This is set around the third season of Supernatural and the time when Katherine got Mason to kill his friend. They spot some werewolf sightings and decide to check it out. I'm mixing up the species a bit. Werewolves can only turn during full moon, of course, and they transform like the VD kind of wolves—as in complete wolves. But they eat the heart like in SPN. The vampires are pretty much the VD vampires except instead of being weakened by just vervain, dead man's blood effects them too. That's pretty much the basics. You may see more differences in the actual story. Feel free to ask questions! This is written for Broodingbrothers on tumblr.

"Chicago." Dean said, looking up from the newspaper at his brother.

"What?" Sam arched a brow, returning his gaze then reaching over to take the newspaper Dean was offering him. As Sam began to skim through the news article, Dean summarized.

"Chicago." He repeated. "Four victims in one night. Their hearts were missing. Their bodies were found weeks after their actual attack." He said.

Sam nodded, setting the newspaper down and taking a sip of his coffee. "So, werewolf, then." He concluded. "And whoever is attacking these people sure seems to want to cover their tracks up or else the bodies would have showed up earlier."

Dean nodded. "Probably a werewolf. But we can never be too sure."

"So, Chicago." Dean grinned.

"It's going to be a full moon soon, Kat." Mason Lockwood was clearly worried. He had turned for the first time on the last full moon and that hadn't ended so well. He ended up killing four people and if it weren't for Katherine, he wouldn't have even known about it. She had been nothing but good to him. She was perfect. She had helped hide the bodies but they were discovered a few days ago.

"You're going to be in better control this time." Katherine cooed, reaching over and squeezing his hand. She needed him to be calm and collected. It wasn't like she cared about how many people he killed—she killed many herself—she just didn't want attention to be drawn to them just yet. She needed to keep Mason alive for the sacrifice. She sounded so sure of him—so confident and supportive. From the look in Mason's eyes, he almost looked convinced.

"B-but what if it's worse this time?" He's so vulnerable. Katherine wanted to laugh but she knew that wouldn't help.

"It doesn't matter because I'll always be here for you, Mason." She said sincerely.

"I love you, Katherine." Mason breathed, smiling weakly.

"I love you too." She lied convincingly, smiling and kissing him.

After taking a look at the bodies, Sam and Dean had confirmed that this was in fact a werewolf that had killed these people.

"Don't you think it's strange that their bodies were hidden?" Sam questioned as the boys sat at the bar of a nightclub. "I mean, when werewolves transform they have no control over their instincts. They wouldn't even be aware of who they were attacking." He took a sip of his beer while Dean took shots of vodka.

"So are you saying that someone's working with them?" Dean arched his brow.

Sam thought about it for a moment then nodded. "That would make a lot more sense than them covering up their tracks." He agreed.

"Well, that's just fucking great, Sammy. Not only are we hunting a werewolf now, but we're hunting its accomplice. Wonderful." He growled, downing another shot.

Sam sighed, biting his bottom lip before speaking again. "Do you think it's a human… or something else?" But who would join together with a werewolf? What was it that they wanted?

"I think we'll have to do some more sneaking around to figure that one out, Sam." He answered right before a bodacious blonde appeared and sat down beside him. She was wearing a dark dress that was really rather short (Dean approved of this) and the top half revealed a good amount of cleavage. Dean gave his brother a knowing look and a smirk before turning to face the woman.

"Well hey there, beautiful." He turned on the Winchester charm. "I'm Dean."

Sam furrowed his brows at Dean and looked at him critically.

"What?" He hissed back. "I'm going to get info out of the locals." Dean winked and turned back to the blonde.

Sam scoffed, shaking his head and smiling tightly before getting up and walking a bit farther away from the two. He did not want to witness his brother woo.

He was sitting rather quietly and keeping to himself when he felt a tap on his shoulder. Turning around he found that there was a man that was eyeing him a little too awkwardly. Sam's eyes widened and he stared back at him uncomfortably, unsure of what to do. "Uh… Can I.. Help you?" He asked, forcing on a smile.

