"Dean, what is going on?"

Castiel watched the brothers curiously as Sam leaned over the seat and spoke to his brother. Dean was focused entirely on the road before him as he ignored the speed limit.

"Kate – Agent Forrest – isn't from the FBI."

"She told you that?"

"No, but no one running from angels would keep a stable job," Dean remarked. "She's got to be a hunter."

"Why would angels be after a hunter?"

Sam turned his head to look at Cas as Dean glanced at the angel through the rearview mirror. Cas met both of their gazes before shaking his head in answer of their unspoken question.

"I know of no reason why this Kate would be sought after."

"Well, she went running for the hills the second I mentioned the possibility of an angel being here," Dean remarked.

"How do we know if that's her real," Sam pointed out. "We can't figure out why she's trying to hide if we don't know who she is."

"The angels are too preoccupied with fighting each other to worry about one human," Cas informed them.

"Maybe she's not human."

The car rang with silence at Sam's suggestion. Neither Dean nor Cas knew how to respond to the possibility. Dean suddenly turned to Cas, but the angel shook his head again.

"There would be no reason for us to hunt down a monster or a demon. That has always been the responsibility of hunters."

"Leading us back to square one," Dean muttered. "Do you think she could be the one killing people?"

"What would that make her, though?" Sam asked. "I mean, what's scaly and torches the inside of its victims?"

"I don't know," the elder Winchester answered, before realizing he had lost the Catalina. "Damn it! She's gone."

Sam glanced around as Dean slowed down, all three searching their surroundings for the car. It only took a minute for Sam to notice the burgundy car pulling into a parking space at the hotel before them.

"Dean, there."

Dean nodded as he spotted the car and turned into the parking lot as Kate got out of her car. He pulled in behind an old van from the 70's that was just big enough to hide the Impala, watching her intently.

Kate leaned into her car and dug around in her glove box, her tie lay discarded on the passenger seat. She pulled out a handful of silver and iron rings before slipping them onto her fingers. As she still wasn't sure what they were going up against, she figured she couldn't be too prepared. She shut the driver's side door and walked around to the trunk. Unlocking the false bottom, Kate dug through the rows of weapons and odds and ends she occasionally needed before pulling out an angel blade and a gun.

She stopped moving for a minute, the cool metal of the blade making her blood sing. The heartbeats of every human within a half-mile radius hummed softly in her ears. How long had it been, she wondered, since she last killed? Two weeks, maybe three? Taking a deep, shuddering breath, Kate tried to force away the small part of her that whispered how easy it would be to pick someone in the hotel. She was hyperaware of three people not too far from where she stood.

Tonight, she thought as she grit her teeth. She didn't want to hurt anyone. And there was a monster to be killed that night. That would slake her lust for a while. She gave another sigh and shoved aside the thoughts of the people around her. Tucking the handgun into the waistband of her pants and the blade into the inside pocket of her jacket, she focused on her task.

Sparing one last glance around, Kate locked up her car and walked out across the grass towards the tree line. It was already dark, the only light coming from the waning moon, but she could see well enough. She pulled out her phone and sent two words: I'm here. The soft sound of footsteps caught her attention and she spun around. She couldn't make anything out through the maze of trunks, but there didn't seem to be anything there.

Sam peeked back around the tree trunk as Kate turned around and continued walking. His hand tightened on the angel blade he held and the three made their way after her. A hand on his shoulder caused Sam's attention to snap back to his brother. Dean's gaze was on Cas, who had gone still and had turned his head up to the sky. The angel's blue eyes were narrowed as if looking at the sun.

"Cas?" Dean breathed, hoping for an answer.

The angel disappeared, the soft sounds of wing beats following him. A wordless exclamation sounded above them and both boys ducked as two bright streaks of light crashed into the ground before them. They stood up quickly, arms at the ready, to see Kate picking herself off the floor as well.

Cas stood with his backs to them, blade in hand, as he faced down a man who looked vaguely familiar. It took Sam a minute to recognize the man Kate had said was her partner the morning before. But he wasn't simply imposing that night. Though it was only a fraction of a second before he attacked Cas, the Winchesters noticed how his blue eyes changed as they began to glow golden.

"Oh, Hell no," Kate snapped, pulling the blade from her jacket and running towards the two angels.

Sam and Dean stood, shocked into stillness, as the woman grabbed Cas by his coat collar and dragged him off Zack. She spun him around, driving the gleaming knife towards his chest. Cas blocked the blow and pushed her aside, sending her colliding into a tree trunk. Apparently, that was only a mistake, as Zack immediately became enraged and skewered Cas through the shoulder.

"Cas!" Dean yelled, leaping to his feet and after the two.

Sam cursed under his breath, running after his brother. Zack had just pulled his blade from Cas's shoulder when the Winchesters converged on him. Before Sam could slice into the angel, a hand closed around his arm tight enough to bruise him. He turned to see Kate, but was surprised to see glowing silver eyes instead of her usual brown.

