A/N: Hi everyone! Poli Bear here with something new... A Doctor Who One Shot! :) It was an idea that came to me while I was writing the series that I found so intruiging that I had to write it down! :D So I hope you enjoy it and don't forget to favourite either this or me, or if you don't feel like doing that just drop me a review :) I'd love to hear what you think of it:D

A Friend Lost

The Doctor collapsed onto his bed, weary and tired. Well that's what you'd feel like if you'd just had to outrun the collective hoardes Genghis Khan for the second time.

"Why?" The Doctor muttered to himself, "Why can't I learn to stay away from Mongolia around the 12th century? I already know we don't really get along." The Doctor sat up for a moment, stretching at the edge of his bed. "Still, at least he hadn't met me before," he grinned, remembering how he'd already travelled there and had met the Khagan for what would be the second time from his perspective.

The room that surrounded him as he sat there wasn't very remarkable, contrary to popular belief. There were a few well placed pictures on the walls of people who were very dear to him, a couple of dressers and a bed. That was it. Well, there was the colossal mess that lay strewn across the floor from bits of old screwdriver to scrap metals from strange planets; there wasn't a bit of the floor that didn't have some kind of failed contraption or "work-in-progress" occupying it. But apart from that it was relatively normal.

But there was something on his mind, someone who refused to die away. It seemed like, recently, they were always there, always waiting for him to acknowledge their existance in the deep well that was The Doctor's memory. And it was now, now that The Doctor was attempting to relax, something that he didn't normally do, that those memories started to float to the surface and indulge themselves.

The Doctor's eyes slowly flickered open, but the scene around him wasn't as familiar as he'd thought. The walls around him weren't really walls any more, they were cragged and rough to the touch, wet with eons of damp. The floor beneath his feet was cold and hard, that's when he realized he wasn't wearing shoes. "Ah!" He leapt of the ground onto a nearby rock but that wasn't much warmer. He started to shiver.

Then, as his eyes began to adjust to the dark, he could make out a small boy sat not too far away from him, his arms holding his knees tightly to his chest. Pyjama's clung damply to his skin and he looked really dirty. He was shivering too. "Hey there," The Doctor said, slowly walking over to the boy. The boy jumped, turning to look at The Doctor in shock.

"Who are you!" He shouted, panic-striken as he leapt to his feet. "How did you get in here?"

"It's alright," The Doctor said, his voice calm. "I'm not going to hurt you. I'm a good guy, and we all like good guys don't we?" The boy nodded. "Good," The Doctor said, taking off his jacket and handing it to the small boy. "Now, how did we get in here?" He muttered, hoping the boy would know the answer.

"I don't know," he whispered back. "I was with my friend, but we got seperated."

"Shall we find him then?"

"Yeah. Okay."

As they walked the cave gradually grew darker and then a light began to shine far away, like a firefly was dangling right infront of them. The boy suddenly raced off towards it and The Doctor shouted "Hey! Wait!" before chasing after him.

He soon burst out into a brightly lit room, to find two young boys in there, one standing at what looked like some kind of altar, the other shrunk back against the cave wall, paralyzed with fear.

"What are you doing!" The one against the wall shouted, staring at the other boys back with horror. "You don't have any idea what these things are, let alone what they could do to us!"

The boy at the altar turned around, his eyes burning with excitement. "But didn't you hear him?" He asked, and The Doctor recognized him as the boy he'd met earlier, even though the jacket he'd given him was no longer on his shoulders. "We could go anywhere we wanted, do what ever we desired, live forever! What more could you ask for!"

The other boy looked horrified at what his friend was suggesting, and then something seemed to register within his head. "No you can't! These must be the Eternals we've been told about, the ones that went bad! You mustn't listen to them!"

But it looked too late, the boy at the altar seemed too greedy, to enticed by the idea of adventure to listen to his friend anymore. He stepped forwards, and immediately a dark fog seemed to leap out and engulf him. The other boy rushed forwards, wreastling with the fog, attempting to save his friend.

Then that friend turned around, the fog following his movement and wrenched the boy away from him. "Leave. Me. Alone!" The young boy was thrown across the hall, where he crashed into the wall and fell, unmoving, to the ground.

The boy at the altar froze, the fog releasing him as he realised what he'd done. The Doctor stepped backwards in shock as he heard the voice that spoke into the boy's head in echo within his own.

What are you doing! Is this not what you desired most boy?

He wasn't listening, he just ran over to the crumpled figure and held him in his arms. He started to cry.

"What... have I done!" He yelled through vicious sobs. He gently rocked backwards and forwards, tears still streaming as he looked back at the altar. "Isn't there anything you can do! Why can't you help him?"

There was a ringing silence for a moment, and for a second The Doctor thought the voice had deserted him, but then it spoke again, pounding within his head.

I can save him yes. But is that really what you want? He will forget this ever happened but the pair of you will be cursed to rage against the other until the end of time itself, neither stopping, neither yielding.

"I don't care," the boy sobbed. "Just please... save him."

The Doctor sat bolt upright, his face covered with a cold sweat as he began to realize the room as his own. Back in the TARDIS. Safe.

But deep down The Doctor knew better than that. He knew that that boy would start the fight again, because the voice had been right. His friend had been saved, but the two of them had clashed like no others had and next time, he knew that it would be his toughest fight yet.