A/N: I apologize for any inaccuracies for the medical descriptions in this piece. I tried my best, but am not an expert. Please let me know what you think of this fiction. Your reviews make my day!

The moment was only of a split-second duration, but its effect was pivotal. Lightening fast, Sherlock pulled odd bits and pieces from deep within his Mind Palace, and puzzled it together.

The puzzle was still missing vital pieces, but had enough detail to get Sherlock rearing to go. He would have to proceed with as much cunning as he possessed, if he wanted to get information from Mycroft Holmes himself. Closely-guarded, long-concealed, personal information.

Perhaps he had been too optimistic, or more likely, naive, when he had assumed that things were different now, three years after Sherrinford. Yet, here was his brother, doing it again.

His eyes narrowed in concentration as his brother righted himself and carefully planted his umbrella at his side.

"Do keep me informed of any progress as promptly as possible, Sherlock. The Holdersons tend to be quite slippery, if you get my meaning. I trust you will lend your assistance in this case, Dr. Watson?"

John accompanied Mycroft to the door, the British Government's steps unusually light and jaunty. After the small, almost infinitesimal, incident before, his actions served to set off even more alarm bells in Sherlock's head.

It was only after the Holderson case was solved (it had included a bullet nearly grazing Sherlock's skull, and a short-lived kidnapping of Dr. Watson, all pretty dull and routine, Mycroft never did give him the exciting cases), that Sherlock began working on his plan.

He got some recommendations from his blogger about the best sites to get information. Of course, he vaguely mentioned a case, involving an alibi and an exoneration. Par for the course, and John hadn't shown any further interest.

As he narrowed down the options, Sherlock felt resentment build internally. His big git of a brother never learned. Not even after all that had happened. As he raged inside against his brother, some part of him raged against himself, for being such an idiot, so oblivious, so blind. He silently fumed at the way his brother had played him. His revenge would come, but it would be bittersweet.

"I'm going out," told his partner, winning his scarf around his neck.

"Anything interesting?" the doctor asked.

"Mycroft." Sherlock's face twisted into a grimace. "I suspect he's hiding something from me, and I intend to find out what."

"Sherlock," the doctor said with exaggerated patience. "Mycroft is always hiding things from you. You know he can't discuss certain things even when he does want to."

"Not this time. He thinks he's being clever, but I've caught him." Sherlock smiled grimly.

"Alight, go ahead and try to outsmart your brother. But please, don't do anything foolish. It will be exceedingly inconvenient if you get yourself arrested for fratricide. I'm not in the mood of cleaning up all your experiments."

Sherlock was gone before the good doctor had even finished speaking.

Anthea had the gall to tell him that Mycroft was unavailable at the moment, and was there anything she could do for him?

Sherlock heard his brother speaking on the phone from behind the closed door. From his tone of voice, it was a routine phone call made to a very dull, hardly significant party. Pity. The detective would have loved to see his brother's face when he interrupted his call to a VIP, perhaps with the Queen herself. Well, he would at least be surprising his brother in a different way.

He got in with a key (the twenty-fifth one he had swiped, those paranoid gits kept changing the locks). Mycroft excused himself to the other party and put down the phone. He turned his fiercest glare unto his brother. Things seemed to be going according to plan.

"I have some sensitive information downloaded in here," Sherlock said, pulling out a memory stick and waving it in the air. He casually threw it towards the scowling man, shouting, "Catch!"

Mycroft reached out and missed, while his brother scrutinised him intensely. He bent down and picked the stick up from the floor, and straightened up slowly. Sherlock then asked him for a related file, and Mycroft made a motion to pick up the phone.

"I saw Anthea stepping out before, so you might as well give it to me yourself," Sherlock told him impatiently.

"Brother mine, I do have some minor issues to take care of, regarding my minor position in the government, and I just don't have the time to go rooting around for files. Wait for Anthea," his brother snapped back.

"Really, you have become even more indolent then ever. Give it to me or I'll take it myself," the younger man threatened.

With a sigh, Mycroft slowly picked himself up and made his way to the file cabinets, taking his umbrella in hand. He located the file and winced when he dropped it on the floor. Sherlock picked it up and sat down in the seat opposite Mycroft's, and waited for his brother to sit down. He watched him support himself on the desk before he sat down with awkward movements. Sherlock looked at his brother in silence, not saying a word.

Mycroft swiped a hand across his eyes and then stared at a spot on the wall. "This wasn't about the file, or the memory stick, was it, Sherlock?" he asked in a quiet voice.

"No." The one-syllable answer contained all his suppressed rage, disappointment, and fear.

Mycroft seemed to be concentrating intensely on the spot on the wall, as if the secret of the universe was encoded there. "Go ahead," he said eventually. "Tell me what you have deduced."

"Multiple sclerosis, of the Relapsing-Remitting phenotype." Sherlock's tone was matter-of-fact, as if into explaining a technicality of a crime.

Mycroft neither confirmed nor denied, merely cocked his head as an invitation to continue.

"Twelve years ago, you took to walking around with an umbrella at all times," Sherlock launched into his typical rapid-fire deduction-mode spitting of information. "You must have been experiencing mobility issues. An umbrella was the perfect compromise, as a cane would have been too obvious." Sherlock picked up the umbrella and studied it. "Ergonomic handle, broad tip, extra sturdy."

He planted the brolly tip-down on the floor, as if testing it. "You've had long periods since then when you were completely fine, as witnessed by myself. Nevertheless, you kept the umbrella as a prop, so your periods of illness would be less congruous.

