Author's note: Okay, this is my first venture into the Sherlock fandom, and my fourth into Harry Potter, and my second into crossovers, so I hope I got it right.
I just wrote this because I was saddened that there wasn't more of this plot. It's all about their time at Hogwarts, not what might have happened after, and I find what happened after much more interesting.
Disclaimer: I do not own Sherlock or Harry Potter.
Sherlock was, by no means, normal. Not in any way, in any sense of the word, or in any aspect. No, Sherlock was perfectly odd, thank you very much, and would prefer to stay that way, if John was what was considered normal.
Especially the 'Muggle' part about John. That was something that really put him off.
You see, the reason Sherlock's apartment was so dirty was because he was used to using Scourgify on any and all surfaces that were a bit less than clean, and used to putting things in impossibly large cupboards that were bigger on the inside. That was why he was so hard to get a flatmate for, and he didn't expect his Muggle friend to go out and get him one. He was a wizard, and normal people weren't supposed to live with wizards.
Unfortunately, there John was, and there went all of his magical artifacts.
Yes, John was perfectly normal, and that is why Sherlock was currently gaping like a fool, standing in the middle of Diagon Alley and staring at... John.
John was currently gaping like a fool as well, and as soon as he shook himself out of it, the first thing that came out of his mouth was, "Well, I guess I should have known."
Sherlock simply nodded, still too shocked to speak. Then the anger at being wrong filled him, and he cursed as he looked John over and noticed all the signs of a wizard.
John's back pocket was worn, as if he had pulled out and replaced something in there several times a day. Of course, it could have been his phone, but the signs clearly showed that it was a wand- a white, thin line of wear and tear that no phone could make. Presently, there was a wand sticking out of it, and Sherlock told himself to tell John about how illogical it was to keep your wand in your back pocket later.
Then there was the fact that when John hurt his leg, it was right after the second Wizarding War, and wasn't physical, so it had to be psychosomatic, didn't it? Wizards had little experience in curing the mind, which also explained the therapist.
Also, the fact that he looked around constantly, as if hunted- as though Death Eaters or Snatchers could be just around the corner. If he were a muggleborn, and suffering from mental problems, as he did, it would make perfect sense to be afraid.
Not to mention his dislike of cleaning, his adversity to the normal, his lust for danger, his-
"Done having a revelation yet?" said John, and Sherlock was pulled back to the present.
"Shut up," said Sherlock as he headed to Gringotts, finally remembering what he was there for.
"What, that's it?" asked John, following him with an indignant huff. "I'm surprised a genius like you didn't notice the signs earlier, you know-"
"Shut UP!"
Needless to say, 221B Baker Street was much cleaner from then on.