A/N: Hello and welcome to the verse that just keeps evolving! To think that "From the Ashes" and "A Fire Shall Be Woken" was to be it for this particular AU, and then came three more sequels, and "Burn It Down" was honestly supposed to be the final happily ever after for everyone. But then came snapshots of TFW raising Cas's daughter, and then she started growing up in those one shots, and now she's fully grown and we're going to have a new series of adventures!

But I've had a lot of fun with this verse and I think the next few fics are going to be fun too. (And full of angst and hurt/comfort because, come on, it's me.) I hope y'all will enjoy it.

This takes place five years after "Burn It Down" (which would be season 16 if that helps orient you; but remember this verse went AU seasons 10-11).

Disclaimer: The boys aren't mine. Thanks to 29Pieces for beta reading, for always being my cheerleader, and for the lovely cover art! ^_^

Chapter 1

Dean came into the bunker after spending all morning in the garage working on the Impala. He'd changed the oil, given the engine a tune-up, and finished her off with a nice wash and wax that left her sparkly clean and shiny. Nothing filled him with a more inflated sense of pride and accomplishment than keeping his Baby in pristine condition.

Too bad no one else shared that devotion. Instead of helping him with this sacred maintenance, Dean found everyone in the library doing nerdy book or computer things. Cas and Ryn were looking over some ancient tome in a dead language, while Sam and Amy clacked away at their laptops. Seriously, none of them had any appreciation for craftsmanship.

Dean turned to bypass them and head to the kitchen for a sandwich, when Amy's voice stopped him.

"Uncle Dean, do you have a minute?"

He turned on his heel and entered the study area. "Sure. What's up?"

"I found a case," she announced. "A man in Nebraska mysteriously died yesterday, and a witness said they saw a cloud of black smoke. Sounds like a demon."

Sam looked up from his computer. "Just one death?"

"So far," Amy replied.

"Mysteriously died how?" Dean asked.

"Asphyxiation. While standing on the sidewalk."

Dean glanced at his brother, who shrugged one shoulder. It wasn't a lot to go on, but they'd hunted on less.

"Yeah, alright. We'll look into it." This was why he kept Baby in tip-top shape. "Good catch."

Amy stood abruptly. "Can I come?"

Dean blinked at her, a refusal already on his lips.

"I'm ready," she barreled on before he could answer, shooting everyone in the room a pleading look. "I did well on the trainings with Crowley and can handle myself in a fight. Please?"

Dean was still going to say no, but he caught Ryn's thoughtful expression, which stayed his tongue.

Ryn straightened. "I think it's time."

Dean's knee-jerk reaction was to vehemently oppose that, but he managed to hold it in. He'd known for a while now that Amy would eventually have to go on a hunt. He'd just been hoping to put it off for as long as possible. But she was grown now, and it was only natural for her to want to join them in the family business. Better she do it with them rather than getting impatient and trying to strike out on her own.

Not that that made it any easier for Dean to swallow.

"Why don't you and Cas take her on the case," Ryn suggested. "Sam and I can stay here."

Dean looked to Cas to gauge his reaction. And while the angel had been just as protective of his daughter, he had a pensive crease in his brow that suggested he was seriously considering this. Amy was practically rocking on the balls of her feet in anticipation, giving her father the puppy eyes she'd inherited from him.

Cas finally met Dean's gaze and gave a subtle nod.

He sighed in resignation. "Alright then." He turned to his niece. "You'd better put together a go-bag."

Amy's face lit up. "Thank you! I won't let you down." She went hurrying from the library toward her room.

Dean couldn't help but be proud of her enthusiasm, at least. And they had been training her; she had to test her mettle sometime.

"When do you want to leave?" Cas asked.

"After I eat and shower," he replied. He was covered in grease, after all. "Sam, you wanna forward the stuff she found to my phone?"

His brother nodded, and pulled Amy's laptop over so he could do that.

Dean turned to head for the showers. And if he didn't rush like he normally would have, well, no one could blame him.