"Come here often?" The man cooed.

Oh man, this was just great. Dean was over there talking to some hot chick while he was stuck communicating with a gay man that couldn't tell the difference between decent pick up lines and cheesy ones.

"I… Uh… No. I'm just visiting." He answered awkwardly.

"Tourist, huh? Where are you from?"

He wanted to gag. He wanted to get up and run as far away from this place as he could but he found that he was frozen at the bar stool. For a moment, Sam focused on the pulsing music and the glowing, flashing lights but when the man stared at him expectantly, he opened his mouth to answer.

Only he was saved. He was saved by an angel. The woman that materialized beside him was breathtakingly beautiful. Flawless, even. She was tall—and she was wearing the sexiest heels. She had long, tan legs that were barely covered at all by her blood red dress. Her eyes were the widest, brownest eyes he had ever seen and her hair was wild dark curls. He didn't know if he had ever been so attracted to anyone his entire life.

And to make matters worse, she wrapped her arms around him and whispered seductively into his ear, "Play along, I'm saving your ass." She didn't have to ask him twice.

"Hi, baby. I was looking for you." She said louder now, kissing his cheek and keeping her hands on him. Feeling slightly more confident, Sam wrapped his arms around her as well.

"I was getting us a drink, hon." He answered with a smile before glancing over at the surprise and slightly hurt gay man.

The woman turned to face him and gave him a deathly glare. "The gay club is next door." She snapped.

There was something dangerous in her eyes.

The man scrambled off.

She smirked and moved away from Sam but didn't say anything. She only watched him—okay more like checked him out. (Katherine approves.)

"Wow. Thanks." Sam laughed, reluctantly releasing her from his grip. "That was a bit rude though, I think you scared him." He teased, but laughed again.

Katherine snickered. "You're welcome. It was damn hilarious. I'm not surprised that men and women are swooning at the sight of you, though." She winked.

"Wait… plural?" He glanced around to notice that there were in fact a few looks his way.

"You're so cute." She laughed. "I'm Katherine."

"Sam." He smiled, feeling his cheeks burn a bit.

"Nice to meet you, Sam. I'm glad I got here before anyone else did—err… Well, anyone that you're interested in." She smirked.

"How do you know I'm interested in you?" He asked, a little surprised at how easily she had been able to read him.

"Did you see the look in your eyes? Or how you wrapped your arms around me? Don't be embarrassed though, the feeling's mutual." She chuckled.

"Well, in that case, I'm glad you found me too." Sam grinned at her.

"So you're not from around here are you?" Katherine asked before Sam ordered her a drink.

"No. I'm working a case here actually." Sam told her.

"A case?" She asked, looking curious.

"Yeah. FBI." He informed her.

"I see… I'm not surprised. Chicago's crime rate isn't the best." She admitted with a small smile. "I don't believe it's uncommon to have the FBI walking around in the city."

Sam shrugged. "I wouldn't know. This is my first time being here."

"Oh, is that so? Are you hear just for work or are you willing to mix in some pleasure?" She purred. "Because I'd love to show you around if you're up for it…" She raised her brows.

Sam gulped and glanced over at Dean who was giving him a thumbs up before taking the blonde with him to dance.

"My partner never seems to mind mixing those too so I don't see why not." He found himself saying.

"Wonderful." Katherine grinned, sipping on her drink.

"What about you? Do you live here?" Sam asked.

Katherine nodded. "I moved here a few years ago from my hometown." She answered.

"Where's that?"

"A little town in Virginia." She answered vaguely.

Sam nodded, getting the hint that she wasn't too keen on sharing information right off the bat.

"So do you want to ditch this place? You can come by my place…" She cooed.

"I'd love to." Sam winked.

Wow. I didn't expect Sam/Katherine's chemistry to be this explosive. I'm seriously enjoying writing this. Please review!