Disclaimer: I own nothing.

A/N: This chapter contains mentions of drug use.

When the time comes for Sherlock to go to university, Mycroft makes it his priority to make sure he's settling in all right. He's only been there a week, but by the state of his room, it looks like he's lived there for ages. He's made himself quite at home, as evidenced by the clothes and books and papers scattered across his half of the cramped dormitory room. Mycroft wonders how in God's name any roommate is going to put up with Sherlock's shenanigans, but it's none of his business, really.

Mycroft asks him how he's getting on, how his classes are, how he likes his roommate – all the usual things. Sherlock shrugs, giving non-committal answers, saying his teachers are all frightfully dull and the students are even worse. Apparently, all they care about is partying and shagging and sleeping in. He came to university to learn and everyone else just wants to kill their brain cells with as much alcohol as they can possibly hold. Sherlock flops back on his bed and heaves a sigh. He complains that school's barely begun and it's just so boring. He doesn't know what he's going to do with himself for the next four years, surrounded by imbeciles and sentimental domestic dramas that he doesn't give a toss about.

Mycroft wryly suggests that perhaps, with all of his free time, he should start a blog in which Sherlock, with his copious knowledge of social systems, can offer his fellow students advice on improving the quality of their pathetic lives. Sherlock glares at him, but seems to contemplate the idea for a whole ten seconds before shrugging his shoulders and beginning to pick at his fingernails. Silence falls over the room and Mycroft taps his umbrella on the floor, the noise resounding on the tile flooring. Though filled with clutter it may be, the room still echoes with a sense of emptiness.

Against his better judgment, Mycroft asks if Father has been by yet to see him. Sherlock snorts and rolls his eyes. Mycroft frowns at him.

"What's that supposed to mean?"

"My whole life he's never given a damn about me. Why should he start now that he's finally rid of me?"

Mycroft shakes his head. He should be surprised by Sherlock's utter apathy, but by this point, hardly anything Sherlock does surprises him anymore. He lets the matter drop, unwilling to start a war between them.

Clearing his throat, Mycroft suggests they make tea. After all, there's very little a good cup of tea can't fix… or at least cover up.

…

On a rainy Saturday in February, Mycroft makes an unplanned trip to the university to collect Sherlock for their mother's birthday. For several years now, Mummy has made an annual trip back to London in order to celebrate her birthday with her boys. It is the one day a year that she asks to see them, one day a year when she remembers that she has two sons who still need her and have never been able to forget the hole she left in their lives. At first, Mycroft was reluctant, with the way she simply disappeared from their lives and the emotionally devastation she left in her wake, but he obliged nonetheless, rationalizing that he could give a few hours a year of sipping tea and making polite conversation to the woman who gave him life. To him, it seemed a fair enough trade. Sherlock, however, has never been so amiable. He has never forgiven their mother for leaving and has always been furious that Mycroft forced him to give in to her ridiculous and unfounded demands.

This year is no different than any other year in terms of dreading the date, but Mycroft no longer , when Sherlock doesn't show up for brunch, Mummy is distraught. She blames Mycroft for not making sure that his brother knew when and where to be. Mycroft considers telling her that Sherlock is no longer under his control – as if he ever was – and now that he is at university, Sherlock is free to do as she pleases. Every scenario he plays out in his head ends with his mother weeping so Mycroft, ever the fixer, offers to fetch him and be back in time for lunch.

He takes a cab – never the tube – to the university and heads straight for Sherlock's dormitory. When Sherlock answers the door, he is neither showered nor dressed. In fact, he looks rather hungover – his face pale and his eyes red and watery. Sherlock grumbles and rubs at his eyes, confused as to why Mycroft is here, now, and why. Mycroft does his best to calmly explain that today was the day of their mother's birthday and Sherlock just yawns. With a barely concealed rage, Mycroft sends him off to shower and make himself presentable. Sherlock pouts, saying he's not a child, and Mycroft points him down the hall, shoving him out of the room with a towel and some soap in hand.

Once again forced to cater to his brother's timetable, Mycroft is looks around the room for a place to sit while he waits. He avoids the rumpled bed, not really caring to think about what might go on there, and opts for the desk chair. Shaking his head, the take the stack of books and papers out of the seat – honestly, how does Sherlock live in this pigsty? – and looks for a place to set them on the already disorderly desk. Unable to find one, he pushes the clutter aside just enough to set the books down, inadvertently knocking a flurry of papers to the floor. With frustrated grunt, Mycroft picks them back up and is about to set them back down when something catches his eye. There, hiding just under a corner of yet another stack of papers, is a shiny silver spoon, bowl dulled slightly in the middle. Mycroft's eyes narrow. He's not stupid. He knows the purpose of a spoon like that. He reaches out and pushes the papers aside, revealing not only the spoon in its entirety, but a small hypodermic needle as well.

Mycroft's heart pounds. He can't quite wrap his brain around this. He knows what he's seeing and can clearly draw the conclusions from the evidence that lies before him, but he doesn't want to believe it. He's still processing his accidental discovery when Sherlock comes back in the room, clad only in a towel. Sherlock immediately begins complaining about him moving his things when Mycroft whips around, brandishing the spoon in a clutched fist, demanding to tell him what the hell this is about.

Sherlock blinks at him, raises his eyebrows, and calmly tells him it's for cooking heroin.

Then, for the first time in years, Mycroft loses his composure.

