A/N: Hello, friends! :D Happy 2017! I'm back with another AU case!fic, set after season 11. I started writing this before I knew where the show was going to take things with Mary Winchester being back, so to keep things simple, I didn't include her in this fic. Assume that she was never brought back by Amara. ^_^ Also, no British Men of Letters, so Sam wasn't shot and kidnapped at the end of S11.

For this fic, I wanted to try something a little different... a crossover. I've never written one before, but I'm reading a series of books called Elemental Magic that I absolutely adore, and (being the crazy SPN fan that I am) my first thought was "how would Sam and Dean react to this?" So naturally, I had to write a fic and find out! ^_^ You don't need to have read the series to understand this fic, because I wrote in all the necessary explanations. If you're interested though, it's by a writer named Angela Wallace. Kinda has the same feel as Avatar: the Last Airbender or Charmed.

There's no pairings in this AU. I don't own anything related to SPN or Elemental Magic! Thanks as always to my marvelous beta reader and cheerleader, Aini NuFire. Enjoy ^_^

"Okay, so remind me again why we're not heading towards California for some well-earned time off right now?" Dean grumbled as he pointed the Impala down the highway—away from the sun and sand he'd been hoping for. After all, the Darkness was gone and the world somehow wasn't in peril at the moment.

One vacation. Just one. Was he really asking for so much?

Sam certainly seemed to think so, judging by the bitch-face he was shooting Dean from the passenger seat.

"Because we still have work to do. Remember? Saving people? Hunting things?"

"The family business," Dean agreed. He sighed, lifting one hand from the steering wheel to gesture at the world in general. "Why can't they just save themselves, huh? Just for one week. Hell, just one day off!"

Sam snorted, but didn't try to come up with an answer. Twisting in his seat, he asked, "Hey, heard from Cas at all today?"

"Nah." Dean sighed again. They actually had taken a full month off, after Amara. Not because the hunters were on a break, though. The minute things had calmed down, the brothers had put everything else on hold to focus all attention on their angel instead. Even though bearing Lucifer hadn't done any permanent physical damage—if anything, Cas's grace seemed to have been strengthened from the Devil's powerful presence—it had been a torment that he couldn't just bounce back from.

Psychologically, the angel had been scarred by his brother, but the Winchesters knew that the archangel was not the only one to blame. The cold, hard truth was that it was largely their fault Castiel had ever said yes to begin with.

Well, they would never let anything like this happen again. They were never going to let their best friend, their brother, feel like the only way he would ever be "useful" to them was by sacrificing himself.

It had taken a lot of work and all of Cas's inner strength, but both Dean and Sam felt like the angel was starting to act like his old self again at last. He finally seemed to trust that they genuinely wanted him to stay with them, and that they would do anything they could to help him on his quest to rebuild diplomatic channels between Heaven and Earth.

Not that Dean was much help when it came to "diplomacy", but he'd at least stayed involved, always asking Cas how things were progressing. The angel still lived at the bunker between tenuous visits to Heaven, and called often when he was gone, but the hunters no longer felt like they needed to be worried about him and his state of mind. He knew he was worthy, cared about, and one of them.

But apparently this major victory wasn't enough to earn them one lousy trip to the beach.

A hard-rock tune filled the interior of the car. Dean fished around in his jacket pocket to retrieve his cell phone and glanced at the display before looking at Sam with a grin. "Speak of the devil."

"Too soon, Dean."

Rolling his eyes, the hunter punched the button to accept the call and flipped on the speaker. "Cas, how's it going?"

"Dean," the angel greeted him. "I suppose that depends on what you mean specifically."

Damn, it was good to have him back. Dean rolled his eyes again while Sam snickered and called,

"Hey, Cas! Let's start with where are you?"

"Back on Earth temporarily. Heaven doesn't get a cell signal," Cas explained. "But I should return soon. Several of the main leaders are having a meeting about the organizational structure and hierarchy. I've been invited to sit in."

"Hey," Sam exclaimed, raising an eyebrow. "That's good news!"

"Yeah, I bet that one douchebag was just thrilled about that," Dean added with a snort. "What's-his-name, Matthias. He still giving you grief?"

Cas made a strangled sound of frustration. "Yes. Matthias continues to try and persuade anyone who will listen that I'm not to be trusted and shouldn't be in Heaven at all. Fortunately, voices like his are becoming fewer."

Dean shook his head, trading a scowl with Sam. "You want me and Sammy to give him a talking to in a dark alley somewhere?"

"Dean, you know how I feel about violence towards-"

"I'm kidding, Cas." For a warrior, their angel was big on the whole "peaceful solutions" thing. It irritated Dean to hear about the feathered dicks causing Cas trouble, but at the same time he was just happy to know what was going on in the angel's life. After so long of more or less forgetting about him whenever he flew off, they were determined to do better.

"Well, just let us know what we can do to help," Sam offered now, echoing Dean's thoughts.

"I will…. Thank you." They could hear the smile in Cas's voice; it felt good. "Where are you? It sounds like you're in the car."

"Yeah, we might have caught a case," Dean explained. "Not sure yet. We're heading to check it out right now."

