The Non-Mixy Nature of Magic and The Key

Author's Note: This piece of work takes place after season 7 of BTVS and AU for HBP. This was written for the Harry and Dawn's Groundhog's Day challenge at Twisting the Hellmouth.

Disclaimer: Harry Potter and Buffy the Vampire Slayer belong to JK Rowling and Joss Whedon respectively. I merely dabble in their respective sandboxes.

Chapter 1

Dawn was bored. She was attending classes at Oxford and running errands for the New Watcher's Council in London on the weekends. By running errands, she meant picking up books, weapons, and spell ingredients. She certainly hadn't gone on a single patrol since she'd started at Oxford months ago. She wasn't allowed to help with any of the research either. Being the younger sister of the senior slayer sucked big time.

Dawn walked up the stairs to the entrance of the London office with her latest parcel. She saw Giles standing with an elderly man dressed in strange clothing, probably a magic user of some sort. Giles looked up from his conversation and waved Dawn over.

"Dawn, I'd like to introduce you to Professor Albus Dumbledore, Headmaster of Hogwarts School of Witchcraft and Wizardry. Professor, this is Dawn Summers, she's formerly of Sunnydale and is currently a student at Oxford University. She's the younger sister of one of the senior slayers, Buffy Summers."

"It's a pleasure to meet you, Professor."

"Please, call me Albus."

"Dawn, I know you've been looking for something to do that is more suited to your talents and experience," Giles began. "Professor Dumbledore has asked the Council to send a representative to Hogwarts to guest lecture about Vampires, Demons and other 'fun' of the Hellmouth variety. Perhaps you would find this a task better suited to yourself?"

"Not that I'm not flattered but how will your students take being lectured to by someone not much older than them, Albus?" Dawn asked.

"My dear, you will find that students at Hogwarts will be quite welcoming once you have established that you know what you are talking about. I fear that we have had a bad run of Defense Against the Dark Arts Professors and that this year's Professor has not lasted nearly as long as his predecessors. Hogwarts would be honored to host someone as knowledgeable as yourself for a couple of weeks."

"In that case, I would be delighted. Giles? Could you invent a family emergency for Oxford that would require my presence elsewhere for a few weeks?"

"I'm sure that I can come up with something suitable." Giles replied frowning.

"Excellent. Here is a Portkey that will take you to Hogwarts. When you are ready, grab hold of the Portkey and your belongings and say 'Willy Wonka'." Albus informed Dawn. "I hope to see you at Hogwarts tomorrow morning. Good day Mr. Giles, Miss. Summers."

…

It takes Dawn a couple of hours to pack everything that she thinks she will need. She takes a final look at her apartment, takes a deep breath, "Willy Wonka". She feels the unfamiliar sensation of a hook pulling from behind her belly button and is gone. She lands in a flash of green light on top of a Hogwarts student with messy black hair.