"I swear, Hermione, your cat's got it in for Scabbers! The poor rat's fur is falling out. He's going to die of fright!"
"Ron, really, Crookshanks is a cat! He doesn't know any better. If you're so scared of him dying, then why don't you take better care of him?"
"I do!"
Harry stared straight ahead as his friends bickered on either side of him. This argument had been going ever since Hermione brought home her squashed orange cat from Diagon Alley. He wished they'd just stop and he could have some peace.
Ron and Hermione still at each other's throats, the trio walked down to Hagrid's house. Harry was determined not to add to the tension with his dementor troubles.
Harry put up his hands, silencing his friends. "Who-" He pointed toward the Whomping Willow. "-are they?"
"I dunno," said Ron, leaving the cat vs. rat argument. "New teachers? Why's she wearing overalls?"
"They must have apparated in," said Harry. He and Ron rushed ahead to investigate the bewildered visitors.
"How many times do I have to tell you?" Hermione said, exasperated as she jogged to catch up. "You can't apparate in or out of Hogwarts. Honestly, do you boys even read?" She stopped short in front of the time travelers, nearly plowing into Rose.
Rose nudged the Doctor, but he was still looking around in awe. She sighed, and introduced them. When Hermione was about to respond, the Doctor snapped out of his daydream. "Oh no, don't tell me. The Golden Trio, it's always you three. The brightest witch of her age-" Hermione looked rather flattered, "-the chosen one-" Harry grinned. He was the chosen one, after all, "and our king!" Ron looked around- could he have meant that for someone else? The Doctor studied the three, finally stating, "Third year, Sirius Black's on the loose, and there's a nice bit of time travel towards the end. Loved that bit, never saw it coming." The Doctor looked at Harry and Ron, amused. They stared back with complete confusion. "Hogwarts, eh? Oh, this is brilliant! Rose, didn't I always tell you how much I wanted to come here?"
Rose was skeptical. Sure, Hogwarts was great, but it was fictional. She'd caught bits of the movies on the telly, but that's all. It was impossible for them to be here.
"But, Doctor, I hate to ruin this, but we can't be here. Hogwarts doesn't exist."
"Well, of course it doesn't! Not in our universe, anyway. But J.K. was so brilliant, she tapped into a parallel universe to write her books. Hogwarts exists here just as much as you and I in our universe. We must have jumped a dimension when the TARDIS… well, apparated."
Rose shrugged. She'd faced Daleks and ghosts, surely she could survive a day with witches and wizards.
Hermione cut in, "Excuse me, it was nice meeting you, but we've got to go! I've got my Arithmancy exam at nine, and Harry and Ron have Divination." She glanced at the boys, who were about to protest.
Rose waved them away, Hermione walking at a determined pace up the hill, leaving Harry and Ron to anxiously look behind them as they hurried after her. Rose turned to the Doctor, about to process this turn of events. The Doctor stared after the trio, saying, "Did they just say their Divination exams?"
"Yeah. Does it matter?"
The Doctor turned to face Rose. "Harry's Divination exam. It's when Sybil Trelawney made her first real prediction. Well, second. Her first was-" His face brightened as it usually did when he explained something from his many fandoms. Rose usually enjoyed these, but today, they didn't have time.
"Doctor?" said Rose, exasperated. "Why's Divination so important?"
"It's when those three meet Sirius Black!"