Disclaimer – I don't own any of the characters, nor do I profit from this writing. It's purely for my own and other's enjoyment.


A dark alley stretched impossibly long between two dark walls. Deep shadows were cast down over the uneven ground, setting a perfect stage for the sight laid in front of him. Perhaps it wouldn't have been quite so eerie if there hadn't been red covering nearly every surface down the length of the crumbling brick barriers.

The stench of blood was thicker here than it had been in the store. Copper filled every crevice, flooding his senses with unpleasant muck and clogging his brain so much that his vision tilted slightly. Never had he encountered something so foul, so malicious, so downright disturbing. Even within nine thousand years he'd never come across anything like this.

Gore was splattered haphazardly across the alley walls. It was almost impossible to tell what the blood had come from in the first place. Dark, black splatters accompanied the red, mixing in with the remains of some creature that had stumbled into a situation worse than he had ever seen.

It is important to understand that it takes a lot to bother the Doctor. There are very few things he has yet to see, and even less that could extract such a reaction. But this… The pure destruction and viciousness of this. The animalistic ravaging against another human – the Doctor could sense it was once human, though the stench of demonic residue very nearly covered it – was more than sickening, even for him. He felt as if he would topple over, overwhelmed by something so repugnant that pain seared his heart for the poor thing that had to go through this. Nothing he knew could commit such a crime. No creature he'd ever met of was capable of something so devastating.

It was as if a bomb had gone off inside a person, but without enough force to burn any parts of them away, leaving every last piece of their remains strewn through the street. For the first time in nearly seven hundred years, bile rose up the Doctor's throat.

"I am so… So sorry," he whispered hoarsely, wishing he had somehow gotten there sooner. How was he going to find what did this? Stop it from striking again? What was possibly capable of this? Every last creature he knew destroyed for their own survival, or simply to get rid of a species, but whatever had committed this looked as if it had done it for the sole purpose of stringing another living being along the walls.

The sudden roar of an engine distracted the Doctor momentarily. He instinctively melted into the shadow behind him, not having enough time to think through facing whoever had come in search of the same thing he had. A black car screeched to a halt in the entrance to the alley and two men got out. One was very tall, with long hair and an angular face. He immediately flinched upon seeing the alley, but didn't speak as he followed his companion to the back of their car. The other man was shorter but also with an angled face, creased deeper than it should have been at such a young age. The Doctor immediately got the impression that these two were not simple humans. Their eyes were deeper than they should have been, darkened by what could only be a difficult past.

For a moment the Doctor felt a flash of sadness in his chest, but then the surprise caught up to him and a million questions flitted through his mind. Who were they? Why were they here? And most importantly, what were those guns for?

They had both come back around the car, armed from daggers in their boots to hidden knives in their jackets. They watched the alleyway cautiously, but without fear. Rather they looked sad and resolute, as if they had seen this before - which of course only increased the Doctor's curiosity and sympathy for the two men. He considered, for a moment, revealing himself, but another screech averted his attention.

Two more men ran almost immediately into the alley, pausing once they caught sight of the first two. One was tall with careful features: sharp cheekbones, narrowed eyes and deep brown hair. The other was shorter with a stricter face but not so heavy of a heart or expression. Not like the first who, immediately, struck the Doctor as someone with great intelligence.

The two men already in the alley both trained their guns on the others without hesitation. The shorter of the two murmured something close to, "Son-of-a-bitch," and the taller one grit his teeth slightly.

"John," the intelligent man spoke calmly, watching the two across from him with deft precision. "Please do not continue removing your gun. These men will shoot us if they think we are a threat."

"Who the hell are you?" the tall man with the gun asked, ignoring the bold statement from the darker figure across from him.

"Sherlock Holmes. Consulting detective. And you are…" he trailed off for a second, cocking his head slightly. "I have seven ideas. No, six. Five if that is a knife… Oh yes. Five."

The serious man that Sherlock had called John let out a slight groan. While he looked exasperated, the Doctor could see he wasn't actually scared. Rather, he looked quite comfortable next to his tall companion, even when faced with a life or death situation. Though, if the Doctor truly believed it would escalate to that he would of course interfere before anyone was hurt.

