I'd like to thank Tumblr for the marvelous idea. All I have to say is "Headcanon accepted!". Oh, and enjoy! ^_^

Cautiously he turned the key in lock. He twisted the doorknob slowly so that it wouldn't trigger any noise. Once he entered, he walked directly, but quietly, to his brother's bedroom. There he was sleeping without even knowing that Sherlock was walking around the house.

He smirked upon the thought of how easily he could strangle him; he did say at John's wedding that it'd be utterly easy to do so. Oh, the so many times Mycroft had annoyed him, and the so many different scenarios he had pictured in his mind that resulted in perfect homicidal opportunities. Still he shook his head. He had annoyed him once again, and now he was going to set of scores like the very grown up man he was. Over the bedside table were a book and his reading glasses placed on top of it. His phone was there too, with the screen facing down. And so he started his very mature and evil-ish revenge plan.

He turned over the phone and moved the book and the glasses to opposite edge of the bedside table. Then he glanced the bedroom; there it was the door to his walk-in-wardrobe. There Mycroft kept all his suits, shirts, ties and shoes, perfectly lined and categorized according to colour and usage. Sherlock had a tingling feeling inside, excited like a small infant, not even knowing where to start messing with his brother's very organized wardrobe.

He quickly found enough ideas to make Mycroft go crazy as he disorganized no more than five suits, four pair of shoes, three ties and two shirts. Yes, he perfectly calculated that way so he'd leave his brother wondering what had he done with the one belt. Satisfied with his sadistic deed he moved to the living room. He couldn't do much without creating much noise so he was very thorough with what he was going to do.

Of course-just moving all the furniture slightly out of alignment would be spot on. Moving the table, the chairs, the couch. He did the same in the kitchen, leaving cabinets' doors open and changing places of products and packages. Though, when he got to his office room, Sherlock felt tempted in overstepping the mark. He took some books of the bookshelf and scattered them all over the floor. Everything that was over Mycroft's desk was changed place too; what was on the right was moved to the left and vice-versa. Ultimately he couldn't resist in dragging the chair to the outside of the room. He ended up leaving it by the closed door of the office room.

Mycroft had not even put his feet on the floor and could sense that something was wrong with his house. Every morning he stretches his hand to grab his phone. Today was no different, except for the fact that his still sleepy eyes gazed the back of the phone. He opened his eyes and noticed that the book was at the end of the bedside table. He kicked his sleepiness away as he kicked back the bed sheets. Looking up at the rest of the room, something struck him immediately. The walk-in-closet. The door was slightly open and he could see a red shirt. The red shirt is not kept there.

He walked to check on his clothing noticing immediately which were out of place. Five suits, four pair of shoes, three ties, two shirts and one… It had to be one thing out of place, it was the rational thought. He double-checked his clothing arrangement and realized nothing else had been moved. Making his way to the kitchen he nearly collapsed on the floor as he saw cabinet's doors open and things out of their usual spots. Mycroft did not care about his tea anymore. He was not enjoying that joke anymore and he was sure that his whole house had been messed around.

"Oh dear…" He mumbled as an overwhelming sense of uneasiness came over him.

Everything was out of place. Mere inches, yes, but nothing was at its exact place. The office room… He breathed out deeply once he saw the chair outside the closed door. He moved it away and opened the door. Immediately he grasped tightly the doorframe. Books were laid all over the floor and his desk was mirrored.

"Ah, Sherlock," He sighed, boiling inside. "you've come too far to play with me."

Would it be fair for Sherlock to prank Mycroft like this and expect him to do nothing? Of course not! Mycroft will set the scores right again in the next chapter.