Authoress here.

Ooh, how exciting! The start of another whole new story! Gives one the tingles, right? Know what else gives me the tingles? Listening to country music and J-Pop playing at the same time....Weird.

If you haven't read the three installments in the Yujo Chronicles before this one, here are the summaries:
Emiko's Story

Kurama, in his human form, starts remembering his mate from when he was Yoko, his fox demon form. Her name was Emiko, and Kurama didn't know if she was still alive or not.

A supposedly human girl from his school starts acting strange, and Kurama is given reason to believe Emiko is alive, only now inhabiting a human girl's body.

Hiei reads her mind, awakening her memories of her fox-demon form. Emiko, now in the human form of Komiko Ishitono, and Kurama are reunited.
Katsuko's Story

Yusuke is delivered a hard blow by Kaiko, who dumps him. Partly to get back at her, Yusuke agrees to model his classic "bad-boy" look for a pretty shutterbug, Katsuko, a.k.a simply Katsu.

After awhile, it's apparent both are developing the usual feelings for one another. To the relationship's inconvenience, a demon organization kidnaps Yusuke as bait for the rest of the Fearsome Foursome. Katsu finds herself involved, and in the end saves Yusuke's life.

Though this is usually where the heroine and the hero get together, but for the sake of not taking the rebound, the two decide to "just be friends" until Yusuke's fully over Kaiko.
Kiamo's Story

In order to make an important business venture, teen-genius Seto Kaiba must first show the owner of Hirugasashi Electronics that he can soften his harsh public image.

Seto becomes a temporary houseguest to the Kuwabara family, and starts dating Kiamo, pretty waitress and friend of the gang. Seto means to use their relationship to prove he's just like any other teen, but in the process starts to feel for Kiamo.

When Kiamo discovers his true motives for dating her, she goes emotionally haywire and Seto believes she's lost to him forever. Meanwhile, Yusuke is feeling the same as Katsu announces the modeling company she works with is sending her to France for awhile.

In the end, Seto proves his manly mettle to Kiamo in a tear jerking reunion with a little help from the wise fox-boy Kurama.
And that leads us to the first chapter of Narrin's Story. But briefly, remember the power of fiction and pretend wherever the Wieß Kreuz boys reside is relatively close to Sarasaski...

Also, forgive my lack of knowledge of Wieß Kreuz; I've only heard of it, and never have seen it. But, my friend for whom this story is for adores Aya, so I pulled some creative strings to make it work. Aya gets some mysterious knowledge I'm sure he's never had...but...yeah.
Yujo Chronicles: Narrin's Story

Yusuke sat moodily in the Kuwabara's living room. Shizuru had offered her guests a round of sodas, and the others sat sipping them and talking, waiting for Kuwabara to find the video tape Koenma had sent him.

Kurama glanced at his friend's surly face. "Why so intense, Yusuke?"

Yusuke glared at the demon. "None of your business."

Emiko, Kurama's mate and also a fox-demon reincarnate, giggled a little. "Katsu couldn't call today. That's why."

Hiei smiled, a rare thing for the fire-ice demon. "Aw, Yusuke, how cute."

"Shut it, Three Eyes."

"Guys, here it is!" Kuwabara stumbled into the room, almost tripping over Boton's legs. He righted himself and inserted the tape.

A few seconds of fuzz, and then the image on the television cleared. Koenma was sitting at his desk, hands folded importantly.

"Finally. I was wondering when you'd get around to watching this."

"Wha-?" Yusuke started, but the Koenma on the TV interrupted him.

"This is live, Yusuke. I can hear you all, and talk back. So watch your mouths!" Koenma, in the preferred toddler form, waved his arms around as if he was throwing a tantrum. Boton rolled her eyes.

"What's so important, then?" Hiei said irritably.

"Quiet, you." Koenma snapped. "I have a real situation on my hands, that-"

"That you want us to take care of for you, so Daddy doesn't give you a spanking." Yusuke cut in.

"QUIET!!" Koenma shouted. "I should kill you for that. But, unfortunately, I need you. A country's been invaded by a demon."

They exchanged looks. "Yeah, that's bad." Boton said.

"What do we have to do?" Kuwabara asked. But the toddler wasn't paying much attention. An ogre had just rushed into view, and handed Koenma a piece of paper. As he read, his eyes grew bigger.

Kwuabara fidgeted. Koenma slowly looked up from the paper.

"So...?" Yusuke raised his eyebrows.

"Yusuke, it's worse than I expected." The toddler prince of Spirit World was grave, speaking gravely around his pacifier.

"Spit it out, Koenma." Yusuke said impatiently. "You said earlier that a country was under threat of a powerful demon. What the hell is worse than that?!"

Koenma took a moment to glare at the Spirit Detective before continuing. "She isn't a demon. She was a goddess. And, the people don't even suspect anything wrong, for her magic is enough to befuddle the nation into believing she is their rightful Queen."

"Whaddya mean by WAS a goddess?" Yusuke asked.

