Mycroft had found him, well, he had found a name at the very least.
Him, of course, being Arthur.
Mycroft had his people keeping an ear out for years. Watching and waiting for any sign of anyone at all that fit with what he knew concerning Arthur's personality. The fundamental things that he knew would go unchanged by time. Arthur had courage in abundance, for example, and he cared for people deeply and with a reverence. No, not just people he felt obligated too, for all humankind. God knows if he could, Arthur would single-handedly try to save the world.
Unfortunately, as it turns out, there are an insurmountable number of people who feel a duty to humanity and are very brave in their efforts to fulfill that duty. Mycroft had seen firsthand the realities of trying to sort through them all.
After all this time, after the memories of dreams and wisps of hope he had clung to for all these years, reuniting with his son might actually just come to fruition. He had to admit, at least to himself, that he likely never would have discovered this lead or would have even known where to begin looking for it, for that matter, if it wasn't for the Lady of the Lake.
One month ago, Mycroft had woken from a dream so startlingly similar to the one he had as a boy just before Sherlock was born, that he knew that there was no other explanation other than it to be the work of magic.
Mycroft found himself once again in the woods near the lake he had dreamed of so often as a boy. Each time before receiving new memories of his past. The little girl, whom he knew to actually be the Lady of the Lake, stood in a small wooden boat just off of the shoreline and out of his reach. She faced him as if judging his worth, as a warrior would size up an opponent, looking fiercer than any knight as she spoke in a terrible and awe inspiring voice.
"The Once and Future King has been spared once again for his bravery, Uther Pendragon.
He has but one more chance at a mortal life.
Find him.
The time of King Arthur is again upon us."
Everything was easy enough to discover after that. Naturally, he had immediately looked into military records first, then slowly spread out to other civil servants such as police officers to find anyone harmed in the call of duty. No civilians seemed to have heroically rushed into any burning buildings that week, which seemed to make things a bit easier, and quickly he found only two soldiers that had been discharged after being recently injured. Only one of them having been born in England and another having been born Stateside. Arthur would most assuredly have been born English, which left only one name.
It was the name, really. John Hamish Watson.
The problem that Mycroft was currently facing was that no one seemed to know exactly where John Watson was. Mycroft knew that he was seeing a psychiatrist located somewhere outside of Piccadilly Circus that he stopped attending last week and that his credit card had been used at Tesco in the West End two days ago. He would have to wait just a little longer, but after waiting for so long, he could surely handle a few more days.
-Across London-
"Solved it! Time to text Lestrade, I suppose. I mean really, any idiot could have seen that..." Sherlock thought, right before the door to the lab opened cutting of his train of thought and revealed Mike Stanford walking through the door with a blonde man. Sherlock knew by his previous conversation with Mike that whoever this man was he was supposed to be a prospective man to flat share. What he couldn't have told Mike earlier was that he was waiting for a very specific roommate, he was waiting for Arthur Pendragon and no other would do.