Amy stood in front of the mirror, scrutinizing her 'FBI' clothes. She'd changed into slim black pants and a white silk blouse with a little fringe around the neckline. The suit jacket was tailored to feminine curves and hugged her frame. She turned from side to side, trying to decide if she looked the part. She'd had plenty of training in lore and the fighting side of hunting, but the investigative stuff was all theory. This would be her first time putting it into practice, and she was both nervous and excited.

There was a soft knock on her door before it opened and her mom came in. Out of everyone, Ryn was the most supportive of Amy hunting, which she was extremely grateful for. Amy kinda wished her mom was going on the case with them.

She spread her arms. "How do I look?"

Ryn closed the distance and reached out to fold down the collar of the blazer. "Like a powerhouse woman."

Amy smiled tentatively.

"You'll do great," her mother went on. "But pay attention to your dad and Dean out there and follow their lead."

Amy nodded. She turned to study her reflection again, and pursed her lips in consideration before she gathered her long brown curls up off her shoulders. Yeah, putting it up looked better. She grabbed a hair band off the nearby dresser and quickly tied her hair back.

Ryn smiled. "You all ready?"

Amy nodded again, and moved to the bed where she'd left her packed duffel bag. Kit was curled up on top of it as though in protest. Now even the cat was being overprotective. Amy nudged the feline off and slung her bag over her shoulder just as she heard Dean's voice yell from down the hall to get going.

Amy took one more deep breath and exchanged a smile with her mom, and then hurried out of the room before they decided to leave without her.

The drive from Kansas to Nebraska wasn't long, and since it was only mid-afternoon, they went straight to the morgue to examine the victim. Dean and Amy had dressed in their FBI threads before leaving the bunker. Castiel, of course, hadn't needed to change.

The medical examiner was expecting them, as Sam had called ahead to give the police a heads-up. Castiel had done this dance often enough to expect some resistance from local law enforcement, especially when they didn't believe there was even a case to be investigated. Right away when the ME came out to meet them, the man had a put-out expression on his face.

"Agents," he greeted. "As I told your supervisor, there's nothing to see here. William Stackhouse died of smoke inhalation."

Dean just shrugged. "We just go where they tell us to. But since we are here, mind if we take a look? Then we can tell our boss we did and he can stop breathing down our necks."

The ME made a slightly disgruntled noise, but nevertheless gestured for them to follow him. He glanced at Amy. "What is this, take your daughter to work day?"

"She's an agent in training," Dean replied before Castiel could, shooting him a look.

Castiel huffed silently. He was going to say that.

They headed down the corridor to the morgue where a body was laid out on a slab, covered with a sheet up to the waist and a Y-stitched gash down the torso.

"Smoke inhalation, huh?" Dean said, sounding skeptical.

"That's what my report says."

"He was standing on the street, though."

"Smoking a cigarette."

Dean arched a dubious brow. "You're saying he died of smoke inhalation from a cigarette?"

The ME snorted. "It's weird, I'll give you that. But I examined the lungs and they were full of smoke. That was the cause of death." He shook his head. "Talk about a quit smoking campaign."

Dean glanced at Castiel. That did sound strange.

"Well, we don't want to keep you," Dean said. "If you leave the report with us, you can say you did your due diligence, and then we can tell our bosses the same."

The ME gave him a sidelong look, but then begrudgingly handed over the file. "Have at it." He left, finally giving them the room to properly examine the body.

Castiel moved closer and ran his nose over the victim. He then straightened and turned to Amala. "What do you smell?"

She leaned down and gave a whiff, and furrowed her brow. "Smoke. And—" she scrunched her nose up "—lack of deodorant."

"Anything else?"

Amy grimaced as she bent closer. "Um, kidney disease?"

"Now you're just making stuff up," Dean interjected, tossing Castiel a doubtful look. "You can't smell this dude's internal organs."

"You've seen me do it before. I can tell you the state of your liver right now," he offered.

Dean held up the file between them warningly. "Don't get fresh with me."

Castiel huffed. "Would you like to confirm our diagnosis?" he asked, flicking a pointed look at the report.

Dean rolled his eyes and opened the file to skim it. His gaze stilled. "Well, I'll be damned."

Amy brightened. "So I was right?"

"Yep."

She beamed at Castiel. He smiled encouragingly back at her.

"So, what are you not sensing?" he prompted.

