AN: I own nothing. This is a BBC's Sherlock/Harry Potter crossover. There will be slash in later chapters. Also, sensitive and graphic topics, in later chapters. Since it doesn't have a name, I christen Harry/Sherlock slash "Sherry."This story is AU from halfway through the 7th HP book. It takes place after His Last Vow, in the Sherlock universe.

Please review. It would make me oh so happy, and give me the needed motivation to write more and more. Not that I'm begging, or anything. But please do :)

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"The world is full of obvious things which nobody by any chance ever observes."

-Sir Arthur Conan Doyle, The Hound of the Baskervilles

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Important Things (You've Forgotten)

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Sherlock Holmes was not an easy man to fool.

Moriarty, being an exceptionally clever bastard, had gotten the closest. Nonetheless, Sherlock was always a step ahead. Magnussen, in a way, did fool him; but it was quickly negated by an unimpeded bullet straight to the skull. Sherlock had gotten the last laugh with that wormy, rude man. The most dangerous and devious criminals had been outsmarted time and time again by Sherlock Holmes.

Sherlock Holmes is not comfortable being outsmarted.

However, when two innocent and perfectly normal residential buildings were not only outsmarting Sherlock, but in fact fooling him, Sherlock Holmes lost his temper.

"It HAS to be here, Watson!" He was pacing back and forth on the sidewalk in front of the two brick town houses. His frustration seemed to be growing every minute, which was saying something, considering Sherlock had been at it for almost 2 hours. Evening was drawing on, and it was getting progressively darker.

John, who was usually more than confident in his best friend's mental competency, was beginning to have some doubts. It was not at all helped by the looks strangers gave them as they passed the odd pacing man on the street, and John, who had been trying to look as casual as possible.

"Sherlock, I really don't understand." John said to his friend, now worry showing in his face. Perhaps Moriarty, seemingly returning from the grave, had affected the genius detective's perception of reality. John was worried, as a friend, a colleague, and mostly, as a doctor.

"Listen," Watson went on speaking, hoping he might calm his friend,

"Listen Sherlock, there's nothing here. There's number 120, yes. Over here is number 124. There is nothing in between them. 122 Archer Street simply does not exist. It's a fluke, and error in numbering. I really, really, do not understand what we're doing here."

"Well, that's hardly new is it! You, not understanding something. I believe you've been told to put that on a shirt, and now it seems quite appropriate that you do. Now, stay there, and just let me think!" Sherlock was in full temper tantrum mode, that much was obvious.

'Nothing for it but to let him ride it out.' John thought. John had thought this whole case rather weird. Not in the usual way, and not in a clever way, like most of their famous cases. This one was...unsettling. It had felt like that from the beginning, from the little house in Surrey. John Watson had an anxious feeling, like they were digging too deep, meddling with things they ought not meddle in. The feeling intensified ten fold when they came across this street, and the two houses with a missed number in between them. John believed Sherlock felt it as well, an instinct, coming from the pit of his stomach, to leave this place, and the riddle of the missing number.

Sherlock was now staring at the gap between the two houses. His gaze was intense, the anger clearly showing on his face. John thought perhaps this was an improvement from the pacing. Although, now he was murmuring to himself, which considering Sherlock, was not altogether strange.

"It must be here, can't be underground, soil is all wrong, shade from trees indicates house was build in the 40's, neighbors are new, old ones had seen it, gap too small, bigger on the map, more than one map, eliminate the impossible..."

A cat was lazily ambling up the street towards them. Probably a stray, John thought, no collar. It did have a mangy look about it, the fur was white, but there were gray splotches of dirt on its coat. It passed right by Watson, and pausing at Sherlock's ankles, gave a resounding meow.

John saw Sherlock jump, and quickly look down to locate the source of the disturbance.

"GO AWAY!" Yelled Sherlock, unjustly taking out his ire on the cat.

Two things happened in such a quick succession that even Sherlock almost missed it. The cat, frightened, bolted through the gap between numbers 120 and 124. For a second, Sherlock thought he saw the cat flicker, as though the white animal was a mirage. His sharp eyes, ever observant, made sure to follow the little beast. The cat stopped not far away, but now it was sitting on the porch of a house, which had inexplicably (and finally) appeared. It had peeling white paint and an unkempt lawn. The number above the door was 122.

John gaped. There was no way that house was there a split second ago. He looked to the two houses on either side, to confirm that there was no way there was room between them for another. But, as though it was all a matter of course, the two houses had become thinner, and further apart. 'This,' John thought, 'was the most abnormal thing in the world.'

Sherlock on the other hand seemed ecstatic.

"Yes! What did I tell you John? Oh this is brilliant, some sort of mirage, or illusion, (possible mirrors) and I'm not sure on the exact method, but we will find out I'm sure... Get your gun out, remember this Potter character is supposed to be dangerous. Come along!" Sherlock was already striding up to the door, on the walkway, that was literally not there a second ago. John was still gaping. His brain was firmly telling him that what he was seeing was completely impossible, no matter how many mirrors one uses. However, quick soldiers reflexes had him following orders, with his gun at the ready, he ran behind Sherlock, stopping at the door of the impossible house.

"Alright, I'm going to pick the lock. There's a chance we've been spotted already, but if we haven't, I want to try to take him by surprise." Sherlock said under his breath, and rummaged his pockets, looking for something to pick the lock. John's heart was racing. The anxiety he had felt was increasing the more he stared at the house. The house looked to be in need of upkeep. Some of the siding had peeled off, and the windows had a layer of dirt. Looking up, John noticed one window lit by interior light. There were curtains, and a flower on the windowsill. He noticed the flower was a purple Orchid, which were Mary's favorite.

Mary.

Something so important, he had forgotten, he had to go as soon as possible.

"Oh god, Sherlock, I have to leave now. It's our anniversary. Oh my god, I can't believe I've forgotten, Sherlock she's going to kill me!" John stammered out, and started running back down the walkway toward Archer Street. This whole stupid case had him on his feet, running behind Sherlock for the last two days. He can't believe it. His mobile was still sitting at Baker Street. Mary's probably called dozens of times now.

"Wait, John!" Sherlock was right behind him, grabbing his arm.

"The gun, give me the gun. He's supposed to be dangerous. I'm going to need protection." John practically shoved his gun into Sherlock's hands. Being a good soldier, he knew you should always treat a loaded weapon with respect, but at the moment John has lost the ability to think clearly. His mind was a jumbled mess. John kept having the same thought over and over, stuck in a loop: 'She's going to kill me, literally, she's capable, and she'll do it. I have to get out of here. I have to get home.'

Minutes later, the doctor was hailing a cab on Main Archer, panting from sprinting from the doorway of the impossible house between 120 and 124. He would be halfway home, sitting in the backseat of his cab, before his mind finally cleared, and he was able to think rationally. He was already home, running up the stairs before his mind had a chance to doubt. Seeing Mary upstairs, sitting at the table reading a journal, it finally hit him. Their anniversary was a week from now.