was that of worry.

Sam sighed, "Yeah, I do. Know anything about the Jicarilla Apaches?"

Castle thought a moment, "Can't say I do, no. Why?"

"Well, that's what those symbols are. You've been targeted, sorry." Sam explained.

"By what?" Castle wanted to know. He wasn't unfamiliar with danger, having worked with Beckett for a few years now but had never been targeted outside of that, this was new and, appropriate or not, Castle was excited.

Dean chose that moment to shut the hood and walk over to them. "I don't know who you are but your timing sucks, dude." Dean stated.

"Dean" Sam sighed.

"What? It's true." Dean defended himself.

"Seems to be my forte." Castle replied.

"Wait, I know who you are." Sam interjected.

"Yeah, who is he then, smartypants." Dean countered.

"He's Richard Castle." Sam exclaimed.

"Who?" Dean asked.

"You know, the guy who wrote the Derek Storm books." Sam explained.

When Dean just looked at his brother, Sam sighed, "Nikki Heat."

"Ohh, right, awesome books man!" Dean grinned widely at Castle. "Man, Sammy's read all your books."

"Glad you like them. Mind telling me what's going on? Why does my timing suck and what do those symbols mean? What am I targeted for?" Castle prodded, guessing his luck had finally run out.

"Oh, right." Sam responded and started to explain the situation to the writer.

"So what can we do?" Castle asked

"What the hell are you doing here?" Dean was very curious to why such a person was so far from home.

"Yeah, why are you here?" Sam wanted to know. He didn't deny his brother's claim that he had read Richard Castle's entire book collection because he had. He had loved Derek Storm but the Nikki Heat series was turning out to be even better.

"Well, I learned about Hunters and thought my next book would have Nikki dealing with the supernatural." Castle explained. "I think I'll call it Supernatural Heat."

"You're kidding me?" Sam asked excitedly.

"No. A fellow writer mentioned the existence of Hunters and what they do. I thought it would be an excellent plot for my next book." Castle shared.

"So you, what, want to interview a Hunter?" Dean asked, his disbelief clear in his voice.

"Yes!" Castle nodded.

"Okay, what do you want to know?" Sam asked, barely tamping down his excitement to be an information source for one of his favorite authors.

"You're Hunters?" Castle asked excitedly, maybe his luck hadn't changed after all.

"We are." Sam shared with a wide smile.

"Really, Sam?" Dean looked pointedly at his brother.

"What, Dean? He wants information, that's all. It's not like he'll name names. Right?" Sam countered.

"Right. I would change up your appearance enough that no one will know it's you then I'll give you different names. It's what I do." Castle assured them as he got his laptop out to take notes on. It would've been more comfortable somewhere indoors but Castle wasn't about to let this opportunity go by. He had finally met two Hunters and they seemed willing to share, at least Sam was.

Dean let out a "put upon" sigh, "Alright. Whatcha want to know?"

Just as Castle was about to start his many questions, Sam interrupted. "Just don't use any musical names." As he gave a look to Dean.

"What? They work!" Dean defended himself.

"Musical names? Like?" Castle asked.

"Detective Bon Jovi, Federal Agents Fleetwood and Mac" Sam stated.

"Oh, okay, gotcha." Castle nodded as he typed. "No famous band names."

"Or the people in them." Sam added.

"Understood. I wouldn't anyway, the legalities are horrible." Castle stated as he shuddered and made the Winchesters smile.

So for the next several hours, Sam and Dean answered as many questions as they could with as much detail as they were willing to give.

Richard Castle was in seventh heaven with all the information he was gathering. The Winchester brothers were quite helpful although he knew they weren't telling him everything, they were sharing enough that it would make Nikki's adventure believable. It also blew his mind how much these two men, and those like them, had faced that few knew existed.

After getting as much information as he could, Castle then realized they hadn't yet told him how to deal with the symbols on his trunk or the spirit who put them there.

