A/N: The title of this work comes from the saying, "The road to hell is paved with good intentions."

Although there are only a few minor season 3 spoilers, this is set during His Last Vow, after the confrontation in 221B with Mycroft/Anderson/CAM. Despite how it starts out, this story is going to be focused on the Mycroft-Sherlock relationship.

John had only just paid his cab fare and stepped out onto the pavement when a black car with tinted windows pulled up beside him. To his intense dismay, the window rolled down to reveal Mycroft's assistant busily tapping away on her mobile phone.

Without bothering to make eye contact, she said, "Mr. Holmes has requested your presence."

There were a lot of things John wanted to say in response, like

I do have a life outside of the Holmes brothers

or

Fuck off

But instead he got in the car without a word and waited silently as he was carried through the streets of London, until they stopped in front of a building—a building that looked suspiciously like someone's home.

No, this couldn't be—but still, John had to ask.

"Does Mycroft live here?"

Without even acknowledging the question, or looking up from her phone, she said, "You can go inside now."

Knowing better than to expect anything more than that, John stepped out of the car without a word and made his way to the front door.

Before he even had a chance to knock, the door opened, and he found himself face to face with an uncharacteristically weary-looking Mycroft Holmes.

"John, how good of you to come."

"Did I have a choice?"

Mycroft gave a tight smile.

"All the same, I appreciate your making the time to see me. I have some very important matters we must discuss regarding my brother. "

"I'm not spying on him for you."

"I assure you, that is not what I have in mind."

Mycroft paused for a moment, before asking, with clearly forced politeness, "Would you care for some tea or biscuits before we begin?"

"No, thanks. I'd rather just get—"

John made a vague gesture with his hand

"Whatever this is—over with."

"As you wish."

Without further delay, Mycroft led him into a sitting room.

"Please, have a seat."

Once they were settled into their respective places, Mycroft began.

"I'm sure I don't need to impress upon you the potential severity of this latest development."

"You mean the drugs? Or Magnuss—"

"Yes, the 'drugs,' as you so succinctly put it."

"Um, yeah, a bit concerning that."

Mycroft looked at John with the kind of expression that might be directed at a young child who had just said something particularly stupid or self evident.

"You are most fortunate not to have known Sherlock when he was caught up in the throes of his addiction. I assure you, if you had, you would be more than a little concerned."

"Fair enough." John hesitated, before adding, "But I don't really know what more we can do about it."

"Nor do I, which is of course why I asked you to join me here. I'm sure, between the two of us—"

"No—just, stop there. Sherlock is my best friend, but I can't be his around-the-clock minder. I have a job, and a wife who's about to have a baby."

John realized his temper was starting to get away from him, so he took a steadying breath, before continuing, with a more even tone.

"Look, you're his brother, and apparently you run this whole bloody country. I'm sure you can find a way to handle this."

"Believe me, John, if I thought Sherlock would respond positively to my direct interventions, I would be back at Baker Street this very moment rather than having this tedious conversation with you."

Reading the anger in John's expression, Mycroft hastily added, "No offense intended."

Then he continued, "But as you already witnessed, that course of action has not been particularly fruitful."

"You know, maybe if you went over there and talked things out, rather than getting people to spy on him and search through his things—"

"As reasonable as that course of action may seem, there is more to this situation than you could possibly know."

At John's challenging look, Mycroft elaborated.

"There was a time when I made a grave error in regards to my brother, and ever after he has refused to seek or accept my aid in any direct capacity."

"Have you tried apologizing?"

"I'm afraid that a few words of contrition will not be enough to resolve this situation. In fact, I believe the damage is irreparable. Sherlock has made it quite clear that he is unwilling to forgive me for this particular failure."

Mycroft paused, before adding, "And frankly, I can't find it in myself to blame him."

Given Mycroft's usual policy of nondisclosure, John did not expect further elaborations to be forthcoming, so he was more than a little surprised when Mycroft continued.