"You are? What is it?"

In the passenger seat, Sam leaned over and grabbed a manila folder, flipping it open to scan the contents once again. "Not much to go on," he admitted. "There's a lake not far from here that was on the news last night. Apparently, all the fish in the entire lake seem to have just died, all at once, and there were four bodies found. Now there's reports of a couple more missing who were supposed to be out there fishing yesterday."

"Is it possible it's just a naturally occurring toxin?" the angel pointed out.

Dean shrugged. "Yeah, but there was one witness, some kayaker who hadn't actually gotten in the water yet. He swears up and down that the dead fishermen were drowned by some lady standing in the middle of the lake."

"Which, by the way, is over fifty feet deep," Sam added.

"That does sound more like a supernatural problem," Cas agreed. "You're thinking a water monster, or perhaps a spirit?"

"We're not sure yet," Dean admitted. "Could be lots of things. Could be nothing. Maybe the guy's just crazy."

"Do you want help? Perhaps I could be of assistance."

The hunters traded looks again. For now, they were still trying to be careful when it came to this subject of Cas being useful, and Dean grudgingly gestured for Sam to field this one. He would know what to say that wouldn't make it sound like they doubted Cas could help. Or that what they needed should come first. Or that the angel only mattered as long as he could help.

Sam, to his credit, sounded completely laidback and casual as he replied, "Eh, you know we always appreciate your help, but this meeting of yours sounds way more important. And we don't even know if this is a case. We'll handle this and you take care of Heaven, and we'll meet up at the Bunker later to trade stories. I wanna hear how it goes."

Dean approved. Giving his brother a nod, he added out loud, "And hey, don't take any crap from Matthias. I know you're turning all diplomat, but Obi-Wan still kicked ass when the situation called for it."

"Obi-Wan was also betrayed by the Jedi he was closest-"

"Oh, come on, you know what I mean!" Dean said with a groan, while Sam bit his lip to keep from laughing. It still threw them off a bit when Cas actually understood the pop culture references that Dean used.

At any rate, they could both hear the smile in the angel's voice as he said, "Thank you, Dean. Be careful. I'll be there whenever I can."

"Roger. We'll leave a light on."

"Good luck, Cas!" Sam added, before Dean ended the call.

The older hunter felt himself relax, relieved at how much better things were between the three of them these days. If only they had been doing this all along… but it was too late for regrets, and there was no changing the past. Wishing they could was just a waste of energy. All they could focus on was now.

And speaking of now… it was time to get their head in the game, figure out if there was a case, and solve it in time for supper. They had a witness to find.

SPN SPN SPN

"So, let me get this straight," Sam said, frowning over his open notebook at the kayaker who had claimed to witness the murders. "You're saying a woman was standing in the middle of the lake… and that's how those men drowned, she killed them."

"Look, I know it sounds, like, totally whacked out, dude." The kayaker scratched his head under the dirty bandana he wore. His expression was pleading, but also rather glazed. Sam mentally added a few more points to the theory that the guy was just crazy. It didn't help that his entire apartment smelled like pot; Sam hoped Dean finished talking to the sheriff quickly and came to rescue him.

"You're saying she was, what, on a paddle board or something?"

"No, man." The kayaker sighed. "I don't know how else to say it. I know you don't believe me. The cops didn't, why would the Feds? She wasn't standing on anything, she was… I don't know."

Sam tried not to roll his eyes. "And this… this woman," he went on, for argument's sake. "What did she look like? Did she say anything? If she was just standing there, how did she reach them?"

"All I know is what I saw," the witness maintained with a stubborn frown. "It was like she kinda… pulled the water closer to draw them in, y'know?" He gestured with his arms to demonstrate. "They were trying to get away, but the water just kept pushing them towards her. The waves were too strong, so… they drowned."

"Four of them. You just watched her drown four men?"

The kayaker glared at Sam, crossing his arms. "Look, buddy… I know you think I'm nuts. I thought I was nuts. What I saw…" He shook his head. "It was impossible, okay? I- I thought I was…"

"Tripping on whatever you've been smoking?" Sam supplied, taking in the glazed expression again. He sighed when the kayaker swallowed and took a nervous step back. "I'm not going to bust you," the hunter said. "If you cooperate. I need you to tell me everything, no matter how crazy it sounds."

Casting a quick look around, the witness leaned in closer so he could lower his voice. "Yeah, okay?" he whispered. "I thought I'd gotten a bad batch or something, and it wasn't real, so I came home. I didn't know it had actually happened until I heard about the bodies being found, and that's when I called the cops. But I'm telling you, she was there. Kept asking them where it was, and she wanted it back."

"Where what was?" Sam asked.

The kayaker shrugged. "She didn't say. And none of the guys she killed seemed to know. I think that's why she killed them. Hey… why are the Feds here?"

"We go where we're sent," Sam said, the automatic response to the fairly common question slipping easily off his tongue. "Is there anything else you can tell us? What she looked like, where she went?"

"Well… really pretty. Dark hair. Kinda too far away to see anything else, and I didn't wanna get close. I don't know where she went, dude. The police don't believe that she was ever here. But I know what I saw. I'm not stoned—well, I am, but she was real."

