AUTHOR'S NOTE: This is my first Sherlock fanfic. So, sorry for any mistakes. This story is before the Fall, and Sherlock's family, including mummy, are kind of occ.
Usually disclaimer: I don't own Sherlock or any of it's characters, if I did then we wouldn't have to wait so long in-between seasons, though it is totally worth it.

Sherlock never really cared about family.
Oh he had no illusions about his family's wealth and power (to say that they had an exceedingly large amount of both was not an exaggeration), but he had never really payed much attention to all his cousins, uncles, and aunts. In fact, the only reason why he didn't delete all information on them in his mind was because it wasn't worth relearning every time he had to attend those awful family reunions. Of course, there were some family members that he just couldn't ignore. There was Mycroft, who simply wouldn't allow himself to be ignored. And dear Mummy, to whom Sherlock was still entitled to give some level of respect and obedience. Father was… no longer relevant. After all, it was a waste to spend precious energy thinking about the dead. Family required too many emotions and sentiments that frankly Sherlock didn't want to give to any of those people, who most fell under the classification of idiot. Sherlock allowed cases to occupy the space in his life that normal people allowed family to have. Who could blame him? Cases and puzzles were interesting, and his most interesting puzzle was Moriarty. Which was why Sherlock would almost admit to being caught off guard when Moriarty brought up the subject of family.

They had caught a lucky break.
After weeks of leads and dead ends, the consulting detective had managed to deduce where a major London gang negotiation was going to take place. Sherlock and John both infiltrated the meeting in hopes of dismantling the organization by finding out the gang leaders' identities. Sherlock slightly down played the gravity of their task to John (if the good doctor knew, he would insist on bringing in the police and that would ruin everything).
But one thing Sherlock had not been counting on was the presence of one Jim Moriarty. As soon as he caught sight of him, Sherlock knew that Moriarty had figured out their plan. His attendance was merely to spite the detective. Abandoning all other thoughts, Sherlock chased and cornered Moriarty on the roof of the warehouse where the gangs' meeting was suppose to happen. Unfortunately, Sherlock did not have a weapon handy, he had let John stay with his own gun. The case had been becoming increasingly dangerous, leading right up to the confrontation between the two consultants.

Moriarty leaned lazily against the roof's railing, looking at Sherlock with an almost thoughtful expression.
"You know Sherlock dear, I wonder how much you really care about Johnny-boy's well being."
"Is that a threat?"
"Oh come on, think about it. You take in a poor stray mutt like John into your home, but then, you really don't do you?" Sherlock only offers a blink back in response. Jim sighs and explains, "Let's be honest, your line of work isn't the safest and I am going to kill you, someday. So tell me, who's going to take care of Johnny when you die? It's a big bad world out there Sherly. Awfully cruel of you let a stray dog live in your home, and yet after everything, still leave him a stray."
Sherlock tired to let the consulting criminal's words go over his head, but his mind had been introduced to the scenario and was now going through the possible outcomes. "SHERLOCK!"
Somewhat relaxing at the familiar voice calling out behind him, Sherlock stretched out his arm for John to pass him the gun, only to find himself being bowled over by another ex-military soldier. He managed to get a quick glance at the man before his head crashed painfully into the ground. Sniper, most likely Moron.
"Till next time my dears!" came a smug sing-song voice somewhere above him. By the time Sherlock was on his feet, and John was by his side, Jim was nowhere to be seen.
"Next time I say we should call the police, we are going to call the police! Or at least Mycroft." John exclaimed frantically searching him for any injuries, "What were you thinking chasing after Jim like that? You could have been killed!" he murmured worriedly, unknowingly adding salt to the wound Moriarty had opened up. Sherlock barely paid attention to the rest of the evening, his mind relentlessly obsessing over the question of what would happen to John without him.

Later, sitting in his chair hands folded in a mock-prayer position, Sherlock began to go over the consulting criminal's words.
Obviously Moriarty cared nothing about John's well being, his words were only meant to put him off, but Sherlock couldn't help but realize there was some truth to it. What would become of John if, however unlikely, an "accident" did happen to him? Sherlock contemplated faking his own death just to see the answer to that question but ultimately decided against it (it would be better to save a stunt like that for another time). Still, who could Sherlock trust to look after John's safety? Naturally no one was better suited for the job than he was, but as he began to go over the options, Sherlock became slightly distressed.
Lestrade wouldn't do, he had his own family problems to deal with.
Mrs. Hudson was too old, though very motherly, John would probably try to take care of her, which would result in a failure of epic proportions.
John had no current girlfriends and had apparently given up on trying to have a stable relationship, having said something about "living circumstances being unattractive to most women", whatever that meant.
Feeling a bit desperate, Sherlock even brought Mycroft into perspective, and almost immediately dismissed the idea. Mycroft may be over-protective and watchful of his little brother, but Sherlock knew Mycroft wouldn't go out of his way to take care of Dr. Watson, with their relationship being only "flat mates".
Wait a minute, that's it! Suddenly jumping to his feet at his newfound realization, Sherlock began to pace around the room. Sherlock knew that the only reason why he always had more than enough money, enough clothes, and enough to eat (although he rarely ate) even though he was not on "great" terms with his relatives, was because of his connection to the Holmes family. For goodness' sakes! If he hadn't insisted on getting his own flat then his mummy would be forcing him to live with her. Conclusion: family "took care" of him even when he didn't take care of himself, the only way to insure John's well being was to make him part of the Holmes family.

There were two ways he could accomplish this, marriage or adoption.
Sherlock had no eligible female family members, and he really couldn't stand the thought of John being married to one of his idiot cousins. Of course, he could always just marry John himself though he had no romantic feelings for the man. John probably wouldn't be too trilled about that kind of arrangement either, no, if he wanted John to be a Holmes then it would have to be an adoption.
It wouldn't be that difficult to convince his mummy to approve the idea (he had noticed everyone being more at ease around him now that John was with him), and if mummy liked the idea, Mycroft would have no choice but to go through with it. His extended family might not be so eager at the new addition, but they would just have to accept it. Sherlock's side of the Holmes had always been the pack leaders, one would say, they might cast disapproving glances but they would never outright go against their decision. This only left one loose end of the solution, John Watson.
John was a prideful man, not too the point where it could be counted as a bad quality (because really John was a good man). But he did have…trouble, accepting what he would deem as charity. It was a mess just trying to get John to keep an expensive coat that he had bought for him. Sherlock had noticed his flat mate's own jackets were not doing their intended purpose of keeping John warm and had simply acted accordingly. He finally managed to guilt trip John into using it, by saying how it was his fault that John had lost his old favorite jacket when Moriarty kidnapped him. If John put up such a fight against a brand-new jacket, Sherlock could only imagine the resistance his flat mate would put up against a free entrance into the Holmes descendants.
After thinking it over for a couple more seconds, Sherlock decided he would go through with his plan, and simply just not inform John about it. Despite the new last name all other changes into the Holmes family would be relatively subtle, except for a check in from Mycroft every few days which they were both already familiar with. If John didn't ask, then Sherlock would never tell. With any luck, John wouldn't even notice.

Next chapter John finds out! Sorry Sherlock ;)
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