"Sooo, what do we need to do so I can get back to New York?" Castle asked, excitement running through his veins. His creative juices were running over and he wanted to capitalize on it.

Sam and Dean exchanged looks, "Why don't we go back to the lodge, out of this heat, and I can do a bit more research." Sam suggested.

"Shouldn't we go to a different lodge? A hotel or motel further forward or back?" Castle asked, feeling anxious about going back to "ground zero".

"No. Those this spirit has marked were okay until they left the area." Sam reminded.

"Right, to the lodge then." Castle easily followed their lead.

When they returned to the lodge, Castle insisted he pay for the Winchesters' room along with his own, claiming it was the least he could do for them since they were saving his life.

As Sam researched the chieftain causing all the trouble, Dean took time to show Castle their weapon collection, explaining each one so the writer could be accurate in his story. Once Sam figured out what they would need for the ritual to banish the spirit and stop its revenge spree, Dean left to pick up what they didn't have, leaving Sam to chat with their new friend.

When Dean got back, he handed the candle to Sam to prep, a bag of herbs to Castle to bathe in and set the sea salt and blue sage bundle on the table.

Castle took the herb pouch with a raised brow.

"You need bathe with those for thirty minutes then let yourself air dry." Sam explained.

"Okay, what's with everything else?" Castle was quite curious.

"Well, I'll anoint and prepare the candle but you'll hold it while standing in a circle of sea salt, which will encompass your car, until it burns down then you'll bury it. While you are doing that, you'll need to make sure to clear your mind of any thoughts." Sam continued.

"So meditate then?" Castle wanted clarified. He could do that.

"Yes, then Dean will burn the sage to smudge the area as I recite an incantation to cleanse black magic." Sam told him.

"Alright. When should I take my bath?" Castle needed to know.

"The bath and drying needs to be done by eleven thirty." Dean explained.

"Why?" Castle wanted to know the significance.

"Half hour before midnight is for cleansing magics." Dean said.

"Half hour past midnight is done for harmful magics." Sam finished for his brother.

"I see, interesting." Castle nodded. "Where did you learn that?"

"Down south in Voodoo country." Dean shared.

"So, Voodoo is real then?" Castle really wanted to know.

"Some of it, yeah." Dean admitted.

"Okay, guess I'll go get ready for my bath. See you in a bit, gentlemen." Castle stated as he looked at his watch then went to his own room.

He did as he was told: tub full of hot'ish water, check; herb pouch added, check; one cursed writer submerged, check. Thirty minutes later Castle drained the water, making sure the herbs all went down the drain then stood on a towel to let his body drip dry. It was weird but he already felt better, he'd have to remember the herbs used, it was quite the relaxing bath. Once dry, Castle stepped out to return to the brothers' room when he saw them standing by his car. Walking down to them, he stepped into the salt circle where he was handed the candle by Sam before Dean closed the circle. After lighting the candle, Castle cleared his mind and tuned everything out; the last thing he heard was Sam as he started to chant.

Castle had no clue how long he was in the circle but when he opened his eyes, he saw Dean fighting a Native American in full dress while Sam continued his chant. Once the candle had burned out and was buried, Castle took the bucket of water with dissolved sea salt and a few herbs in it to wash the symbols off the trunk of his car. As he wiped the last of the symbols off, Castle watched in fascination as the spirit angrily faded away.

"Damn, he was one tough son of a bitch!" Dean exclaimed as he dragged a foot over the salt line.

"So, it's done?" Castle wanted to make sure. It had been surreal. Also, he didn't want to do anything to bring the spirit back.

"Yep, all done." Dean smiled wide.

"You used a crowbar, why?" Castle wanted clarification. It seemed a strange weapon to use against a spirit.

"Best way to make a spirit disappear for a time." Sam explained.

"Ah, I see, good to know." Castle noted.

"Yeah, but you want to make sure it's iron." Dean commented.

"Iron, gotcha." Castle made a mental note to clarify that later in his notes.

