I feel away when he isn't with me. Once I was self-contained and now there's somehow more to me. Now there's something to miss, something I'm leaving behind.

John had, quite simply, ruined him.

John had changed him in some way. He was different, altered. Those last moments on that rooftop were moments he'd replayed over and over. The agony of them was almost addictive.

It actually took him several days to process the barrage of emotion. He was feeling John's pain. That was empathy. That was something several very well-accredited psychiatrists had convinced his family he was absolutely incapable of experiencing. He'd never felt it before. Of this he was absolutely certain.

It was John's pain, so it could not be buried. He wallowed in it. He had earned it with his scheming. It was his to bear. Once the initial crushing force of it eased, he began obsessing.

Before John, a time Sherlock rarely chose to dwell on, he could be utterly alone for months and feel no press of isolation. Now it was suffocating. The silence seemed to ring in his ears so he left the telly on constantly to keep it at bay.

He watched programs that John used to watch and wondered if he was watching them, too. Everything he thought about related to John in some way now.

He'd only been allowed out of his hiding twice. Both times he'd defied orders immediately and went to catch a glimpse of John. First in the graveyard, where he witnessed firsthand what fruit his plans had born. Then once more as John sat in a pub with Lestrade, staring silently into his pint while the police inspector droned on about his wife.

Mycroft had been icy in the car ride back. But he'd given Sherlock what he'd asked for finally.

That evening when he entered his flat in the compound, there was an elaborate surveillance desk in his bedroom. It was a direct feed to all the surveillance Mycroft's people had assigned to John. And it was considerable.

Sherlock watched John, thought about John and did little else for quite some time. Before this he would have considered such a thing impossible, his mind couldn't possibly be content to dwell on such an ordinary person doing ordinary things.

But John was not ordinary and this was an obsession like no other he'd ever had.

The sound Mycroft's wingtips made on the marble floor let Sherlock know his diet was another failure, and at least a half stone failure, at that.

Sherlock was lying on said floor staring at the ceiling. Doctor Who was on the television and a laptop with a feed from John's flat playing was at his side.

Mycroft loomed over him, "Do I need to list how many psychiatric disorders you're meeting the criteria for lately?"

"23."

I despise pining. It's so pedestrian and pointless. My cognitive processes are suffering. I'm not allowing myself to write about John. Every time I do it goes on for pages.

"I told you caring is not an advantage."

Sherlock's gaze focused suddenly, laser-like and intent, "An advantage? No. I've never made that argument."

"Then you must understand the foolishness you're indulging in."

Sherlock smiled in a way that made Mycroft squint as though he'd never seen him before.

"It is a glorious foolishness, isn't it?"

After three months, Sherlock had determined several things.

He could now experience empathy for John Watson. He, in fact, felt many intense and complicated feelings in relation to John.

Said feelings were not diminishing with lack of contact. Instead they seemed to increase over time.

He had been experienced gradually increasing feelings in general since John had entered his life. It had started when John had killed for him for the first time. That had elicited feelings of…. gratitudecompanionshipconfusionexcitement

Getting back to John was the only possible future. Nothing else was worth contemplating. John's presence was now his only hope of regaining some degree of control over his cognitive processes. If John were present like he was supposed to be, Sherlock would not be feeling or thinking about his absence.

John, as a concept, should not exist.

I considered John ordinary until I tried to describe him on paper.

He accepts me. He likes me. He's my friend. These things have never happened before. That actually makes John completely and utterly unique in my experience.

I have been cruel to him and he should have abandoned me many times. He isn't Mycroft, he doesn't have basic familial obligation to force his hand. He forgave me. He came running when he thought something might have happened to me.

John would kill for me and die for me. His loyalty is unwavering. He is so much more than I deserve. This is humbling. This is my lesson.

Sherlock replayed their entire relationship from beginning to end, over and over. He reanalysed, reassessed and reconfigured all of John's space in his Memory Palace.

He found every moment where he'd done wrong. Particularly all the little ones he had not been aware of. In retrospection, John's microexpressions told of many moments of wounded feelings, deeply buried for the sake of friendship and harmony.

John had fed him a ridiculous number of meals. An average of two per day for a year and a half. (Save at least six days of them being apart in that time.) When he was on cases he would let the food congeal on the plate by his elbow. There were hundreds of cups of tea in his past, carefully made the way he liked them and set nearby. He almost always drank at least half of those… leaving the other half to grow cold and be later cleared up by John.