"You've avoided unnecessary interaction during those times with those you've wanted to keep in the dark, which is almost everyone. Nevertheless, it wasn't always possible. I may not have put the dots together until now, but I remember several incidents."

Sherlock proceeded to recount those times he remembered, the fatigue and tremors which had been excused with various explanations. The reluctance at those times to be seen by Sherlock in person. The increased delegation of "legwork" that Sherlock had always mocked as increasing laziness.

His slowed down a bit when he reached a particular incident and his voice turned contemplative. "When John called you to come, after he found me drugged up shortly after his wedding. I found you sitting on the steps. Not your typical position. You had to rest before you could go further. Then, when I pushed you into the wall, you looked about to fall over. You couldn't even straighten up until John put the umbrella in your hand. You wouldn't have stayed to get back your umbrella when you have other ones, unless you couldn't even make your way to the car without it."

Sherlock stopped suddenly, and then said in a voice so quiet that it was nearly a whisper, "I'm sorry." Mycroft turned to gaze at him in surprise, and Sherlock felt a pang of disquiet at the thought that, of everything he'd said, it was those two words that surprised his brother.

"When you visited a few days ago, you tripped over your own feet, and nearly fell." He steepled his hands under his chin in a template of introspection.

"That in itself wouldn't have meant a thing. What gaversion it away was the look of alarm on your face. When you straightened out, you were extra precise with your movements. You realized that I was watching you, and overcompensated with a light and confident gait, unlike your usual heavy tread.

"When my suspicions were raised, I tried to pull up all my memories of you in a similar situation. I researched conditions that affect balance and function, and corresponded to your symptoms. The diagnosis I came up with was the closest match, and I further tested you over here." Sherlock looked expectantly at his brother.

"You were on target with your deductions, I must admit. You do understand that it is best to keep it to yourself. At the moment, this doesn't affect anyone else in a significant way, and I have no wish for you to interfere further."

The cold-blooded response of his brother infuriated Sherlock, and drove away any spark of compassion he might have been feeling.

"WHY!" he roared. "WHY DO YOU KEEP ON DOING THIS! You keep us all in the dark, and expect us to go along like good little goldfish!"

"When I asked it keep it to yourself, I didn't mean you should announce it to all of Whitehall," Mycroft remarked dryly.

Sherlock dropped his decibel level, but was still seething. "You're a pompous, arrogant prat. You always have to stick your nose into everyone's business, and then you go and keep all your cards close to your chest. Do you think everyone else too dull and helpless to be able to deal with anything? What right do you have to hide this from your own family?"

"Sherlock," Mycroft said slowly, his voice pleading and looking honestly confused. "Why would it matter why I told anyone or not? This is not like the story with Eurus and Redbeard, that directly affected other people. This is a personal issue I'm dealing with, and as of now has no impact on others in the family."

"What about your work?" Sherlock persisted.

Mycroft sighed. "It's on a need-to-know basis."

"Lady Smallwood? Sir Edwin? Anthea?" Sherlock questioned, and Mycroft nodded thrice.

"Why not me?" Sherlock questioned, the hurt finally seeping into his tone.

Mycroft looked at him helplessly, unable to offer any words. Like a gunshot going off in the Diogenes Club, the answer hit the younger brother. Twelve years ago, Sherlock was a drug addict, who resented his brother and didn't appear to give a fig about his welfare.

Twelve years ago, Mycroft was caring for his psychotic sister, while desperately trying to keep the world safe from her psychosis.

Twelve years ago, Mycroft was protecting their parents from learning about their daughter's fate, and the extent of Sherlock's addiction.

Twelve years ago, Mycroft had no one to tell. Today, he still wasn't sure whether anyone would care.

"Is it... progressing?" Sherlock asked hesitantly, trying to keep his voice level. The last thing Mycroft needed from anyone was pity.

"I've been very lucky," Mycroft smiled wryly. "I've been mostly recovered after the relapses, which have been pretty mild, relatively speaking. There is always the possibility of developing the Secondary Progressive stage of the disease, where the damage done during relapses will be more permanent. The chances of that increase over time."

Mycroft put his hands under his chin in unconscious imitation of his brother. "I do have access to the most cutting-edge treatment, you know. I am fortunate as well that this hasn't affected my cognitive functions. I'm dealing with it, Sherlock," he told his brother softly, in a way that was clearly meant to be comforting.

"Well, you must be, as England is still standing," Sherlock commented drolly.

"What do you plan to do with this information?" Mycroft asked, with a touch of anxiety.

"Nothing. This is you choice, and I will respect that," Sherlock said. "If, and only if, you give me your word to let me know whenever I can be of assistance." He shook his head firmly as his brother began to protest. "No, this is non-negotiable," he added sternly.

The detective appropriated a bottle of scotch and two glasses from his brother's cupboard, and poured a drink for both of them.

"What's this for?" Mycroft asked, his lips quirking wryly.

Sherlock lifted his glass and toasted. "L'chaim! To life." His brother finally smiled fully and echoed the toast.

When Sherlock returned to Baker Street, he told John that the visit had been so dull, it was a waste of breath to even talk about it. Then he locked himself into his room with his violin.

John was confused by Sherlock's behavior, and knew him well enough to know something was very wrong. He expected to hear a mournful tune emerging from the room. To his utter bafflement, he heard the strains of a tune he had sang in his childhood, so many eons ago.

He hummed along quietly, "London Bridge is falling down, falling down, falling down..."

He wondered how those cheerful notes could suddenly sound so full of mourning.