Koenma shrugged. "All it says here from the information most recently gathered is she was once a goddess. A lesser goddess, but a goddess nonetheless. But that's not what I'm most worried about, as she should be only as powerful as a quest class demon. The five of you combined should take her down easily."

He paused, eyes judging Yusuke's reaction. The Spirit Detective's face was passive. Kurama, Emiko and Hiei exchanged a quick glance.

"Yusuke, the problem is the country the goddess is currently taking over is France. Katsu's right in the middle of everything."

...

"Hello, and welcome! How may I help you today, sir?" Omi Tsukiyono said cheerfully to the stranger in front of the counter.

The stranger was none other than the "adult" version of Prince Koenma, son of King Yama, ruler of the Spirit World. He cleared his throat and tried to peer around Omi to the backroom of the floral shop.

Omi saw the stranger leaning to look over his shoulder, and moved to intercept the man's gaze. "May I help you, sir?" He asked again.

"I'm looking for an...Aya..?" Koenma raised an eyebrow in question. "I was told to tell him 'White Flag,' I believe it was."

Being the prince of Spirit World had its advantages. Koenma could watch anyone at any time, and it often proved helpful. This case was no different. 'White Flag' was a sort of code phrase, used to get one of these apparently experienced fighters onto a cause.

Omi's eyes widened briefly. He bowed slightly, and turned to enter the backroom. "Just a moment, sir!"

The cheerful seventeen year old disappeared into a short hallway, making Koenma scowl. He hated waiting for anything. Peering around, he felt his eyebrows rise of their own accord.

What sort of fighters run a floral shop? Koenma wondered. Then he remembered his own employee, the forbal-inclined Kurama and his mate, Emiko. Mustn't judge a book by its cover.

"Here he is, sir!" Omi's voice brought Koenma back to his present task. He eyed the man following Omi, inwardly approving. The man was lanky, but well-toned with muscle. His face was fair, but his eyes were devoid of weakness. Shocking red hair fell carelessly into his face, and the man didn't bother to push it away.

"Aya, I suppose?" Koenma asked.

"And if I am, why do you believe you have the right to ask for me?" Aya shooed Omi away with a flick of his hand. The younger man hesitated, then walked back into the hallway.

"Because." Koenma said icily. "You and I have much in common, if all I hear about you is true. An underground demon slayer, eh?"

Aya didn't show it, but inside he cried out in surprise. Indeed, he had met and killed demons before; demons working for the man who murdered his parents and laid his dear sister to her comatose state. "Correct. What does that have anything to do with you?"

Koenma almost laughed. "Has any of these demon friends of yours mentioned a Spirit Detective at all?"

Aya's eyes narrowed. "And if they have..?"

Koenma spread his hands in a peaceful gesture. "I am here for your help, not for a fight. I don't doubt I'd get my rear handed to me if we did, and that's something I try to avoid." He cleared his throat importantly. "The reason I bring the Spirit Detective up is he works for me."

Aya's face registered recognition, then quiet disbelief. "So you claim then that you are the one from legend, Prince Koenma?"

"He's brighter than he looks." Koenma shot back. "Yes I am, and shame on you you didn't realize that in the first place!"

Aya snorted. "I've also heard the Spirit Detective is weak, and his employer is weaker."

"Dare you to say that to his face." Koenma said airily. "Sure, he was little more than a punk when he started, but he kinda had to learn quickly."

"Why are you here, your Highness?" Aya said, sarcasm dripping in his voice. "Surely not just to chat about the demons I've met."

"Of course not." Koenma sputtered. "I need your help. My Spirit Detective and the others will take care of most of the work, but none of them are either fluent in French as rumor says you are, and none of them have been out of Japan. In the Human World, at least.

"I need you to go with them to France. A little problem has started there that has the potential to evolve into a huge problem. In order to bottle this up quickly and efficiently, my people must blend in. It'll be your job to translate and get them around quickly and quietly."

"And why should I do this?" Aya leaned back against the counter. "You've given me no incentive."

"And you interrupted me." Koenma challenged. "I was getting to that." He paused for the effect. When Aya started to glare, he hastily continued. "I will grant you something I know you've been long in wanting."

"And..?" Aya prompted, getting curious despite himself.

"Your sister's safe awakening."

"You can do that?" Aya gasped.

"Of course!" Koenma said haughtily. "I can do a lot of things, except make a blundering teenager fit in with the crowd. Do we have a deal?"

Aya took the hand Koenma offered him. "We do."
End chapter

Authoress here.

Sorry, the chapter was shorter than I like to make them. But it just felt AWKWARD! I need to do more research on Aya and Wieß Kreuz before I start meddling around with the story a little more.

If you (reader) know anything useful I might need to know about him, let me know in your review. Give me your email (if I don't already have it) and I shall plead for help.

If you do, not only will I give you a cookie and a pat on the head, I shall be sure to include you in my next chapter for the well-deserved credit.

Review away!