"Excuse me?" the shorter of the two men with the guns asked, his grip on the weapon never relaxing, though his arm lowered slightly.

"Three. You are very odd people, aren't you? But not the murderers. You didn't cause this," Sherlock's voice remained neutral as he glanced around the alley. It was almost as if he was scanning the walls for information. He continued, "Which is curious, considering you aren't surprised to see this mess. And you aren't surprised to see me either, so you already knew who I was… Explaining why the tall one lowered his gun so quickly."

The Doctor raised his eyebrows, glancing over to see that the one man had indeed lowered his gun. He cocked his head slightly, both shocked and impressed with the man's observation skills.

"I told you he was good, Dean," was the tall man's only response, though he looked impressed.

The shorter man, Dean, finally lowered his gun. His eyebrows were furrowed in a sort of angry confusion as he carefully watched Sherlock, who looked mildly bored with both of them.

"Well then tell us your name, so we can move on with this," Sherlock finally sighed, glancing at the tall man again.

"Sam."

"Lovely. Now, have you two figured it out yet, or shall I walk you through it?" the man asked, loosening a pale blue scarf wrung around his neck. John glanced at him again, the permanent respect for his companion shining through on his face.

The Doctor was more than a little surprised with this bunch. What were the chances he would stumble upon a meeting like this? He supposed it only made sense, considering the atrocious state of the alley way. Though he still wasn't sure whether he was intrigued or wary of all these people. Such different talents… Oh, humans were clever sometimes.

Apparently neither Sam nor Dean had offered any answer to Sherlock because the man straightened and, with a sort of sneer in their direction, turned to examine the alley more thoroughly.

"The blood is spread further than a simple explosion would cause, even assuming that the bomb left no traces, which it has not. So the most obvious explanation is ruled out. It also could not have possibly been a man, because the blood is splattered, and no human has the skill, patience or precision to cause such an effect on the bricks, not even someone like me," Sherlock paused for a moment, bending down to stare at a dark spot on the ground. "There is also another sort of substance left over, but it is not from a human, nor any other oil I'm familiar with. Smells like… Sulfur and copper."

"We could have figured all that out on our own, thanks," Dean cut across suddenly, glaring Sherlock without patience. "Unless you have anything useful, it would be nice if you could get the hell out of our way."

Sherlock stood slowly, an icy flash flickering through his eyes as he stared over at Dean in annoyance. "You're ruining my fun. And I figured it out at least eighteen times quicker than you would have, so you should be thanking me for saving you both time."

Dean opened his mouth half in disbelief, looking ready to yell some more when Sherlock simply let out a sigh and gestured to the side of the alley.

"As I am quite sure your unobservant brain did not notice, there is a scuff mark on the ground, smudging a bit of black muck slightly to the left and leaving a line behind. Another lighter mark is located a man's foot length away. If I am not mistaken – and really, it is a rare occasion when I am – someone has been listening to this entire conversation. Isn't that right?"

The Doctor suddenly found himself staring into deep, calculating eyes, and he realized that Sherlock had known he was there the whole time. He felt his mouth twitch up into a slight grin, pleasantly surprised at the amazing human he had somehow found.

Though of course, the other three men hadn't been expecting that. John, who had otherwise been quiet, let out a muffled sound of surprise and drew a gun. The two other men had their weapons pointed at him just as quickly. The Doctor's smile quickly diminished and he narrowed his eyes, disapproving of the situation. He still wasn't completely sure how to feel about these men, and yet they were so brilliant, so different than all the other people…

With a slight sigh he stepped out of the shadow and into the light shining from the entrance of the alley. Clearly he wasn't what the others were expecting, not surprising him too much. Sherlock, he knew, was still staring intently at him, presumably looking for clues about his life.

"And who-?" Dean started, but the Doctor raised a hand to silence him, smiling again.

"I am the Doctor. And I would greatly appreciate it if you lowered your guns because, as you see, I am unarmed and could not get past four of you anyways."

Sam stared at him, frowning, as if he couldn't figure something out. Sherlock also looked slightly surprised, for the first time seeming genuinely puzzled. The Doctor met his gaze for a second, struck once again by an intelligence nearly equal to his own.

