Note: I know the Doctor has read Harry Potter. I don't want to spoil this story for you, so I won't elaborate on this, but I've taken everything into account.
"What Hogwarts? You mean… Hogwarts Hogwarts?!" Rose exclaimed, her eyes widening.
"Hogwarts School of Witchcraft and Wizardry, during the famous years of Albus Percival Wulfric Brian Dumbledore himself! Yes, I mean Hogwarts Hogwarts!"
"Oh my god! No! are you serious? But I thought that was fictional?"
"Yet, look outside!"
Rose opened the TARDIS door and gasped. One dream she'd given up on was getting to see Hogwarts. And yet here it was, right in front of her. The real Hogwarts. The castle was more glamorous and magical in real life than she'd ever imagined. She looked back at the Doctor with the widest grin he'd ever seen on her face, and his face mirrored it. Just the fact that she was so happy made him so incredibly happy, himself.
"I read all the books! All of them! Up to the sixth! And I can't wait for the seventh! Can't believe I never thought to ask you about it! How is it? Is it good? Do they defeat Voldemort? Oh, goodness, I suppose since it's real I should be calling him You Know Who! Oh my god, I can't believe it was all real! I can't believe we're here!"
"Rose… I just think I ought to mention that I haven't really read the books yet…"
"But you've watched the movies?"
The Doctor shook his head.
"You've had nine hundred years."
"Haven't gotten to it. Lots to do. The whole universe to see!"
"And those books aren't worth your time?"
"I'm not saying that! Rose… Oh, don't get mad at me for that! I just haven't gotten to it yet!"
"Oh, never mind that, let's go, already! We're at Hogwarts!"
She pulled him out of the TARDIS, slamming the door behind them.
"Is this one of the years Harry Potter went to school?"
"You're the one who's read the books."
"You're the Time Lord."
"Good point. Well, let's see. We're a few years away from Dumbledore's death, so yes, this has got to be some point during their time… But why are we here?"
Rose shrugged.
"Guess we'll have to find out!" said the Doctor happily, starting to walk toward the castle. "Nothing like a good mystery!"