"You might find this difficult to believe, but there was a time when Sherlock and I were quite close—although that time has long since passed."

"I suppose it won't surprise you to know that we did not get on very well with other children. In that way, Sherlock and I were very isolated. I believe that isolation was damaging to him in ways that I couldn't comprehend, then and even now."

"It pained me to see him hurt by such petty scorn from those other children who were inferior to him in every possible way. I thought that I could protect him from future suffering by encouraging him to disregard caring and sentiment in the same way that I had learned to do, but over the years, I have come to question the wisdom of my actions. Still, I was but a child myself, and I did not see the ways in which he was damaged by our seclusion, nor how my actions amplified his isolation."

"Then again, we always have been so different. Whereas I am driven by practicality and reason, Sherlock is frequently controlled by the whims of his heart—although he often does not believe that to be the case. And yet, this was the boy who once dreamed of being a pirate."

Mycroft smiled, indulgently.

"Now, for my part, I was never prone to such flights of fancy. I did not have dreams. I made plans, although often quite ambition ones. Parliament, prime minister—at my most imaginative, maybe Secretary General of the United Nations."

Under his breath, John muttered, "No surprise there."

"Yes, well, I must admit that there were times where I tried to guide Sherlock towards what I considered to be more pragmatic—and respectable—career paths, but even at in those early days, my sway over my younger brother was very limited. And then there was—"

Mycroft paused for a moment, before asking John directly, "I don't suppose my brother has ever told you about Redbeard?"

"No, not that I can recall."

"Trust me, this is not a conversation that would slip your mind had you already had it. But I think, for the moment, it is best if I leave that particular incident up to Sherlock to reveal—or not—as he might choose."

His interest now piqued, John could barely restrain himself from inquiring further into this whole "Redbeard" business—especially in light of all that Mycroft had already chosen to reveal—but ultimately, he held back, afraid that if he pushed too hard, Mycroft might withdraw completely. So instead he stayed quiet.

It did not take long for Mycroft to return to his original train of thoughts.

"Let us leave it at this: the series of events involving Redbeard revealed to me beyond a shadow of a doubt the vast difference between the inner life of my brother and me. I realized there is a depth to his emotions that I couldn't possibly begin to understand. Although neither of us spoke of it at the time, I believe that was the moment when he first started drifting away from me."

"But darker days were yet to come. Because then—naturally—I went away for school. At the time, I saw it as the next, logical step in my education. However, to Sherlock, it was the worst kind of betrayal.

John couldn't help but watch the different emotions that played out on Mycroft's face as he spoke. He thought that he could read a certain wistfulness—maybe even sadness—in Mycroft's expression. There was something unnerving about seeing the other man appear so human, vulnerable, even.

"That was the first significant rift in our relationship, one of many unforgivable transgressions that I have since committed. In his eyes, at least."

"I know very little of what he got up to in those intervening years. I was away for much of that time, and even when I did return to visit, he was a closed book to me. Whatever connection we once shared had been permanently—irrevocably—extinguished."

"What I do know is that at some point during this period, Sherlock began his descent into addiction. I imagine it started innocently enough—a simple matter of youthful experimentation. Curiosity. Boredom. But my brother is not known for his impulse control—"

John let out a quiet, wry chuckle at Mycroft's understatement.

Mycroft initially looked startled—as if he had almost forgotten John's presence—although he quickly returned to a neutral expression, nodding his head in acknowledgment before continuing.

"Yes, not a particularly difficult deduction to make. And yet, I gather you found the thought of Sherlock Holmes as an addict to be incomprehensible when you first met him. It's certainly not a conclusion that I can fault you for coming to. After all, why would a man such as my brother—who values the function of his brain above all else—poison the part of himself that he treasures the most?"