"He is unarmed…" Sherlock trailed off, still examining him. John lowered his gun immediately and, after another few seconds or so, the other two did as well.

"I would believe you have questions for me," the Doctor said quietly, looking back to Sherlock. The man's lip twitched, as if he were pleased about something, but then went back to the same calculating expression. To the Doctor's surprise, it was Sam that spoke first.

"You… Have two heartbeats. What are you?"

The Doctor raised his eyebrows. That was definitely a first. No-one else had noticed the two thumps of his alternating hearts. Then again, he wasn't usually this daunted by others. Perhaps it was wariness he felt in the situation. Not fear, but rather adrenaline, mixing with both his excitement and wonder. It must also mean this human was a hunter of some sort, careful to look unusual things such as that.

This time Sherlock's mouth did flick up into a smile. "You aren't as useless as your brother," he stated, causing Dean to scowl.

"What is that supposed to mean? And how did you know we are-?"

"Please stop talking. I am curious to know how this man does have two heartbeats."

The Doctor grinned, standing slightly straighter. "Well I have come across quite an interesting group, and I suppose there is no point in hiding… I am a Time Lord. The only Time Lord left."

"You're a monster?" Dean asked in surprise, raising his gun quickly again, with his brother following suit a little slower.

"Don't be ridiculous, monsters aren't real. And he did not do this, either," Sherlock said immediately, walking towards the Doctor briskly until they were standing only a few inches away from each other. He was met once again by the intense gaze, and this time they stared at each other for a long while, gaining insight on the other. The intelligence the Doctor had measured before seemed impossibly intensified. Even more understanding, more wit and brain was present than he had originally thought. It was shocking again, seeing someone with such a clever light to their eyes, more than any one of his companions had ever been before. He couldn't quite decide what it was that sparked such a strange feeling for the person in front of him, but it was there nevertheless.

"So old…" Sherlock murmured in surprise, throwing the Doctor off. He hadn't been concentrating much on the rest of the man's expression, but now his eyes moved to take in his face he was surprised. Sherlock looked confused and wary, and maybe even a little scared. The Doctor got a solid impression that this man very rarely got scared, and it was only something unknown like him that could have induced that reaction.

"You've seen so much. So, so much," Sherlock continued, eyes widening slowly. "You… Are you a monster?" the words came out quiet and slightly rough, as if Sherlock had never had to ask a question like that. The Doctor suspected he never had.

"I am not a monster," the Doctor said calmly, not breaking eye contact. He hated being a figure of fear for the very things he tried so often to save. "And I am also not from this planet. But I don't have my own planet any more. All of my people are dead. So I am left with the job of cleaning up the messes of the universe."

Sherlock blinked slowly, his eyes flickering. The Doctor could practically feel the other man's mind whirring, half of his brain telling him it was impossible, and the other half telling him that he was being truthful.

"Can I show you something? I believe it will make it easier to understand," the Doctor muttered, his face serious. There were few times he considered doing this, but for someone like Sherlock he felt as if the only way to convey himself was through such a message.

Sherlock opened his mouth for a second, slightly torn, before he nodded his head lightly.

"This will feel invasive. But if you do not want me to see something, you can just picture a door."

The Doctor gave Sherlock very little time to prepare before he grasped either side of the other man's head lightly with his hands and opened the connection between their thoughts. He let his experiences flash through the other man's mind, from the beginning of his childhood on his own planet to finding the TARDIS, to having to destroy his own planet, to all the companions and the emotions it wrung. At the same time his own mind was bombarded by Sherlock's own experiences. A rough childhood, never understood by his parents, a desperate feeling of being unwanted and lonely, few people he could trust, and even fewer that could understand. He had no friends for a long time, none save John, who finally showed up and changed everything-

Sherlock violently pulled away, gasping for air. His eyes were wide in a mixture of pain, disbelief, and brief understanding before they rolled back in his head and his legs collapsed beneath him. The Doctor darted forwards quickly to catch the man, staring down at him in surprise. He felt drained, more drained than he ever had when sharing a mind space, and suddenly everything was in a sharper focus.

