John had had the knack for as long as he could remember.
It wasn't that he could become invisible, exactly. The laws of physics worked quite well in his vicinity, thank you very much. It was just that people tended … not to see him.
It had taken him a while to piece it together. When he and Harry hid behind the couch after accidentally breaking Mum's favorite lamp, he just counted himself lucky Mum had seen his sister first. He wasn't the type of boy who craved being the center of attention, so when his teachers would glance past him in the classroom, it never seemed that unusual. It's not like he couldn't make himself known when he needed to.
While it was one thing for a teacher's gaze to drift past you in a classroom full of other children, though, it was entirely another when you're sitting in front of an angry principal demanding answers. The man was so furious about the latest student prank (something about letting a goat loose in his office), he insisted on interrogating each one individually. John hadn't been involved in the prank, but the entire class suspected who was behind it. He didn't want to tattle, though, and dreaded the confrontation.
To his surprise though, as he sank into his seat, wishing to be anywhere but facing this angry man, Mr. Galdon's eyes just … skimmed over him. John watched him glance down at the papers on his desk and then buzz his assistant, asking for the next student. John was stunned. He hadn't done anything more than confirm his name and class, and … that was it? The door opened as Jamie Wilson slinked in and John barely made it through the door as it closed.
It was like they hadn't seen him at all.
Then there was that aborted attack when he was ten. He'd been heading home after school when he heard a pounding of footsteps behind him. He'd just had time to glimpse a group of older kids heading his way before he ducked into a nearby alley and looked frantically around for somewhere to hide. There was no way he could fight off five of them.
He was completely astonished when, rounding the corner, all of them ran right past him, shouting, "Don't let him get away!"
After that, he started experimenting. He didn't quite understand it, but when he needed to, it was as if he could hang a Don't-Notice-Me sign over his head. Anybody who saw him or passed him on the street just … wouldn't see him. Oh, they'd steer around him, and he never got sat on by someone thinking his chair was empty. It was just as if he were background, like an extra on a film set—there, but just part of the scenery.
He found that his range was limited to a certain proximity, or line of sight—he wasn't sure. He couldn't make someone forget about him during, say, a telephone conversation. His teachers might not call on him in class, but they always remembered to grade his papers, and never actually forgot he existed. (Though he did occasionally have trouble with them marking him absent on days when he was sitting right in front of them.) It wasn't entirely a conscious thing, often controlled by his moods or the size of the crowd, but he gained a certain amount of control over it as he got older.
By the time he went to Uni, he had mastered his knack of fading into the background unless he wanted to be noticed. It came in handy in the army, too. He managed to avoid being picked for extra push-ups or extra attention from his drill sergeant.. And he made himself so agreeable (and inconspicuous) to his mates, they never seemed to take offense.
His skill definitely came in handy when he was in Afghanistan. Being able to avoid notice in a hostile environment was a decided asset, and he found that, if he concentrated, he was able to stretch the effect to cover fellow soldiers in his vicinity. Not that concentrating was always easy, what with it being a war zone, and all, but John had impressive focus when he needed it.
It was just unfortunate that it failed him when he needed it most. He had been kneeling over a wounded private when a nearby explosion made him duck, swearing—a break in focus just long enough that the sniper on the hill suddenly had a very clear view of one, frantic army medic working over the injured man. And then, of course, the bullet through his shoulder blew away any possibility of John concentrating on anything.
Yet, he somehow managed to drag the two of them back under cover before collapsing. Bill Murray told him later that he had never been so startled in his life because he hadn't even realized John was there until he saw him bleeding into the dirt in front of him. All things considered, John was just as glad his concentration had wavered at that point.
The recovery process was hard for him. He'd gone from being one of the surgeons in charge to being just another patient, there to be moved around as necessary. He had never minded being overlooked, but being treated like an object bothered him and made him feel more invisible than ever. Not that the nurses and orderlies meant to minimize him. They were hard-working, devoted healthcare workers, but it was sometimes a little too easy to direct their patients where they wanted them to go. The army's inexorable machinery didn't help, either. Now that he was no longer capable of being a surgeon, the bureaucracy automatically kicked into the process of sending him home.
Suddenly, he had no choice, no say in anything.
For the first time in his life, he felt truly invisible.
By the time he returned to London, he didn't even need his gift to be ignored. A drawn, wounded soldier automatically caused people to avert their eyes. He walked the streets of London for hours to strengthen his leg and never drew any attention. Not until he walked past his old school mate Mike Stamford, who somehow saw and recognized him as he limped by.
Everything changed when Mike introduced him to Sherlock Holmes, a man so observant that John felt like, rather than looking past him as everyone else did, he looked at him and saw everything. His life, his history, his injury … everything.