After a few minutes, they dispersed to their rooms but before the boys could close the door, Castle offered, "Breakfast on me in the morning.'

"Sounds good." Sam nodded and they turned in for the night, glad it wasn't a long drawn out process to banish the vengeful spirit for a change.

Castle & SPN

The next morning saw the three men in a diner the next town over.

"Thankless job you boys have." Castle commented.

"Yeah, but worth it." Sam shrugged.

"Someone's gotta do it." Dean said.

"Well, personally, I'm glad you are. Beckett and the boys will never believe what happened." Castle mused.

"Who's that?" Sam wondered.

"Detective Kate Beckett, Kevin Ryan and Javier Esposito, they're who I work with in New York at the Twelfth Precinct." Castle shared.

"Wait, she's your inspiration for Nikki Heat, right?" Sam asked.

"She is." Castle chuckled.

"Man, she must be a total babe." Dean breathed out, impressed.

"Oh, she is but she's also one hell of a detective." Castle proudly stated.

They finished their breakfast and headed to their respective vehicles when Castle stopped them.

"It's not much but here." Castle thrust a few bills toward the Winchesters.

"We didn't do it for money." Sam stepped back and Dean shook his head.

"I know, but, what you do, it's not something you get paid for." Castle told them.

"Beside the point, man." Dean interjected. It felt weird to take money from the writer; he was a good man and had listened to everything they had said; for the book and to save his life. It was a change of pace for them to have someone believe them and follow their instructions without a fight.

"Then consider this payment for the information you shared." Castle urged them. He really wanted to help the young men who had helped him without a moment's hesitation.

Dean and Sam exchanged looks before Dean took the money offered and shook Castle's hand. The last thing they wanted was to offend the man.

"Stay safe out there." Dean told him.

"Yeah, watch out for yourself." Sam added

"Will do, same for the both of you. The world needs you whether anyone knows about it or not."

The boys gave a nod as they climbed into the Impala and drove off, giving a wave as they did.

Richard Castle couldn't believe his luck, he had met two excellent Hunters that had not only saved his life but had been willing to share their trade. He would thank them the only other way he could, he would dedicate the next book to them and their kind and make sure no one would know who had helped him with information. He may even include his experience by having Nikki Heat go through it, with some embellishment of course.

Instead of driving all the way back to New York, Castle returned the car to a rental agency and bought a plane ticket. When he got home, he was excited to share his adventures with his daughter and mother. Of course, they didn't quite believe everything he told them but it was fun to share. Castle knew he wouldn't be able to share as much with Kate and the boys, he didn't want to cause trouble for any possible Hunters in the state but he shared enough.

"Sounds like you had fun, Castle." Beckett smiled.

"Oh, I did!" Castle agreed.

"You know, Ryan and Espo missed you." Beckett shared as she looked towards the boys.

"They did? Too quiet around here without me?" Castle preened.

"Actually, it was nice and peaceful; we got a lot of work done." Beckett retorted as she got up to leave for the day.

"Wait, what's that supposed to mean?" Castle asked indignantly as he followed her.

"Nothing, Castle, life wasn't the same without you." Kate smirked as the elevators closed while Castle pouted.

Castle & SPN

Six Months Later…

Supernatural Heat was a raving success. It had only taken Richard Castle a month to write the entire thing and turn it in. His ex-wife, er, publisher was surprised and pleased. The book had been edited and published quicker than any other book he had ever written.

The dedication in the book was:

To two of the bravest men that the world will never know.

Thank you for your time and assistance.

Without you, this book would never have been written.

Take care and be safe and know you will always have a friend in me.

~Fin~

AN: Well, that's it! Thanks for checking it out! I was curious…would anyone be interested in anymore of this crossover from me? I have gone through and figured out which episodes of Castle that they deal with the "supernatural". Would anyone be interested if those episodes were changed just a touch to include our favorite hunters helping with the actual supernatural? Let me know what you think. Stay safe and sane out there! Love to you all! :)