"Right," Sam deadpanned. He was starting to feel more and more relieved that they'd convinced Cas not to come. He would have hated for the angel to miss out on something so important just for this wild goose-chase. The hunter flipped his notebook closed and nodded to the witness. "Be sure you're available for more questions if we have them."

The shaggy man shrugged again as Sam nodded and made his escape out of the reeking apartment. To his relief, the Impala was just pulling up into the drive. The hunter hurried over to the passenger side and slid into the car, giving his brother an exasperated look.

"So what did the witness say?" Dean asked, before wrinkling his nose and leaning away from Sam. "Whoa… let me guess: stoner."

Sam lifted an arm to his face to sniff. Great, now he smelled like weed. The hunter groaned. "Good guess. He still thinks it was some beautiful, dark-haired woman who drowned them."

"I'm sure it was," Dean said with a snort. "Starting to think this one's a wash. Still don't get the fish, though."

"Something obviously happened," agreed Sam, as Dean turned the car back onto the road. "But like Cas said, maybe it's just some kind of… you know, toxin or something. I've never heard of a ghost or a monster doing something like this."

"Yeah, me either. Sheriff thinks it's some kind of hazard waste seeping into the lake. Which sucks… but not our kind of problem. There's some wildlife management whatever that came to take samples, so I guess it's taken care of. I say we hit the road, head for the beach!"

Sam couldn't help but smirk at his brother's enthusiasm and hopefulness. The beach was sounding better and better. But they still had to rule out every possibility. "We're already here. Might as well at least go check for EMF just to be sure," he suggested, stowing the notebook in his inner jacket pocket. "And maybe by the time we're done, Cas will be back." Sam just hoped their angel was having a more successful time of things.

Dean nodded his agreement. Once again, his phone went off with a rather obnoxious rock tune, and he took one hand off the wheel to dig for it. Sam watched with interest as the older hunter checked the number, then gave him a look.

"Agent Curry," he said by way of greeting, flipping the phone to speaker.

"Agent. It's Sheriff Warner. You said to keep you in the loop?"

The Winchesters traded looks, and Dean replied, "Yeah?"

"Just got the call. Another lake across town… same as Kansa Lake. All the fish are just dead."

"Any bodies found?" Dean asked, before rolling his eyes and adding, "Human bodies?"

"One so far. We're sending a team to drag the lake right now. But here's where it gets interesting. The man who called it in? Same cockamamie story about a lady standing in the water, drowning folks."

Sam gaped at the phone, then at Dean. A single stoner tripping out was one thing, but to have two witnesses telling the exact same story? And it couldn't have been the kayaker; Sam had been talking to him when this new development was called in. Suddenly a monster attack was seeming more believable.

"You're kidding," Dean grumbled. "What the hell?"

"Wish I was. Sounds rehearsed to me," the sheriff retorted. "Might be these guys did the drowning themselves, could be looking at a killing spree. We should grab our first witness before he can attack again."

Again, Sam and Dean shot each other a quick look. Dean raised his eyebrows in question; Sam was the one who'd done the interview, so he was the one who would know if the guy had a killer vibe. The younger Winchester shook his head.

That seemed good enough for Dean, as he replied, "The only thing that guy was guilty of is not having a prescription for whatever he's self-medicating with. It's not him. I'm heading to Kansa Lake right now with my partner, to get a feel for things. Still sealed off, right?"

"Right. I've got a unit stationed at the turn-off for the main parking lot."

"Alright, we'll be in touch."

Dean hung up and stuffed the phone back into his pocket with a huff. "I'm never gonna get my trip to the beach," he grumbled under his breath. "This had better be something, not just some crazy wild-goose chase."

Sam ignored him, his mind racing. Two lakes, opposite ends of the town, within a day of each other. Was it possible there was a natural explanation for this? An underground chemical leak of some kind could certainly explain the lakes, but then why weren't people dying all over town? Wouldn't it have gotten into the whole water supply?

"So, what do you think?" he asked out loud, brow furrowing in thought.

"I don't know, man. Ghost woulda made sense in one lake, but how would it travel to the other? Demons don't drown people. Witches… nah, that doesn't make sense, either."

"Some kind of water spirit?" Sam suggested. "Maybe even a goddess of some kind?"

"What would a water spirit or goddess be doing in some tiny lake outside some podunk town? And why kill the fish?" Dean argued with a frustrated grimace. "This is making less sense."

Yeah, it was. Sam shook his head as they piled into the car, already digging out his phone while Dean turned the engine over and pointed them across town. If it was some kind of water spirit they were looking at, or a pagan deity, they would have to narrow it down in order to figure out how to kill it. For a moment, his thumb hovered over the call button, considering whether or not to call Cas and ask him if he knew of anything like that.

But Cas was busy, and Sam didn't want the angel to feel obligated to drop everything and come to their assistance, as all the other angels had accused him of constantly doing.

No, they would figure this out on their own. Switching over to the Internet instead, Sam buried his attention in the quest for some piece of lore that would help them on their hunt.