Title: Harry Potter and the key.

Author: Hudine I Forget

Rating: PG-13

Category: Harry Potter/Buffy the Vampire slayer crossover

Summery: After Dawn causes what seems to be a very odd event without even realizing it, an even stranger thing happens. She gets a letter one summer's day carried by an owl, in it it says she has been accepted into Hogwarts school of Witchcraft and Wizardry. She is very keen to go, and begs her sister Buffy, who eventually relents to let her go, after getting a call from Giles in England promising to look after.

Disclaimer: It's not mine! It belongs to rich people not poor penniless me who is not making a penny out of this. Only made for the enjoyment of others.

Notes: This is really set not so far into season 6 of Buffy and in Harry's 5th year. The Buffy time line has been played about with a bit to make things fit.

Spoilers: Season 5 and start of 6 of Buffy

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Prologue

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Dawn Summers is the little sister of, Buffy Summers. On the outside they look like any ordinary family. Younger 15 year old girl living with her older sister, in a town called Sunnydale in California. Their mother died earlier that year after complications from an operation to remove a brain tumor. Their father, Hank Summers, who devoiced their mother some 6 years ago; never called, not even when their mother had died, and spent allot of time in Spain with his secretary. So it was just her and Buffy, with the help of Buffy's friends: Willow, Tara, Ayna, Xander and Spike.

But all is not as it seems. In truth Buffy is really a vampire slayer. The chosen one, as the legend goes, to each and every generation a slayer is born. One girl among many, she alone who will face, the vampires, demons, and forces of darkness. Being 22 years old Buffy is one of the longest living slayers there was. For each slayer brought down another will follow. Meaning as soon as one slayer dies another is activated. Buffy herself was not activated until she was 15 years old. Like most of the slayers before her, and as you can imagine a slayer's mortality rate is not very good. Most die by their 18th birthday. Though Buffy was never truly alone in her quest. She had a guide, trainer, researcher and friend, the watcher. His name was Rupert Giles. Though Giles left her to go back to England, they still kept in contact.

Even Dawn herself was not all she seemed to be. She looks like any normal 15 year old but she is not really. She really has only existed for a year now.

One year ago there was the goddess Glorificus, who was cast out of her dimension and trapped inside a mortal boy, for being unusually cruel. She was hell-bent on getting back to her dimension to make the people there suffer. Though there was only one way to get there again though. She could only get back by steeling a key to open all the dimensions of hell into earth and going though the right portal. But the monks that guarded the key hid it when she came looking. So they sent it to the one place they felt it would be safe, and in a way that will make sure it was going to be protected by the person they entrusted the task to. It was sent to the slayer, in the form of a sister. The one thing they where sure she will guard with her life.

And that is what she did. The day came when Glory kidnapped Dawn and took her to a poorly constructed platform in a junkyard, 50ft in the air. A ceremony was preformed on her, and they cut her, letting the blood slowly drip out of her opening the gateway. That's when it happened. Buffy realized the only way to stop this from happening was for her, to sacrifice herself for her sister. Buffy leaped of the platform going though the massive energy vortex below, and was dead when she hit the ground. But it worked the gate was closed and the stars was out of alignment. It was over.

However this was not the end for Buffy. Her best friend Willow Rosenberg planned a way to resurrect Buffy from the grave. So after months of gathering the things needed, her and her girlfriend Tara; best fiend Xander, and his girlfriend Anya they cast the spell making Buffy come back to life and her soul return to her body.

Another thing unusual about Dawn is that her babysitter is a Vampire. Spike was one of the worst you could get, and still would be given the chance, but an encounter with the US Military and some experimentation rendered him harmless to humans. He can only attack other demons now without getting disabling pain stopping him from doing anything. This is caused by a chip they out in his brain, that he can't get out.

And as for the town it's self. It is not all it seems to be either. The nice name it depicts it's self is not all it seems. In fact Sunnydale, California is the spot where hell opens onto earth known as the hellmouth. This brings the general population, of vampires, daemons and other dark creatures up higher than anywhere else in the world.

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Chapter 1 - Dawn's accidental magic

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Dawn was in her room, when her sister came in.

"DAWN! What did I tell you about borrowing my favorite blue sweater?!"

"Well it wasn't as if you where wearing it!" She snapped back to Buffy totally unfazed by her sister. These days it very little can scare her.

"That is not the point." Buffy snapped back at her. "You are supposed to ask me first. It's called being polite."

"Oh. And I suppose you would ever let me if I just asked." She replied.

"Well I might have."

"Yea right."

Buffy picked up her blue sweater of the bed, and looked at it, seeing there was a pink mark on it. "Look! You even got it dirty!" She said pointing at the pink mark on it.

Dawn was so mad at her sister, she just wished the whole sweater would turn pink, with all her willpower. That's when the strangest thing happened. The sweater did turn entirely pink right before their own eyes. Both Dawn and Buffy's mouth dropped, as they saw what happened. "How the hell did that happen?"

"Dawnie, don't say hell, and I have no idea..."

"It was only a shirt... Right?" Dawn asked starting to feel responsible.

Buffy was still battled about it and forgot all about being angry with her sister. "Yea... Look Dawn you go to bed, now it's late."

Before Dawn could protest, the baffled Buffy was turned around and walking out the door.

******

Later that week Dawn found that it was not the only thing that happened around her. There was the a broken cereal bowl that dawn dropped on her foot, as soon as it fell and smashed she felt the terrible pain as one of the peaces of it stuck in deeply into her toe. She then wished she never dropped it cause it looked like it was going to need stitches. Then out of nowhere the bowl was back in her hand in one peace, and her foot was not cut. It was as if nothing had happened.