"Heroin? My god… What the hell do you think you're doing? Don't you know how foolish this is? Do you want to lose your scholarship? Do you know what this stuff does to you? How stupid can you be, Sherlock?"

Sherlock rolls his eyes and tells him to stop being so melodramatic, it was just one time with some friends at a party. It's not like he does it all the time. What kind of an idiot does he think he is?

Mycroft inspects his face closely, looking for any signs that his brother is lying to him. In his line of work, he sees all kinds of men who lie for all kinds of reasons and have all sorts of tells, but Sherlock – his little brother Sherlock – has a poker face that might as well belong to the hardest criminal. His expression seems to have been carved out of granite. His eyes don't twitch, his breathing doesn't change, his pupils don't dilate. He looks Mycroft right in the eye and says he isn't using, isn't a drug addict.

Mycroft has to believe he's telling the truth.

…

Time passes faster than Mycroft can fathom. He receives a promotion at work and has an office and an assistant all his own. He spends more and more time at the office, feeling a bit like his father, but he has no family to go home to. Not that he minds. His unorthodox schedule leaves little time for a personal life and he almost prefers it that way. His job is enough for him. He enjoys what he does and, more than that, he is good at it. He's building a name for himself and that is the only legacy he cares about.

However, he does worry about Sherlock. Mycroft barely sees him anymore and when he does, he doesn't look well. His face is tired and worn; he's thinner than ever before and his clothes just hang on him. Mycroft worries. He asks how he is, but Sherlock could care less about making conversation. He simply stares into his tea and shrugs, grunting noncommittally as Mycroft holds a largely one-sided conversation. If he mentions their father, Sherlock just laughs sardonically, wondering why the hell Mycroft would ask him about that. As if he'd speak with their father of his own volition. How foolish of Mycroft to even think that he might do such a thing. Mycroft has never been able to understand why Sherlock hates their father so much. Admittedly, the man has never been a saint, but neither has he been a devil. It makes no sense, and Mycroft worries more.

Most of their meetings end in frustration, with unsaid words and worries. Mycroft knows something's not right, he can feel it, but he can't bring himself to ask. Mycroft knows better than to push Sherlock away from him too. Their family is so scattered, so broken, that he is unwilling to lose Sherlock any more than he already has. He feels that as long as he's there for him, whatever is going on in Sherlock's life can't be so bad. At least he has one lifeline to cling to. In the end, he must know that he's there for him… He must.

Still, Mycroft can't help but feel that Sherlock is truly slipping away this time and that fact scares him more than anything else in the world.

…

The unthinkable happens during Sherlock's final year at university.

Mycroft drops by unannounced one day, planning to take him out for dinner – he's still frightfully thin, and Mycroft worries he isn't eating properly. It's been weeks since the two of them have talked – Mycroft has been completely bogged down with work lately and Sherlock has been facing with his final examinations – and all he wants to do is catch up a bit.

A student lets him into the dormitory and Mycroft makes his way up to the third floor. Sherlock has switched rooms since Mycroft last visited – apparently after the fifth roommate demanded to be relocated, the dean had finally permitted him to have a single. It was better that way, Mycroft supposed, for everyone. He approaches the door, the last one on the left-hand side, and notices that it is unlatched. With a gentle knock on the doorjamb, Mycroft pushes it open and steps through. He is totally unprepared for what he sees, but in the mere second it takes for him to realize what is going on, he sees everything.

Sherlock, cross-legged on his bed, a rubber cord tied 'round his left bicep.

Sherlock's pale arm extended to expose the veins in the crook of his elbow.

Sherlock's fingers curled into a determined fist.

Sherlock's steady right hand holding a hypodermic needle filled with some unknown substance.

Sherlock's steely blue eyes unwavering in concentration.

Mycroft lets out a noise of surprise and for the first time, Sherlock realizes he's no longer alone. His eyes widen, but he carefully sets down the needle before rising to explain himself. Mycroft doesn't give him a chance. He promptly turns and walks out the door. He's livid, both at himself and his brother. Sherlock lied to him, was lying to him, is lying to him and he fell for it. He let himself believe what he wanted to believe and ignore what he didn't wish to see. He's as much to blame for this as Sherlock is. He should have paid more attention, checked up on him more, made sure he was clean.

But Sherlock lied. That wasn't his fault. That was on Sherlock. He made the decision to keep using. He made the decision to lie. He was the one who was hell-bent on ruining his life.

With those thoughts, Mycroft keeps walking, down the hall and down the stairs, refusing to turn back even as Sherlock follows him, calls his name. He storms out of the dormitory and doesn't stop until he's off the university grounds, until he's on the street, until he's safely seated in a cab, whizzing through the bustling streets of London. Only then does he realize what he's seen, what he's done. He thinks shouldn't have left. Shouldn't have turned his back. He was just so angry.

Mycroft scrubs his hands over his face and sighs. He takes several deep breaths and calms himself down, telling himself that it wasn't his fault. That he needs time to cool down. That Sherlock is capable of making his own choices.

And so is he.

…

That night, Mycroft comes home to a message on his answerphone. It's Sherlock, apologizing for what happened. He says he's sorry and yes, he's been using, but he's been being careful. He's only doing it to help him manage the stress of his exams. He says he understands if he doesn't want to talk to him, but he just wanted him to understand.

Mycroft doesn't understand, but he's surer than ever that he never understood Sherlock at all.

A/N: As always, reviews are appreciated!