Disclaimer: Harry Potter is owned by JK Rowling. All associated rights belong to Bloomsbury Books and Warner Bros Motion Pictures. Doctor Who and the TARDIS are trademarks of the BBC.

Author's Note: This is a companion piece for the end of Chapter 4 of my story "Harry Potter and the Second Chance". I'm writing this because I'm so eager for the new episode of Doctor Who on Christmas Day, my brain's churning out scenarios left and right.

The TARDIS materialised with a thump, throwing the Doctor to his knees on the metal grating, before he pulled himself together.

"Okay... so, this is where that disturbance is coming from." He mused out loud. His mind was still a little shook from his recent regeneration, causing him to verbalise most of his thoughts, to give him the time he needed to work it through.

He strode to the door, opening it and stepping out.

Harry Potter, young wizard, was unpacking his new television from it's packaging. He'd still need to charm the device to work off magic instead of electricity, but the journal his mother had left in the Potter Family Vault contained details about the charm he'd need.

A wheezing/groaning sound filled the air. Before he could even think it, Harry's wand was in his hand, pointing to the corner of the room, where a large blue box was starting to appear. Harry moved slightly, making sure he was in a good spot to blind-side whatever the box's occupant was.

When the door opened, a man stepped out, clad in a ridiculous outfit, even for the Wizarding world. Harry lowered his wand slightly, seeing the confusion on the man's face.

Unfortunately for Harry, his first words were not complimentary. "Well, you're not human." He said, looking the invader over.

"Who are you?" The man asked, his voice indicating that he came from the Manchester area.

"I asked first." Harry said, not lowering his wand.

"Well, I'm the Doctor." The man said, looking around the room.

"Well, Doctor." Harry looked the man up and down for a moment, not seeing a weapon or wand on the newcomer. "My name is Harry Potter. May I ask what brings you here?"

The Doctor stared at Harry for a moment, apparently seeing what he was looking for. "My scanners detected a temporal anomaly here. I came to fix it."

Harry arched an eyebrow. "You're some sort of... temporal handy-man? Fixing the problems in Time?" He asked.

The Doctor shook his head. "No. I'm a Time Lord." He looked infinitely sad for a moment. "I'm the last of the Time Lords. We monitor time and space. Whenever we detect someone messing around with time, we fix it."

Harry shrugged. "Well, I suppose that I'm the anomaly that you detected. I destroyed the time-stream I came from when I came here. I was using a revolutionary piece of technology that no longer exists."

The Doctor shook his head. "There are ways to take you back."

Harry shook his head. "Not according to the research the project did. The cardinal rule was to never step into the time that you were visiting, since it would change the past. Once I got here, I ended up destroying that future."

The Doctor looked very sad. "Why would you do that?"

"I lost everything that mattered to me, Doctor." Harry replied. "As such, when I came back, the me from this time was destroyed, and I absorbed his DNA, in essence regenerating my body into its current form. If I was to be removed from this time-stream, there would be no Harry Potter here."

The Doctor slumped onto one of the couches. "I've been where you are, Harry." He said. Harry looked into his eyes, and saw the same haunted look that he saw in the mirror every day.

"Who did you lose?" Harry asked gently.

"Everyone." The Doctor replied simply. "My entire world has gone. Destroyed, not only from it's place in the universe, but from time itself."

"Sole Survivors." Harry looked at him. "What happened?"

"There was a war." The Doctor said, an infinite weight pressed on his shoulders. "A Time War." He laughed mirthlessly. "The Last Great Time War."

Harry nodded in understanding. "I assume that you won?"

"Won?" The Doctor gave another death's-head smile. "Well, I'm all that's left. Two mighty civilisations burned across space and time. Quite a fireworks show."

"You did something." Harry peered at the man, penetrating the aura of sadness, before a look of realisation filled his eyes. "It was you, wasn't it? You pulled the trigger."

The Doctor nodded. "We were losing. Our enemy was taking over everything. There was a way to stop them. And all it cost was everything I love."

Harry just nodded. "I've been there. Obviously, not on the same scale as yourself, Doctor, but I've been in that situation. We have no choice..." He shook his head, before settling his gaze back on the Doctor, noticing the clothes. "You know... that outfit really is not you."

The Doctor looked at his clothes. "What's wrong with it?" He asked, looking back at Harry with a confused look.

Harry grabbed his jacket. "Come on."

When the two men arrived back at Harry's flat, it was a very different looking Doctor. Gone was the Victorian frock coat, waistcoat and pants. He was now clad in black jeans, with a maroon long-sleeved T-shirt, and a battered leather jacket, that Harry had found in a Charity shop, not far from the Leaky Cauldron.

"So, Doctor. What are you going to do with me?" Harry asked, after getting the man a large glass of FireWhiskey.

"Dunno." The Doctor replied, drinking a long slug from his FireWhiskey. "You're doing the wrong thing for the right reason. Can't really fault you for that. Plus, I'd have to rewrite the whole universe to send you back."

"I'd prefer it if you didn't do that." Harry said dryly. "I didn't like where I came from. That's why I decided to come back. Make a difference."

The Doctor nodded. "I know the feeling." He stood up, polishing off his whiskey. "Well, make sure you don't mess about with time again. She get's temperamental if you play around with her too much."

Harry nodded. "Doctor... can I give you some advice?" The Doctor nodded. "Find someone, Doctor. I've spent the majority of my life on my own, after I lost everyone. It nearly destroyed me."

The Doctor nodded again. He headed back to the box.

"And a question... if you're an alien, how come you sound like you're from the North?" Harry asked.

"Lot of planets have a north!" The Doctor snapped back.

"Oh, Doctor? Just one more thing." Harry looked a little unsure. "When I was scanning the time continuum, just before I came back, I noticed some odd readings coming from 2005. Some kind of non-conventional technology. Since you're the Lord of Time, it might be worth taking a look at."

The Doctor placed his key into the box, opening the door. "You could... you could come with me for a bit. This box can go anywhere in the universe."

Harry chuckled. "Thank you, Doctor... but I've done the travelling I need to do. What I want... what I need is here, in this time." He marched over, extending a hand. "Take care of yourself, Doctor. Remember... do not be on your own. That way lies madness."

The Doctor entered the box, closing the door behind him.

He marched over to the console, relishing the feel of his new leather jacket on his shoulders. He set the co-ordinates; London, 2005. Maybe he'd find somebody to travel with there...