Then there was the disasters haircut she got. The hairdresser's hand slipped and cut out a huge noticeable chunk of her hair. She went home crying, wishing she had her hair back the way it was, and when she woke up the next morning it was the way it was before she gone to get her haircut.

So that's what got her, worried about it. Her and Buffy looked though every book Giles had left them in the magic box, to see if they can find an answer.

They must have been there for ages. The bell rang and a customer came in and started to look around. Anya who had now joined them sat watching the man. "I hope he is going to buy something. I hate it when people come in just to look around, and don't buy anything. It's so inconsiderate."

Dawn looked up from the book she was reading though to take a look at the tall, thin man who was looking at ingredients totally oblivious to who was in the shop. Which Dawn realized he must be, or else extremely stupid, as she recognized the man. She just wished the man's shoe laces where tied together so he couldn't run away. "Em... Buffy? Am I imagining things, or is that Ethan Rayne over there?"

"What?" She asked surprised as she turned around. Sure enough there he was.

"Who is Ethan Rayne?" Anya asked looking puzzled.

"Just the center of all evil pranks played using magic." Buffy replied. She got up and walked over to Ethan approaching from behind quietly. She tapped him on the shoulder and he turned around and tried to run. But he fell flat on his face because his shoe laces where tied together.

Seeing that made Dawn be both very shocked and laugh at the site.

"Oh yes very funny, now would someone mind letting me get up." Ethan replied.

"Sure" Buffy told him as she lifted him buy his shirt collar and dragged him to the table and slammed him down on a chair. "So Ethan what bring you here?"

Ethan winced at the pain of being forcefully slammed on a chair by someone with three times the strength of a normal human. "Oh, just thought I'd come stalk up on a few things."

"Ah. So, what mischief where you planning on getting into this time then? If your planning on turning Giles into a demon again forget it cause he's gone back to England."

"Well in all fairness I did turn Ripper into a demon that those solider boys got no hope in killing. Was going to rescue him after, needed to show him what was going on!"

"Yea, sure. Your all heart Ethan." Buffy told him back with allot of sarcasm.

"If you must know I needed to get some things to activate a portkey to go home."

"Portkey?" Buffy asked eyes looking in a disbelieving manor.

"It's an ordinary looking object that will transport you to a new location, when you touch it." Ayna answered for him. "Wizards normally use them to travel a long distance."

Ethan glanced down at the books on the table. "Having trouble with objects chancing?" He asked casually as he read one of the paragraphs.

"None of your dam business." Buffy snapped back.

"Fine. If you don't want any help from someone your holding captive, that happens to speak 15 different languages."

"15? There was me thinking you could barley speak 1." Buffy insulted.

Just to prove his point he stated to read out a translation of what was on one of the books in front of him.

"Ok smarty pants. We get the point." Dawn snapped at him.

Ethan just gave an amused smile. "So what's the symptoms? Other than people's shoe laces mysteriously getting tied together? Could be a poltergeist."

"No it's been happening to me everywhere lately." Dawn realized what she said and put her hand over her mouth.

"Ah, so it's things happening around you. Did you want them to happen in anyway?"

"That's none of your business," Dawn snapped back. "who asked you for help?"

"Well I just love taking an interest in things causing chaos you know. Gave it up myself though."

"Yea right, I bet your the one causing it!" Buffy shouted at him.

"No, no. Not me. If you want to blame someone ask your sister."

"What are you talking about?" Dawn shot back. "I'm not doing anything."

"You may not be deliberately doing this Dawn. But I am convinced it is you that is doing it. It's what is known as 'accidental magic' allot of muggle born and pure blood wizards do it before they learn to stop doing it. What I am surprised at is you didn't get sent to Hogwarts. I need to see Professor Dumbledore, this. You are doing it that often you have allot of talent. Would be a pity to let it go to waste. At that moment Ethan mysteriously turned into a brown barn owl and flew out an open window.

Buffy and Dawn looked at the window in disbelieve. "What??" They said in unison.

"What the hell is Hogwarts? What is a Muggle, how the hell did Ethan do that, and who is Dumbledore????" Buffy was the first to ask.

Anya was looking at them like they where idiots. "Hogwarts, is the best school of witchcraft and wizardry in the world. It's as old as I am. I went to it before I became a demon. Was hand picked by Slytherin himself! As for a muggle that's a name for a person with no magic in their blood, an ordinary person like Xander. Professor Dumbledore is the current headmaster at Hogwarts last I heard. He's a little eccentric but is a good and kind man. Was a Gryffindor when he was at school there though. As for Ethan turning into an owl he is obviously an Animagus ."

"What's an Animagus ? And what is a Gryffindor?" Dawn asked confused.

Anya sighed. "An Animagus is a witch or wizard who can change themselves into an animal without the aid of spells."

"I'm surprised he didn't turn into a rat." Buffy added. "So what is a Gryffindor then?"

Anya lets out a long impatient breath. "Hogwarts was founded by 4 people and their are 4 houses named after them. Gryffindor, notorious for the brave and cunning as well as noble. Hufflepuff they are loyal. Ravenclaw are the scholars, the smartest. And last but not least Slytherin the house I was in. They are well known for the devious and deceitful and will bend the rules when necessary. There has never been a witch or wizard turn dark that I am aware of that was not in Slytherin."

"Three guesses which house Ethan would be in, then. I'm betting Slytherin." Buffy muttered.