It was unprecedented, and he couldn't keep the asperity from his voice when he asked, "That's it? We've just met and are going to look at a flat?" It wasn't that he disliked it—not at all—it was just a shock.
So, yes, when the next night Sherlock bounded out of the flat with barely a second thought for John, apparently invisible again in the chair, John had snapped at Mrs. Hudson. It hadn't been about his leg at all, more a complaint at being relegated to wallpaper status again. Which might have explained his relief when Sherlock came back to invite him to the crime scene.
Hadn't that been an experience, too? He'd happily faded into the background and watched in awe as Sherlock shared his deductions about the murder. John had never seen or heard of anybody as observant as this new flatmate of his. It was as if the man saw every detail, every nuance of the world around him.
Which, John admitted, made his abandonment at the site that much harder to bear. He was jostled by the police officers trying to do their jobs as he maneuvered the stairs on his unsteady, plastic-covered feet. He felt almost bereft as he limped past Donovan on his way back to the police tape, but he was philosophical. He'd been overlooked his whole life, after all. It's not like this was new.
Still, the abandonment hadn't made him feel any less like a ghost, he thought, as he made his way down the dark street. The feeling was only exacerbated when he began to be haunted by ringing phones as he walked by. This whole evening was unreal, and as an exercise in trying to be visible again, something of a failure.
It was only when the third phone rang as he passed, that he realized they were ringing for him. Somebody could obviously see him. He was almost disappointed when the voice on the phone drew his attention to the CCTV cameras. His knack had always been restricted to real, nearby people and had never worked on film. He wasn't surprised to hear that surveillance cameras could see him.
When the car pulled up, he got in meekly. The man on the phone knew exactly where he was. Even if he had wanted to befuddle the people in the car and could somehow obscure the CCTV cameras (which he doubted), he didn't want to become memorable to a person who was obviously powerful.
The rest of the evening was a blur. The conversation with the man with the umbrella—a man who seemed to have the same gift for seeing John that Sherlock had. The chase over roofs and through alleys for the cab. The so-called drugs bust where the police all seemed to completely ignore John, while Sherlock pinned him with that sharp gaze of his and asked piercing questions. And then the mad chase across London to try to find Sherlock before the killer could strike again.
Later, John had never been so grateful for his gift as when he stood behind the police tape, watching Sherlock and Lestrade, and hoping neither of them would realize who had fired the shot. Yet, he knew the exact moment when Sherlock glanced over and saw him. His cool eyes had focused directly on John as Lestrade's glanced past, trying to see what Sherlock was looking at.
And then, when Sherlock had immediately approached and congratulated him? John was grateful for having been appreciated, but it was the fact that Sherlock had seen him that made him want to bask in the warmth of his gaze.
Really, John barely needed to use his gift at all after that. Not that he consciously used it on a regular basis. His unassuming demeanor and natural modesty did most of the work for him. It was usually when either his mood swung toward actually feeling invisible or when he consciously worked at it that his gift came into play. Most of the time he was only "invisible" because he was standing next to Sherlock Holmes.
Sherlock was like a lightning rod for attention—all eyes automatically turned to him when he entered a room. It wasn't surprising that John's habit of fading into the woodwork wasn't noticed—not even by Sherlock. (John sometimes couldn't help but laugh that the man who prided himself on observing everything completely missed this.)
Tagging after Sherlock, helping him out, suited John. He was involved and busy without having to draw attention to himself. His first attempt to get a job at a local surgery was a disaster. He'd been so tired on his first day (and frankly longing to be left alone to sleep), the receptionist completely forgot he was there and never sent him any patients. (It was a miracle he hadn't been fired, but luckily the receptionist took some of the blame.) He'd used his gift on purpose to avoid that ASBO, though, when Sherlock's graffiti-making friend tried to stick him with his bag outside the National Gallery.
Unlike most people, Sherlock never looked through him—though he had an odd tendency to forget him when John wasn't right in front of him—leaving him out on the sidewalk outside crime scenes or ignoring texts about graffiti. Considering how little Sherlock seemed affected by his gift, John couldn't decide whether this was an odd reaction to it, or just Sherlock being Sherlock. Judging by his timely rescue when John and Sarah were kidnapped by General Shan, he was inclined to believe it was simply Sherlock's high-handed, self-centered personality asserting itself.
All in all, they made a good team. John's natural inclination NOT to be in the spotlight perfectly mirrored Sherlock's apparent need for it, and John's self-effacing attitude often let him hear and see things that came in handy for solving a case. People just tended not to see him as a threat—or as anything at all.
There was nothing he could do, though, against the very determined, very focused attention of Jim Moriarty.