Disclaimer: I do not own Buffy the Vampire Slayer or Supernatural. Written for fun, not profit.

Author's notes: This is a follow-up to the first chapter/story "Grip Me Tight." Inspired by a manip/prompt by Patricia de Lioncourt. In this story, SPN is still somewhere around mid/second half of season 5; Buffy, however, is set post-Season 7.

"The Darkness in Her Eyes"

Despite the passing of years, she was much as he remembered. Only, tonight, she wasn't hunting monsters but carrying a bag of groceries. It didn't make her any less the Slayer. Her strengths didn't fade like his own. And, the normality of her errand didn't make the looming Apocalypse any less real.

Castiel stood across the street, in the shadow of an alleyway, watching her and knowing that she had spotted him as soon as she'd rounded the street corner. Even without turning to give him a glance, she knew he wasn't human. Castiel could see it in the stiffness of her body, the slight tapping of her fingers against her purse, where her weapons lay in wait.

It was time. Time to call out, speak to her, but instead he stayed quiet. Watching. Afraid to say her name. No, not afraid. Shameful. He recognized shame, and his reasons for feeling it were many.

His brothers, like Uriel, had been preparing for the End for some time before the righteous man ever spilled blood in Hell, a fact that became obvious the more Castiel considered it. Castiel continued to feel foolish for ever thinking otherwise. After he was reprimanded for saving the life of Buffy Summers, he was never allowed to take part in her affairs again, asked to leave her fate to the lower-level Powers. It embarrassed him, now, that had been so willing to simply watch her be pulled from Heaven, to simply listen to her silently pray for aid when she fought what she thought to be the Final Battle.

He had stayed silent, even when he knew her heart was breaking for those slayers who had been Called too soon, when those girls slowly began to lose their powers. Until only Buffy and her sister warrior, Faith, remained… His brothers had been adamant than this was necessary; the Powers had said reversing the witch's spell would help restore balance, a lie. Castiel saw the truth of it—if those girls had been fighting still, the seals would never have been broken. If the slayers had still been at the height of their power, they would have stopped Azazel from collecting his children.

If, if, if… Castiel knew none of it for certain, but the possibility of it made him ill. Yet another sign that he was becoming a ghost of his former self.

Buffy, pausing on the stoop in front of her townhouse, opened the door, shot a quick glance over her shoulder, then entered, leaving him outside.

Castiel took a step back into the shadows, lowering his head, a frown on his face. After watching, knowing, his brothers had interfered in the fate of the Slayer bloodline, he wished to ask for her aid? It seemed an unfair request.

But was it more unfair than asking Dean and Sam to fight the Apocalypse on their own?

Castiel had been convinced his path lay in finding his Father. Until Dean had asked him a question, triggered thoughts of her and the sudden, unexplainable belief that Buffy, the Slayer, would be able to aid them.

The creature's appearance did not take Castiel by surprise. He had been waiting for the Powers to take notice of him. He knew from his punishment that they did not like other celestial beings interfering with their champions, even to help them. Castiel readied his blade in his hand.

"Hey now—no reason to kill the messenger," a voice noted. "You're Castiel, am I right?"

Castiel turned to see a man in a bowler hat, hands raised in surrender. He was a demon. Or, at least, he had been. Castiel narrowed his gaze. "The Powers sent you."

The demon shrugged. "More like I was just in the neighborhood. I'm Whistler, by the way—well, that's what I go by lately. And you're an angel who's falling. Funny, how I keep running into those…" He chuckled to himself. "So, there a reason you're vistin' the slayer's pad, or is this a booty call thing? 'Cause, surely you're not considering mixing your champions with our champions—you know how uptight the Powers are about kids fraternizing before their time. Don't like their toys getting in your sandbox."

Castiel relaxed. "You're not here to stop me. It is as I suspected—the Powers, like my brothers, are too distracted by the Apocalypse to stand guard against interference."

Whistler gave him a crooked grin. "Well, officially that 'interference' rule is for celestial higher-ups, and I'm not sure you qualify anymore—no offense. And I suppose they won't notice you were here, if no one tells 'em. I ain't a snitch, after all."

Castiel didn't reply, staring up at the house when the lights upstairs flickered on.

"You know she's retired, right?" Whistler asked. He rolled his eyes when Castiel didn't answer. "Sheesh, do I ever land the hopeless cases—fine, you wanna ask, ask. But that doesn't mean she'll play ball."

Whistler disappeared a moment later, leaving Castiel to his lonesome. He turned to step away, pulling out his cell phone, but unsure if he should call for advice.

He heard her footsteps, only because she let him. Slayers moved quickly. He wasn't sure when she had managed it, but she'd slipped out of her house and was standing there, at the alleyway, anger darkening her eyes.

Eyes that were green, not black. He reminded himself of as much.

She opened her mouth, ready to snap at him, but her expression softened, her approach slow. "Wait—I know you…"

Castiel blinked, surprised. "Yes, Buffy. You do."

She chewed her bottom lip. "You…you're different now. You look like a…guy. But it's you, isn't it? You're the one who pulled me out of—" Her hand dropped down, touching her hip, where his handprint was once etched into her skin. "Why are you—?" Her voice broke. "Who are you?"

He glanced down, unsure of himself. Again. Doubt never became easier to bear, it seemed. "Castiel," he finally replied. "Yes. I am the one who gripped you tight and pulled you from the mouth of Hell."

He didn't expect her to take such a quick step, to grab his arm in a vice. But she did. Buffy held to him as if she knew he might fly away. "I know that name," she said, softly. "Castiel. I know that." She cocked her head. "How do I know that?"

"From Heaven."