"Don't touch my angel, you bastard," she growled, her fist colliding with his cheek.

Sam tumbled backwards, groaning as he collided with what seemed to be a fallen tree. Rough bark dug into his back as she advanced on him, her movements too quick for a human. His vision swam for a minute, giving Kate enough time to grab him by collar and pull him up. He caught a glimpse of Dean struggling to hold his own against Zack over her shoulder before she slammed him into the tree behind them. Sam groaned in pain, his hands scrabbling at her wrists as she closed her fingers around his throat.

The pressure disappeared and he slumped down to the ground with a wheeze. He blinked rapidly until his vision cleared, revealing Cas holding Kate to his chest. She was still facing Sam, but her eyes were focused on the angel behind her as she tried to keep the angel blade from piercing her skin. Her hand slipped a millisecond and the tip pressed into her throat, causing her to cry out.

Ten feet away, Zack froze just as he made to kill Dean. All three turned to look at Cas and Kate. A look of thinly veiled fear flickered through the other angels face before he dropped the angel blade and schooled his features into a look of calm.

"Castiel, brother," he said softly, an almost pleading edge to his voice. "Let her go."

"Who are you?" Cas demanded.

Disbelief overcame Zack's face, "Surely Naomi did not erase me completely. Minds can be rewritten, but never completely."

Cas narrowed his eyes at the angel, "What are you talking about?"

Dean and Sam exchanged glances at the conversation. But they decided it was a wiser move to simply listen.

"Don't you remember me?"

The Winchesters flinched slightly as a brilliant light filled the woods. Sam could have sworn he saw the shadow of six wings on the ground as he squinted. The light died down and they were able to see the clear confusion on Cas's face.

"That's impossible. You cannot be real."

"You know that isn't true," Zack said ruefully. "Do you still not remember? Think back to a beach. The world was empty then. We walked on that beach thoughtlessly until I stopped you where you stood and told you, 'don't step on that fish, Castiel. Big plans for that fish'."

Cas grimaced slightly, as if the memory was painful to recall. Zack took a cautious step forward.

"Let me help you," he said. "Just let her go."

Cas hesitated, though he didn't let go of Kate. She glanced back at him through the corner of her eyes, which were once again brown.

"Do as he says, Castiel," she said, her voice edged with something Sam couldn't name. "Let me go."

Cas's blue eyes seemed unfocused as she spoke and he sluggishly dropped his arms. Dean stared at him incredulously.

"Cas!"

Cas blinked slowly, his expression changing from complacency to bewilderment. But Kate was already at Zack's side once more. The older angel looked over her carefully before speaking in a flowing language that sounded vaguely like Enochian.

"Ils nonco vohri chdr zamran gah io," he hissed in a patronizing voice. I thought you said it's only been a week.

"Vin maasi abramg balit. Zora vohim," she replied with a noncommittal shrug. It's been closer to three. That's progress.

Zack gave an exasperated groan, but the conversation was cut short as Dean snapped.

"What the hell are you two?"

"How can you travel with an abomination?" Cas demanded, looking to Zack.

Kate's attention snapped to him, "Watch yourself, seraph. My patience isn't exactly saintly at the moment."

"Enough," Zack said, tone commanding. "She is under my protection, Castiel. You will respect that."

"You would protect this…this monster?"

Sam looked between the two angels as both looked equally irate. But then he noticed Kate. She looked enraged for only a second before a look overtook her face that he knew very well. There was a sort of helpless acceptance in her eyes and she looked away from Cas.

"Kate?" Sam said. "What are you?"

Kate turned her attention to the youngest Winchester, ready to shout out a retort for the question. But she stopped when she saw how he looked at her. It wasn't in anger or confusion or disgust. He looked at her in the same way he looked at the friends of the victims they questioned on other hunts: with a quiet understanding. The barbed words died on her lips and she contemplated actually giving him the answer.

"She's a Nephilim."

Kate flinched slightly at the word, acknowledging the hard edge in Cas's voice as he said it. But she seemed cold and withdrawn in the next minute as if she wasn't truly there. Zack placed a hand on her shoulder, though it was difficult to tell if the gesture was meant to hold her back or comfort her. Both Sam and Dean stiffened at the term, recognizing it from their research earlier. There hadn't been much on the subject, but what was there wasn't pleasant.

"This is a conversation best held elsewhere," Zack pointed out, his steely blue eyes on Cas.

"Where would you suggest we go?" Cas asked, though the words were dripping in distrust.

The older angel cast a glance towards the Winchesters before returning his attention to Cas, "Follow me."

In the blink of an eye, they were gone. No sign of their presence there remained in the woods. Though a few stray hikers would wonder at the strange indentions in the trees, no one else would know that two Hunters, two angels, and one Nephilim had stood there previously.