JOHN: She has really done her homework, Miss Riley – things that only someone close to Sherlock could know.

MYCROFT: Ah.

JOHN: Have you seen your brother's address book lately? Two names: yours and mine, and Moriarty didn't get this stuff from me.

— The Reichenbach Fall

Mycroft was far away.

Mycroft was at university and Sherlock in high school.

He didn't like school. School was abundant in absurd rules he abrogated, abominable teachers he abased and abusive students he abhorred. He didn't like school at all.

He missed Mycroft. He missed Mycroft a lot.

Letters were written, puzzles exchanged and issues resolved. Sherlock wrote about his unremitting boredom, his brilliant deductions and new scientific findings. He wrote about noises in his head. Mycroft replied with challenges, criticisms and taught him how to quiet those noises - and they did, the chaos rampant in his head subsided when Sherlock read his brother's letters, or simply as soon as he saw the quick, slashing handwriting featured so well in that expensive black ink.

Mycroft mentioned the mind palace in his letter and Sherlock started building one. Sorting things out and archiving them away helped, but his brain's last line of defense against itself also shattered as signals that he had a mind palace to retreat to let his voracious and ferocious mind loose. He lost control of his own mind. And the only one who really understood and could help was far away.

He needed Mycroft, at least before he could meander freely without getting lost in his own mind palace. His brain was marvellous, but like countless curious creatures in nature, it released poisonous chemicals - and Mycroft was his antidote.

It was Sherlock's turn to go to uni, and Mycroft gave him a phone, a mobile phone, wrapped in a box, sent to his dormitory. He didn't know how Mycroft could possibly afford it. He didn't ask.

Opened the box. Turned it on. Pressed the button. Address Book. One name. Mycroft. An eleven-digit number. Dialed the number. Beep. Beep. Beep.

"Sherlock?"

It was Mycroft. Familiar voice. His name. His name being called out by the familiar voice. Although the owner was hundreds of miles away.

He didn't say anything. He hung up.

Mycroft was nearby.

No, but Mycroft was still far away.

He lost his mobile phone after three months' ownership, because unsurprisingly, university was yet again teeming with abusive morons. He was beaten, black and blue. And red, red blood oozing from his wounds. But he called it luck - at least no bone was broken, and most importantly his brain was still intact, still able to dissect the tilting world with surgical precision. He smirked, and his swollen lips ached.

He didn't tell Mycroft, didn't call for four weeks. He wanted to replace it using his own money. He thought of stealing, conning, gambling, and even prostituting. But he didn't.

University was no better. Mycroft was absent. His mind was chaotic. His body, as if answering to his brain, was running a high fever. He felt cold and hot at the same time. Unbearably cold. Intolerably hot.

He went to Mycroft's on the fourth Thursday night, barely registering the raindrops falling on him.

Mycroft opened the door and immediately pulled Sherlock in, hugging him tight, tighter, without a word. His bespoke suit was dampened but he didn't seem to give a care, only then did Sherlock noticed the rhythm of the rain lashing at the windowpanes. Sherlock's knees went weak, as if after supporting his heavy body for so long, they finally consigned the task to the arms where he belonged. Warmth. Coolness. Mycroft. He felt better already.

"Mycroft, it's too noisy." He whimpered.

"I know Sherlock. I know. Sorry I was not with you." Mycroft soothed.

Only on rare occasions would Sherlock use the word to describe his stolid brother but this was one - Mycroft was scared. So they kissed, and kissed, until the affection and the sweetness vanquished all their unreasonable anxieties, until the noises were silenced and they were both reassured, but they kept on kissing, because they found it wasn't enough - it would never be enough. His brain was hyperactive, but like myriads of matters reacting in combustion, it was liable to suffocation - and Mycroft was his oxygen.

They never broke contact that night. And for the whole weekend, Mycroft walked Sherlock through in his own mind palace, reconstructing unstable structures and revising unsystematic designs, their hands holding tightly together.

On Sunday, Mycroft took him to a mobile phone store and bought him a new one, this time with messaging service.

Sitting next to Sherlock when the chauffeur drove them back to university, Mycroft took out his own phone and hit a speed dial.

"My number." Mycroft said as Sherlock's phone rang, "You might want to save it."

Sherlock shrugged and rejected the call, "I can memorise." he said, "I don't have to."

"Do you want to try the text messaging then?"

"You text me." Sherlock demanded, and Mycroft grinned.

When Sherlock got back to his dormitory, his new phone buzzed.

One new message. Read. From a familiar eleven-digit number.

I love you Sherlock. M

He smiled. Mycroft was nearby.

Sherlock liked to text. He couldn't call at any time but he could always text.

The three guys who beat me made it to your file I presume. They never dare to be within ten meters from me. S

Natural conclusion. They damaged my property and I am not a lenient man. M

And what exactly is your property? S

The phone. And you. M

Sherlock felt safe.

But it came again, the frantic whirring of his own brain. A cross he had to bear. A price he had to pay. He couldn't think. The deafening noises, the blinding lights and the endless corridors. Find a sanctum. Find the sanctum. Where was it? Where did he build it? He got lost in his mind palace again.

He went to Hampstead Cemetery. The leaning tomb. His bolt hole. He needed space and peace. Nobody was around, but the silence exacerbated the noises in his head, making them even louder.

The world was collapsing and he had difficulty breathing. He couldn't go through this alone. He needed Mycroft, but he couldn't call - his voice would be heard and he might be caught, plus Mycroft was having a critical meeting at the moment. He wouldn't be able to answer for the next half an hour.

He took out his phone and dialed the eleven digits. Save. Name. Mycroft. OK. New message. To. Mycroft.

Find me Mycroft. S

Sent. He drew his knees up and wrapped both of his arms around them, burying his head down, waiting. How was he going to survive the next thirty minutes? Another thirty minutes and he could be with Mycroft. How? He paced back and forth in his mind. Think about Mycroft. Yes. Think about Mycroft. Find the mansion he built for the two of them. Don't panick. Find it.

The phone made a chime. How could it be? Only one minute had lapsed.

There was a small envelope icon on the screen, and a name beside it - Mycroft.

He looked at the name, the familiar combination of letters, the name he had whispered so many times on so many occasions, and would never ever see enough of. Mycroft. Yes this was why he saved it, he realised. There was an unspeakable but significant difference between the eleven-digit number and his brother's name. He felt secure seeing the name, knowing instantaneously that it was the man he loved so dearly, and needed so badly, the man who would always find him when he was lost, who would always be there for him. Numbers were meaningless and cold. Mycroft was important and warm, and at this moment, everything.

He knew at that point that no matter how many phones he was going to own, or how well he could remember his brother's number, he would always put Mycroft's name in his address book, he would always want to.

Read.

On my way. M

The noises relented, gravity returned and reasons revived, and he felt calm. His brain was refractory, but like legions of lesions he had borne in the last nineteen years, it was taken good care of by Mycroft, and he read the text again, serene and safe - Mycroft was nearby.

Note:

The leaning tomb in Hampstead Cemetery was mentioned in S3E3 by Mycroft as one of Sherlock's bolt holes.

SMS text messaging service was invented in 1992 and first commercialised in 1994, just about when Sherlock went to university. (Like anyone ever cared.)

Getting lost in his own mind palace was mentioned in Chapter 3 and Mycroft's file in Chapter 2. (Seriously, does anyone really care about things like consistency… or foreshadowing...)

/ Podficcing this chapter maybe.

/ I'll be depressed if I receive no reviews whatsoever. Just saying.

/ Oodles of thanks to someone-who-hasn't-decided-her-pseudonym, without whom I see no prospect of finishing this work.