A/N: Part of my one year of writing challenge. Prompt taken from Reddit: Fix the biggest plothole in any story of your choice. I don't own any of these people.
"Hang on a second," Ron said, looking a bit confused. "You're telling me that the Ministry of Magic gave you the power to turn back time, and you've been using it to take extra classes?"
"Of course," Hermione replied, looking as if this was a completely normal way to utilize time travel.
"Bloody hell!" Ron exclaimed, throwing his arms up in the air. "Why don't we just use it to go back in time and stop You-Know-Who from coming into power?"
Harry and Hermione stared at him, slack jawed.
"You seriously haven't thought of this? You're supposed to be a bloody genius, Hermione!"
"Well," Hermione responded, "It might've crossed my mind." Ron let out a snort and she shot him a glare. "But what I've been doing is dangerous enough! Horrible things can happen to wizards who meddle with time!" She turned a beseeching glance to Harry. "Can you talk sense into him?"
Harry's eyes were still wide, his mind ablaze with the possibilities. "Maybe he's got a point," he said. "Why couldn't we?"
"Harry," Hermione began, but stopped short when a strange noise sounded. The trio looked around the room, searching for the source. It seemed to be a mechanical sound, but very wheezy and groany.
Suddenly, a police box materialized in the room. They stared, flabbergasted, as a tall, skinny man in a suit bounded out the door of the box.
"Hello!" the man called cheerfully, striding over to them with his hands in his pockets and a broad smile on his face. "I'm the Doctor! I overheard your little conversation. My TARDIS," he indicated the box he'd just exited, "Sometimes she picks up on things that might need my help! And you three certainly do."
He looked round at the three of them, all agape and very, very confused.
"I'm a time traveler," he said. "And I'm here to tell you why you can't go back in time and stop this great evil wizard whose name everyone fears to speak."
"Well, why can't we?" Ron asked, a bit belligerently. "It would stop a lot of bad things happening!"
The Doctor's smile faltered a little, and he nodded. "It would," he conceded, "Were it possible. You see, you exist in what we time travelers call a fixed timeline. Basically, what that means is that everything in your timeline cannot be changed. Everything that exists already exists. Going back in time doesn't actually change history, because history has already happened, with respect to your interference. Make sense?"
"Not really," Harry and Ron said in unison, but Hermione (of course) was nodding her understanding.
"He means," she said in a long suffering tone, "That if we had gone back in time and stopped You-Know-Who, he wouldn't exist now, because he would never have come to power in the first place."
Harry and Ron exchanged a glance, Ron's eyebrows on the verge of disappearing into his hairline and Harry's wrinkled as he tried to piece it all together.
"So," the Doctor said in his jovial tone, "You can't possibly go back and stop him, so just give your little Time Turner back to your Ministry and go on about your lives!"
Hermione nodded sagely, and Harry and Ron, while still attempting to figure it all out, decided to agree with her since she was usually right about such confusing matters.
"Thank you, Doctor," she said.
"Of course!" he replied with a grin. "And now I must be getting back to my own timeline! I've got an appointment with Queen Elizabeth the First!" And with a jaunty wave, he bounced back into his police box, which promptly disappeared into nothingness with more wheezing and groaning.
The trio exchanged a long look.
"You're sure we can't just-"
"Oh, Ronald."
