Disclaimer: I do not own Yu Yu Hakusho, nor do I own Harry Potter. If I did I would not be posting this for you to read off a computer screen, you would be reading it from a book(preferable hardcover, they last longer) and I, the author, would be making money from it, which I am most certaintly not.

Harry Potter and The Spirit Detectives.

Chapter One: The Mission.

Koenma handed the four detectives the paperwork concerning their new mission. They were to go to a school in Europe, and protect it from a wizard known as Voldemort. Supposedly, this wizard only needed to kill one boy and then no one would be able to take him down.

They flipped trough the folders and came across a few pictures, a girl, a boy with red hair and another with black hair. Names and bio descriptions were included.

"Now, you are to no way involve yourselves with these students." Koenma explained. "If you become involved, then you will be forced to aide in this prophecy, and that would almost certainly screw up what little progress we have made." The toddler snapped his fingers and a young woman stepped up to the desk from behind the chair. "This is Mrs. Lisa Norris; she is one of the top informants for Spirit World. She will be going with you to help smooth out any wrinkles as well as get the two of you to pass for wizards."

Hiei's red eyes scanned the woman's figure, committing every detail to memory. She was average height, slender, and had nearly no Spirit Energy to speak of. Her hair was a brown gray color, jaw length and held out of her face with a strip of gray fabric. Her gray dress was long sleeved, ad swirled around her feet. A darker gray shawl was wrapped around her shoulders. But he was curious about her eyes. They were large and lamp-like, bright green, and a pair of small wire rimmed glasses were perched on the end of her nose.

"Mrs. Norris will be taking the four of you to Diagon alley where you will be outfitted and then Yusuke, Kurama and Kuwabara, you will board the train to Hogwarts and as for you Hiei; and she will take you to the school so you may set up any extra security as necessary." He handed the four boys each an ordinary looking cell phone. "These phones are the only means of communication other than letter that you will have even Hiei's telepathy will be restricted to within the barrier that surrounds the school."

"Hold up." Yusuke interjected, "If there's a barrier, how are Hiei and Norris going to get in?"

"Hiei will take this potion." Koenma held out a tiny glass bottle full of some vile looking purple stuff. "This will transform you into an ice apparition, the other half of your heritage. Your powers will change as expected, and your jagan eye will sleep up until the point where the potion where's off. And as for Lisa, well, she won't have any trouble as she already has been going to the school for a few years as an animagus. She's the reason we have so much information about what is going on."

The toddler god turned to the girl. "Lisa, I'm counting on you to make sure that nothing goes wrong. We are only keeping the castle secured until the end of the year or until it is time for the boy to fight. Do you understand?" Lisa nodded, not speaking a word. "And you also know what to do about our last resort correct?" She nodded again. Koenma clapped his hands together briskly. "Very well, then, I'll let you all get back to what you were doing."

Mrs. Norris bowed low, before turning her back on the child sized ruler and left the office.

She led the four spirit detectives down the corridors until they reached a plain door at the end of a hall. Taking a key from around her neck, she slid it into the lick and opened the door. The inside of the room was rough stone walls, and a large fireplace that reached nearly to the ceiling, a large bonfire burning in the grate. Taking a pouch from her belt, Mrs. Norris took a handful of a shining silver powder and threw it into the flames, causing them to roar up even higher, turning a bright emerald green color.

"When you step into the grate," She said in a voice that was tinged with the barest touch of an accent, one that Kurama was unable to identify. "Take a deep breath and say very clearly, Diagon Ally. If you do not, you may end up anywhere. Understood?" the four of them nodded, "Alright then, Sir Yusuke, you first."

Yusuke stepped forward and into the flames. "Diagon Alley." He said, and vanished. Kurama and Kuwabara followed soon after. The woman turned to Hiei. "Now, you must take the potion to change you while we are here. To take it in the Leaky Cauldron is pure foolishness." She held out the bottle.

Hiei looked at the young woman as if he wanted to say something. "Do not fear Sir Hiei, I will not allow any harm to come to you. For me to do so would be immediate death by your own laws."

Hiei paused, and then nodded slowly. Her words rang true to his ears. He did not trust her, but she was not lying. He took the bottle, pulled out the stopper and downed it.

They waited for a minute, and then the change started. Hiei felt his body change; much of his battle hardened physique softened and was lost. The shape of his body was also changing; his legs grew longer, just as his torso shortened. The front of his ragged black shirt filled out, and he started to feel the waistband of his pants slip. His hair lengthened until it was nearly waist length, and changed to a light aquamarine color.

Sensing that the change was finished, Hiei pulled up the waist of his pants over his shirt, and tightened the belt to fit his new size. Slipping out of his now too large boots, he re-tied the bottoms of his pants so they ended about halfway up his calves. Taking the white scarf from around his neck, he folded it and tied it over his hair.

Mrs. Norris smiled at the little demon's new appearance. "…Very nice, you should leave your boots and sword here. They will be unnecessary in Diagon Ally. Koenma will send it and any other items you may need ahead, so do not worry." She waved a hand towards the fireplace, tossing another handful of powder into the flames.

He stood in the grate and stated his destination before vanishing as well.

She watched them for a moment before stepping into the fire herself. An instant later, the flames had died back down, and the room was empty once more.

A/N: Hmm, How was that for a first chapter? The next one will involve our lovely detectives shopping in Diagon Alley, won't that be fun? Please review and give me feedback on the story, and if you would like something in particular to happen somewhere in the duration of this story, please inform me of it, and who knows, it may magically appear. One can never tell with those wizard types...