"That is a question I have spent many sleepless nights seeking an answer to. I hoped, maybe, if only I understood, I could finally find out how to save him. If only I knew what drove him to destruction over and over again—because there were so many times when we nearly lost him. There were nights that I watched him sleep and felt my stomach lurch with every long pause between his breaths. Even now, I can still remember, in vivid detail—"

In that moment, Mycroft's voice falters, and he scrubs his face with his hand as if trying to erase the sadness from the lines of his face.

"Well, let's leave it at this: You were not the first person to witness the death of Sherlock Holmes."

Mycroft paused, gathered his thoughts, and then looked at John directly, and asked, "Have you ever 'done' drugs, John?"

"Me? Um, well—"

"Come now, no need to be demure. It's not as if I'll be recording this information in your personnel file."

"Wait, I have a personnel file?"

Mycroft continued as if he hadn't heard John's questions.

"But, so as not to make you uncomfortable, let's just leave it at this. There are many people, all of them assuredly far less gifted and intelligent than my brother, who dabble in this or that without losing themselves completely, never coming close to the depths that Sherlock reached in a span of a few, short, very dark years."

"After all, even I enjoy the occasional glass of wine, maybe a cigarette after a nice meal. What I cannot possibly comprehend is how any substance could be worth the lengths that he went to."

"Tell me, John, do you have any wisdom to share that might resolve this apparent paradox? You are a medical professional, after all."

John was so caught off guard by Mycroft's direct inquiry that all he could do was mutely shake his head, although even if he had been less taken aback, he likely wouldn't have been able to provide a more substantial answer.

Mycroft looked oddly deflated at John's response—or lack thereof—as if there had been some part of him that thought John might actually be able to offer some kind of clarity.

"Yes, well, I must confess that I was so desperate to understand that I once even tried the drugs myself."

John couldn't help his expression of shock, although he quickly tried to cover it up. However, Mycroft seemed undeterred.

"That really shouldn't be so surprising, now should it? You must know that I would do anything—absolutely anything—to keep my brother safe. And, of course, it's not as if I was 'shooting up' in a dark alley. It was done under perfectly scientific and sanitary conditions."

Clearly John's skepticism must have shown on his face, because Mycroft followed up with—

"Yes, I can see how it might seem foolish in retrospect. I hoped that it would enlighten me—that if only I understood his motivations, I could find a way to save him. But all I learned from that experience is that my brother and I are very, very different people. And I suppose I didn't need to dabble in recreational drug use to make that particular deduction."

Without thinking, John interrupted.

"People aren't puzzles. Even if you could understand Sherlock's motivations, it's not like you could just snap your fingers and make him sober up."

"You are, of course, quite correct in your assessment. I suppose at the point where I did my little 'experimentation' I was so desperate to find a solution that I was willing to try anything if it had even the slightest chance of helping him."

Mycroft paused again, gathered his thoughts, and then went on.

"While Sherlock is prone to hyperbole, it is true that I have a rather more—shall we say, elevated?—position in the British government than I may have initially indicated to you. Even still, with all of the considerable resources at my disposal, I was unable to protect Sherlock from his addiction and from himself, because make no mistake, Sherlock always has been his own worst enemy, as much as it pains me to acknowledge that fact. Even with all of the many criminal masterminds he has come up against, the greatest threat has always come from within."

"This, too, should not come as a revelation to you. After all, within 48 hours of first making his acquaintance, you shot a man to prevent my brother from voluntarily swallowing poison. And all for what? Not to solve a case, not to save a life—but because of boredom. A drive to be right. The need for stimulation."

"No matter how long he stays away from drugs, my brother will always be an addict. It's the only way he knows how to be."

John interjected again.

"You know, there are treatments available, places to go, even medications—"

"Trust me when I say that there is no avenue that I haven't explored, no expert that I haven't consulted, no cost that I have spared, in my search to find a cure for my brother's affliction."

"I sent him to the most expensive rehabs that money could afford—in London, the continent, even America. I signed him up for outpatient therapy and escorted him there myself. For awhile, I even moved him in to live with me. You can imagine what that must have been like."

