Merriam Webster Dictionary defines a dream as "an idea or vision that is created in your imagination and is not real". Of course, such definitions are bound to have traces of inaccuracy in this day and age, as at the point when this dictionary was written people didn't fully understand dreams, didn't understand how they were formed in the mind, etc. But this definition is quite possibly more obsolete than any of the others, because, as Sherlock found out that September of 2015, dreams were by no means unreal.
Sherlock's dreams were like everyone else's, seemingly nonsensical, but he was able to explain them. Most were lucid, as he was clever enough to recognize when he was in a dream. But while it may have been more difficult in a dream, Sherlock could tell when something was off in any situation. And the first dream he had about the Doctor was most definitely off.
It started fairly normally, as far as dreams go. He found he was in Baker Street, and everything was exactly the same, only his flat was replaced by a massive spider web. He was seated in a chair held up by the strands, trying to focus on a case about a murder, only spiders kept bothering him and gossipping about people he didn't know. He often dreamed about spiders and spider webs. It had been linked with feeling like an outsider or unusual, which was true and accepted for Sherlock. He knew it was a dream and the case was meaningless, but he couldn't help but focus on it anyway.
Then it changed. He found himself standing in a nice, furnished sort of room, like the waiting room at a therapist's office. It had two couches and a chair surrounding a brown table, a few pictures of flowers on the wall, a red carpet, and a classy, decorated light fixture. It wasn't exactly impressive, but he never remembered being here before.
"Jammy Dodger?" someone said. Sherlock looked around for the voice, in the corners and to the door, only to find when he looked back it was coming from the strange looking man on the velvet red couch. He had appeared only a few seconds ago, along with the tray of jammy dodgers on the table in front of him. The man sat casually against the arm and back of the couch, one leg crossed over the other, with an aloof sort of smile on his face. He had a tall, fairly skinny figure, gravity-indifferent brown hair, a sharp, protruding chin and greenish brownish eyes. He wore a white button down and a brown jacket, with a red bowtie and suspenders hidden underneath. Sherlock would have been more confused were this not a dream, but even still, he'd never seen anything like it. Not to mention it was far more vivid than usual.
"This… is a dream, right?" he verified.
"Oh, yes, of course!" The strange man agreed, raising his eyebrows and nodding, "I know, they won't taste like much, but your brain will get the signal that you're eating a jammy dodger and in the moment it'll feel like you can taste something," he said, peering at his jammy dodger, "That's something I suppose."
It would have been smarter to be untrusting, but he couldn't get hurt by doing something in what he knew was a dream. So he shrugged. "Alright," he said. Jammy Dodgers were pretty good. He grabbed one off the tray as he sat down on the opposite side of the couch. He took a bite into it. It didn't taste like anything, but his mind was trying to insist that it was sweet and he could imagine himself pretty far. Like reading a very descriptive story in the second person.
"I haven't seen you here before," Sherlock said, creasing his eyebrows as he crossed one leg over the other.
"Oh, well, that could be normal. It is a dream, can't always be sure what'll happen," he casually explained, taking another bite of his jammy dodger. Sherlock nodded. It was true, and yet he didn't quite believe it. He'd never had a dream like this before, and none of it fit with what was in his mind. Eating sweets in a dream indicating implications of a faith he didn't have, waiting in a room, meaning he was tired of waiting, but he had nothing to wait for. This really was odd.
"So, what are you trying to tell me?" Sherlock asked him.
"Tell you?" the man asked.
"Well, I assume this is some complex message from my subconscious," Sherlock responded coolly. The stranger laughed softly as though there had been some amusing misunderstanding.
"Oh no, you have me all wrong," he told him, "I'm just popping in to say hi, I don't live here," he explained vaguely. His eyes swept around the cheap little waiting room, noticing little details. Sherlock opened his mouth to speak, confused, but was cut off. "Quite a nice little place you've got here. Very complex,"
"What… my mind?" Sherlock asked with a cock of his head.
"Yes, precisely. You must be very clever, most people can't put in so much detail while they're asleep," his eyes locked onto the ground, "Even the lint in the carpet..." he said idly.
Sherlock ran this through his head. Why would he compliment him like this, as though he'd never been here before? If this was a message, he couldn't understand it. He backtracked to something he'd said before, the best place to branch a question off of.
"What did you mean you don't live here?" Sherlock asked, "Live where?"
"Your mind," The man said making brief eye contact before looking around the room again. Sherlock creased his eyebrows, trying to find some logic in what he said.
"But… you're in my dream," he stated obviously. He knew he must have looked quite stupid, but nothing had been this nonsensical in a long time.
"Yes," the man agreed.
"Therefore you must be part of my conscious mind or my unconscious mind."
"Mm, no," the stranger disagreed.
"What do you mean 'no'?" Sherlock snapped incredulously.
"No, I'm neither part of your conscious mind or your unconscious mind," his eyes drifted around the walls. Upon following them Sherlock found that the pictures were a different color than they were before, the red roses becoming yellow tulips. He did a double take. Not really unusual for a dream, but still startling.
"Then… who are you?" he asked, refocusing.
"I'm called the Doctor," he said, making eye contact with him once more.
"Alright, so…" Sherlock said, unable to keep a smile off his face. The man was just too interesting to wake up, "Supposing I decide to believe that you're not in my head, where are you?"
"I am in your head," The Doctor responded, "I'm just not from your head."
"So you just decided to come into my subconscious for a visit?" Sherlock asked, disbelieving.
"Yes. Well, no, I mean, sort of." The Doctor said, trying to get a hold of too many thoughts at once. "I mean, I love the visit, but actually, that's not the only reason I'm here."
Sherlock creased his eyebrows, leaning forward. "Why are you here?"
"We'll get to that in a second," he responded with a passing hand gesture. It turned the carpet beige, but Sherlock ignored it. "First, you're probably wondering how I'm here,"
"Yes," Sherlock agreed, "And besides that, where are you?"
"I told you, inside your head."
"No… I mean, your body. I know that I am asleep, reclined in my bed and when I awake, that is where I will return. Where are you that you can just pass into my head?" Sherlock explained. The Doctor gave an untrustworthy sort of smirk, tapping the foot of the leg crossed over the other on the air.
"Psychospace," he told him simply.
"Psychospace?" Sherlock asked.
"Ever heard of it?"
"Can't say I have,"
"Well, I need to get out of it."
"But what is it?"
"In due time, anyway, back to why!" The Doctor said, quickly changing topics again. He leaned forward. The Jammy dodgers vanished and the light fixture turned into a lamp on the table beside them.
"You're clever, Sherlock," he told him, "And I need a very clever mind to get me out of Psychospace!" Sherlock leaned forward too, beginning to get frustrated.
"You have to explain what that is first! And who are you, Doctor who?"
"Not important, not important!" The Doctor said, waving his hands around in a frazzled manner. The sofas turned blue. "Can you help me?"
"Help you what?"
"Escape!"
"Escape what?!"
"Escape the Psychospace!"
"What is Psychospace?!" Sherlock demanded furiously. He smashed his hand on the table and sat up rapidly in his bed. The Doctor was gone. He was awake.
"Dammit…" Sherlock whispered sharply, looking around at his empty bedroom. He knew at this point he wouldn't be able to get back to sleep. So, reluctantly, he got up and got dressed.