Sherlock had concluded that he was abysmal at friendship.

This resulted in an almost catatonic depression for several days. Then it occurred to him that this might be something he could improve his skills at with effort.

This had never mattered before. But now it did. Circumstances had changed and required him to adapt. He accepted the challenge.

"Oh, good!" Sherlock looked up as Mycroft entered.

Mycroft promptly froze on the threshold and looked around wearily, "What have you done?"

"Come in! I need to practice active listening. Tell me about your day and assess me on this form I've prepared."

Mycroft glanced at the printed form he'd been handed. It was a series of 1-10 scale ratings next to a list of descriptions, "'Do you make me feel understood?' Yes, Sherlock, however being understood by you is generally a discomforting experience. What are doing?"

"I'm improving myself. Tell me about your day." Sherlock sat up and stared at him.

Mycroft shifted uncomfortably, "Perhaps I can find you a professional to help with this… project. Though I am pleased to see you out of bed."

Sherlock glowered, "I'd like it to be known that I am restraining myself."

Mycroft's eyebrows spiked, "My, you are serious. By all means, don't develop a digestive ailment on my account. Might I assume this relates to John somehow?"

Sherlock picked up his violin from the side table., "I should have known you'd be the worst choice to practice on. Never mind."

Mycroft put his hands in his pockets and cast his face upward as if pleading for divine intervention. He closed his eyes, "Would you like me to send an assortment of servants in for you to torment with questionnaires?"

Sherlock plucked at the strings morosely, "Only if they aren't completely witless."

Most of them were completely witless. But Sherlock noted a slow and steady improvement in his attention span if he let them blather on at him for a few minutes. He tried to find interest, something about them to catch his attention.

The first few attempts were not successful. The first woman cried and the first man stormed out. The second woman punched him. But he slowly improved and even found one of the gardeners interesting. He hadn't expected that.

The gardener was 76 years old and from Haiti. He actually had compelling stories to tell instead of mindless, mediocre anecdotes. Sherlock began looking forward to their encounters. He wrote about this extensively in his project notes. He underlined the words at the end of the entry.

This is my next lesson.

When he'd run out of servants, Mycroft found his various employees and underlings, all of whom were very good at filling in forms already.

From this group, Sherlock found an additional 6 people he enjoyed listening to. Out of a total of 39 people, he'd enjoyed 7. This frankly was a shocking statistic to Sherlock, whom if asked pre-John if he'd liked anyone would have found the very idea ludicrous to the extreme.

However, that still left 32 people who were absolute bores at best and irritating at worst.

He had been mistaken. This slowly dawned on him and was processed and internalized. He'd written off the entire human race because of his life experiences. Now that he was having other such experiences, experiences he was actively seeking, his opinion changed. Yes, most people were pointless. But some of them weren't. Discerning one from the other required at least a few minutes of conversation and could not be simply observed from a distance.

People could, in fact, surprise him.

It was nine long months in the end. Nine months for Mycroft's people to ferret out every last one of Moriarty's connections. All the pieces found and collected, with no one left to bother John.

The day he finally allowed to go he spent hours unable to leave. He had waited so long he was actually frozen with inaction. He wanted to leap up, run immediately to the Brazilian Jiu-Jitsu gym John was currently attending class at (according to the monitors) and tell him it was all over. He was alive, they could go back to 221B and everything could be the way it had once been.

Instead he watched John defeat several opponents on the mats, shower, dress and leave the gym for his current flat. Then he watched John eat dinner while reading one of Sherlock's own heavy botany textbooks.

"What are you still doing here?" Mycroft asked from the doorway at some point.

Sherlock didn't look up, "I'm preparing. Go away."

He stood outside John's door for over an hour.

It was a cheap basement flat. The hallway smelled vaguely of mildew and cabbage. The light in the stairs flickered in a manner that suggested epileptics might want to avoid the vicinity.

John couldn't be happy here. He would be happy to return with Sherlock.

After the fight ended, anyway.

Sherlock braced himself, tightening his pelvic muscle to absorb expected blows. He'd considered wearing a mouthguard but figured John would avoid his teeth and jaw the way he always did.

His hand knocked almost impulsively. Three quick raps.

He heard John get up and approach the door through the paper-thin walls and almost ran. Every impulse he'd had since hearing he was free to go surprised him. He barely recognized himself in these moments.

Then John opened the door.