"Sherlock!" John ran forwards quickly, eyes wide in fear. The man's hands were steady, however, when they deftly checked for a pulse.

"I haven't hurt him, John," the Doctor said sincerely, gently laying the man on the ground, avoiding any spots of blood. "The connection between our minds was just… More intense than they usually are. I believe his mind was overwhelmed by the amount of detail he was able to take in."

John stared at him in a mixture of horror and confusion, not completely sure what to think. Eventually he simply nodded and went back to his serious mode, pulling off his jacket to use as a pillow for his companion. The Doctor stood slowly, glancing back to the two brothers to see what they thought of the exchange.

Both Sam and Dean were talking in hushed whispers, glancing over at him on occasion with hardened eyes. He realized then that they were familiar with 'monsters' – that they were trying to put a name on what monster he was.

The Doctor slowly walked towards them, noticing the immediate tensing in both the brother's backs.

"Can I just explain what I am?" he asked. Dean stepped forward in response, looking almost disgusted, of all things. It was a bit offensive, really.

"What, like how you explained to him?" he gestured to Sherlock, eyebrows pulled down over his eyes.

"You don't understand. I know you two believe I am one of the monsters you hunt, but-," the Doctor reached out to put a hand on Dean's shoulder and several things happened at once. First a man appeared – literally appeared in front of him, with no use of a teleportation device – and then that man, who the Doctor realized quite quickly wasn't actually a man, shoved him away from Dean with enough force to knock down a building.

A sharp pain laced through the Doctor's skull as he was thrown against an alley wall, and he suspected one of his shoulders popped from its socket, but he was too busy being surprised to think much of it.

The man appeared in front of him again and laid a hand on his forehead. The Doctor's eyes flickered shut as he felt the man – or, rather, the being, because he was certain this man wasn't a human – briefly invade his mind.

"You're an angel?" the Doctor asked in wonder, his eyes suddenly snapping open as the being stood up again. "A real angel?"

"You are not from this planet, but you watch over it," the angel responded in a rough voice, mostly confused. He sounded slightly tired as well. "I am sorry for throwing you. I believed you were trying to hurt the Winchesters. Here," the angel placed his fingers on the Doctor's head again and a curious sensation traveled through his body, mending the scrapes on him. It was similar to when he regenerated and mended himself, though this was a very different, peculiar power source.

"A real angel… I had an encounter with a demon once. But never an angel."

"My name is Castiel," he said, turning slightly to look back at the two brothers. Dean was staring at Castiel in a mix of strong emotions, throwing the Doctor slightly off guard. Clearly they had a strong relationship.

"I am the Doctor. And I believe you will need to explain to your companions who I am, because they believe I am some sort of monster."

"They do not know about your kinds of monsters, Doctor," Castiel said solemnly. "They only know about the kind that ravages against people like the thing that tore up the human strewn across this alley."

"Do you know what it is?" the Doctor asked seriously, his voice lowering. He had nearly forgotten about the first reason he'd come here.

"No. But I have an idea. And it isn't something me or you has ever come across."

"I had a feeling I found these remarkable humans for a reason," the Doctor smiled slightly. "It's going to take all of us to bring it down, isn't it? I love a good mystery!"

Castiel blinked slowly, his face still grim. "I fear it will take all we can offer. Maybe more."

There was a brief pause in which two of the oldest beings on the Earth exchanged worried looks. Then the Doctor straitened his bowtie and smiled again.

"Well then, we should get started, shouldn't we?"


Author's Note: All right, so, a few people have asked me to keep writing this. I originally planned on just having it leave off so your own ideas could be formed on the impossible creature, but if more of you would like me to continue it, I might add more? I will probably finish the other fanfics I am writing first, though. Anyways, if you would like me to write a sequel, let me know. If a lot of people are interested I will definitely try to add a few more chapters!

Edit: Ok I will definitely continue this! I promise! I just have a lot of fics going on, and a lot of homework, plus a bunch of extra work for a musical I'm going to be in, so I'm not sure when I'll get around to finishing it. I'll start writing ASAP though ok!