She frowned, and roved her gaze over the body. "Um…"

Castiel waited patiently, and a quick moment later, her eyes widened.

"No sulfur."

He nodded. "Exactly."

"So, not a demon," Dean concluded.

"No," Castiel agreed.

"But what about the black smoke the witness saw?" Amy asked.

"Well, according to this, guy's lungs were full of smoke," Dean said, reading over the medical examiner's report again.

Amy's expression fell. "So, my first case and I sent us on a wild goose chase?"

Dean pursed his lips, and handed the file to Castiel. "I'm not sure I buy it being a cigarette," he said, and pulled out his EMF reader. As soon as he waved the sensor over the body, it gave off a high-pitched beeping. His brows rose. "Alright, then. Ghost instead."

Amy blinked in bewilderment, and said somewhat dejectedly, "I can't believe I was so far off."

Dean pocketed the EMF reader. "You know how many cases we've been on that start out looking one way and end up being something completely different? It's just part of the process."

Amy sucked on the inside of her cheek. "Yeah?"

"That's why you have to rule out possibilities when investigating, rather than trying to prove your initial theory," Castiel added. "And always keep an open mind."

She nodded in understanding. "Okay, so, ghost. That means we need to go to where the victim died, right?"

"Right," Castiel replied, scanning the rest of the report for the relevant information before closing the file and setting it on one of the instrument trays.

The three of them then made their way back out to the Impala and drove to the address where the deceased had been found.

It turned out to be the scene of a burned down building. Two charred walls were barely standing on the corner of the block perpendicular to each other, the skeletal remains of the other two facing the street. Scorched gaps looked in on piles of ash and debris illuminated by sunlight. The roof was completely gone, save for a few beams that looked as though they could cave in if a sparrow landed on them. There was a bright red sign with Japanese Kanji characters piled on top of some of the refuse.

"Well," Dean said as they climbed out of the car. "This looks promising. How much you wanna bet someone died in this?"

Castiel scanned the building, senses peeled. All was quiet. There was barely any traffic on the street, and the nearby structures looked old and vacant. Not the nicest part of town, based on appearances.

Amy already had her phone out and was looking at something. "It was a Japanese restaurant," she said. "Burned down a few weeks ago…killed everyone inside."

"How many?" Castiel asked.

"The owner, three employees, and…uh-oh."

Castiel and Dean turned toward her. "What?"

She looked up, expression grim. "The fire was so hot that all the bodies were completely incinerated. There's nothing left of them."

Dean's brows rose sharply. "Great. So salt and burning is out of the question."

"There were three customers," she went on. "But the police have only been able to identify two."

"Even better," he muttered.

"What was the cause of the fire?" Castiel asked curiously.

Amy swiped at her screen a few times. "Police determined arson, but haven't announced any suspects."

Dean turned in place, scanning the wreckage thoughtfully. "Hey, wasn't our vic a real estate agent?"

Castiel remembered seeing that in the report. "Yes."

"Maybe it was him. Trying to free up the property for development or something. The ghost could have targeted him for revenge."

"This area doesn't exactly look like prime real estate," Castiel remarked.

"Okay, maybe not. But if our ghost is attached to the building, it wouldn't want someone coming in and planning to tear it down."

That was true.

Dean cocked his head. "I've never had to burn down a…burned down building before. Would that even work? Seems redundant."

Castiel furrowed his brow. "I don't know. The ghost could also be attached to an object."

Dean pulled out his cell. "I'll call the police station and have them send the arson file to Sam. Maybe he can start putting together victim profiles."

That was definitely going to be a challenge in this case.

While Dean made his calls, Castiel stepped up to the edge of the ruined restaurant and squinted, trying to sense a ghostly presence. Nothing stirred, though. He scanned the detritus inside. It was possible an object could have survived the fire and the ghost attached themselves to it after death, but searching through it all would be time consuming.

Amy came up beside him, and they both stood in silence for several long moments, just observing.

"I don't sense anything," she finally whispered with a slight inflection, as though asking whether she was right or not.

"Neither do I," he replied.

She was quiet for another minute, Dean's voice in the background.

"So," she said. "We've got a lot more work to do, don't we?"

Castiel nodded. "Yes, we do."