She nodded, as if that was the answer she'd expected. "And you're an…angel?" Buffy didn't wait for a confirmation. "An angel who's been creeping outside my house all night? I mean, I already thought you were kinda pervy, what with the handprint thing..." At his confused stare, she rolled her eyes. "I'm kidding…Boy, I wish I could say this was the weirdest thing that's ever happened to me. But, no."

Her face was soft, as lovely as he remembered it being, and a part deep in side of him awoke and understood why it was Dean had tried to make him lay with a woman. The realization of her appeal left him in shock. Castiel stepped out of her grip, eying her warily. "I'm sorry," slipped from his lips. It was a misplaced apology, and he wasn't even sure to which of the many wrongs he referred.

Buffy frowned, the humor washed from her face. Back to dark, but not black, eyes. Castiel thought maybe he could see the demon in her then, and though he had no reason, he feared her.

But, when she replied, her voice was gentle. Understanding. Resolved. "You need something. So ask." The request was costly, Castiel could tell. It had been years since she'd broken away from this aspect of her life, from the great battles that had formed her into The Slayer. "You saved my life once." Again, her fingers hovered over her thigh, over the ghost of his print. "I owe you a debt."

Castiel swallowed. "You owe me nothing. But you…you're needed, Buffy Summers. If you're willing to go to war again, go to Singer Salvage Yard outside the town of Sioux Falls, South Dakota. I will meet you there in two days time."

He wanted to fly before he could see the look on her face or read her answer in her eyes, but she snorted, surprising him into remaining.

"A salvage yard? Sure, okay. Not so much cryptic as oddly direct." Buffy pointed to the phone in his hand. "And the angel has a cell phone. I can't believe I'm asking this, but do you want my number?"

The Winchesters were where he'd left them, hours earlier, and they jumped when he reappeared in their motel room.

"Dude, where the hell did you go?" Dean snapped. "You take a friggin' booty call or something?"

Castiel frowned, unsure why that was such a frequent conclusion. "No," he replied, shortly.

Sam stepped in beside his brother, still looking as worried as he had before Castiel had left them. "What happened to you?"

"I—" Castiel shook his head, realizing he would need to tell them the details later. "I have a plan, but you need to leave for Bobby Singer's house now. She'll be there in two days time."

Dean raised a brow. "Your plan is a she?"

The night was chill and the sky above clear. Castiel watched it because he didn't wish to walk back into the house while they were still arguing about the woman who would be appearing by morning.

The escape was short-lived. Sam and Dean stepped out onto the porch with him, leaving a grumbling Bobby inside.

Sam cleared his throat to get his attention. "Cas…Man, we didn't mean to run you off. But, you've got to understand what we took away from that…explanation."

Castiel turned, glancing at the two of them, both of whom were wearing tight frowns, as if they were trying to keep their anger in check.

"Mostly the part where this chick has the essence of a demon inside her," Dean pointed out. He huffed, shaking his head as if he were baffled by the idea. "You know what we went through with Ruby, and Sam's blood addiction, then you're telling us—"

"Buffy is not the same," Castiel snapped.

The men stared at him, wide-eyed, and Castiel bowed his head to amend the statement. "As I told you inside, the slayer line was created to fight evil."

"What? Like fight fire with fire? Break it down for us—please, because this is setting off all kinds of alarms in my head."

Sam ignored his brother's question, stepping in front of him, his brow furrowed in frustration. "How is this any different from what I was? You said I shouldn't use my powers, but then you're wanting to bring in some girl who—"

Castiel raised a hand to stop him from going on. "There is a difference, Samuel."

"Then explain it to me!"

Dean reached forward, grabbing Sam's shoulder, as if to ease him down. The brothers shared a glance, quieting when Castiel leaned against the support beam, as if exhausted. The angel didn't meet their eyes.

"As I told you, the slayers were created by angels in human vessels. They thought it would appease the Heavenly Powers who wanted balance in the world. My point is, though, that they were not created by demons. Yes, these girls…they carry with them the potential for great evil." Castiel paused, studying his hands with intensity. "But, only the strongest of spirit, the purest of heart, are ever chosen to bear that burden. And, they, too, are tempted as you were Sam."

Uncomfortable, he stepped off the porch, staring down the driveway past the stacks of cars, as if he might see her in the distance. "Buffy Summers was tempted several years ago. A great evil threatened the world then, too. She was told the only way to defeat the evil was to embrace the dark essence inside her. But, Buffy chose her soul, her humanity, over the true powers of the demon."

Castiel turned back to them, not wanting to meet their gaze. "Yes, she is strong. Mighty. But she's a human. I know this to be true."

Sam swallowed, his eyes wet with some memory. He kept it from his voice. "We trust your instincts, Cas, but how do you know we should bring her in on this?"

Dean took in a deep breath. "Cause he knows her. Personally."

Castiel nodded. "I caught her when she fell into Hell. And knew her well when she was in Heaven. I have seen her soul, and I know it as well as I know yours, Dean."

Castiel wasn't sure how this answer was satisfactory, but when he glanced up, both the brothers had left their anger behind, staring back at him with a shared expression of knowing. Castiel frowned, unsure of what it was they knew that he did not. Or why their opinion of Buffy had changed. His explanation had seemed inefficient, even to his own ears.

Sam shook his head, breaking the silence. "You're sure one woman can really help us with the Apocalypse?"

No threat had ever stopped her before, unless she was willing to be stopped. It was the assurance he wanted to give the brothers but Dean's grin interrupted him.

"More importantly, how hot is this chick if she's making an angel blush?"

End Notes: These two chapters/stories are meant to stand alone as a complete piece. One day, who knows, I might revisit this particular blend and expand it into a full story. But, for now, this is the end of the line, as I'm currently working on another Cas/Buffy tale that's much longer. I hope you enjoyed it. Feel free to tell me what you thought.