John involuntarily grimaced at that prospect.

"But I didn't stop there. I had my 'people' track down every drug dealer in a 30 mile radius and pull them off the streets. Still, he always seemed to find another avenue to replenish his supply. I eventually hired guards to keep watch—but he always got away."

"I tried anything and everything. Left no stone unturned. And yet, none of it worked."

Mycroft's entire body seemed to slump over—subtly, yet unmistakably—as if he were reliving that terrible, painful moment of defeat.

"So I let him go. I watched him destroy himself. I looked on as he spiraled further and further into addiction. I witnessed my brilliant younger brother become a hollow, empty shell. With every passing day, I felt a part of myself die too. Then, finally, when he came to me again, asking for help, I—"

Mycroft faltered for a moment—looked down at the floor—before finding the words.

"I turned him away."

John couldn't help but flinch at Mycroft's confession.

"Yes, in retrospect, it is so easy to see the foolishness of that decision. But at the time, we had already been through this countless times, and I thought that, maybe, if I left him to do it on his own, he would finally learn. So I turned him away—and he left."

The expression on Mycroft's face can only be described as haunted, and for one horrible moment, John wondered if the normally stoic man might actually lose his composure completely. But after a brief pause, Mycroft seemed to regain control.

"They found him—half frozen to death—on the bank of the Thames the next morning. He was revived and rushed to the hospital, released a few days later, and he's been clean ever since."

"In a way, I suppose it worked. After all, he survived in one piece and has gone on to create a relatively happy and successful life for himself. It is as good an outcome as I could ever have hoped for."

"And yet, this victory did not come without a price. Sherlock has never forgiven me for that lapse in judgment, and I can't find it in myself to fault him for his anger. I thought I was doing what I had to in order to save him, but now I realize that was the night when I lost him forever."

"So you see, Sherlock will not accept help from me. But you—he would never turn you away."

John started to object. "I don't know about that—"

"I do."

"Even if that's true—and I'm not saying it is—what makes you think I'll be able to help him? If all your methods failed—"

"You are too modest, Dr. Watson. Here you are—a soldier and a doctor. A veteran of war. A good man, and a brave man."

John opened his mouth to protest again, but Mycroft held up a hand to stop him from speaking.

"More to the point, I know with absolute certainty that you are the one person Sherlock trusts completely—dare I say, the only person he has learned to love fully and without reservation. This makes you uniquely suited to offer such aid, and, as much as I wish this weren't so, you are certainly in a far better position than I ever will be to help him."

"I know it is unfair to ask so much of you, but I find myself in this position nonetheless. I would gladly provide you with wealth or prestige in exchange for your assurances on this matter, but I know you will not accept, so I will not offend you by offering. Instead, I am relying on your loyalty, compassion, and affection for my younger brother. For all his many faults, I know that you care for him deeply."

Mycroft paused and averted his gaze, staring off into the distance.

"John, if ever there is a time when he comes to you for help—no matter how inconvenient the timing, no matter how difficult or infuriating he may be—you must not turn him away."

Mycroft sighed deeply, before making his final plea.

"Please, for Sherlock, learn from my mistake."

A/N: I hope you enjoyed the first installment of this story! I certainly enjoyed writing it. I will definitely be continuing this story arc. There will be at least one more chapter that involves a confrontation between Sherlock and Mycroft, set in the season 3 timeline. I'm also going to be posting a work in this same universe that will include "flashback" vignettes of the days of Sherlock's addiction. I've started bits and pieces of both these continuations, but it may be a while before I get anything posted.

In the meantime, if you enjoyed this story, I have a couple more Sherlock and Mycroft-centric fan fics that you might want to check out (Go Fish, Atonement, Ch 1 of Hamish). And if you have a few spare moments and are so inclined, please leave a comment. Getting feedback on my writing makes my day :)