This story is inspired entirely by John's line in The Reichenbach Fall: "Well, it's a great location. The Jubilee line's handy." And from there, my imagination came up with this.

John didn't usually like public transportation, buses and the Underground and the like, but sometimes he had no choice. For example, this day, a miserable rainy day, even for London. No cab was showing mercy on John, which was the cherry on top of his pathetic excuse for a day.

So it was with a frustrated sigh that John ducked into a Tube station after far too long trying to summon unwelcoming cabs. He rode the escalator down to the platform, reflecting on his most recent plight. After returning to London from the war, he'd utterly failed to find a decent flat. There was one, a really excellent impossible-to-get place on Baker Street, he was interested in, not that his finances were capable of a flat like that. What he really needed was a flatmate.

The platform was nearly empty, just a few people on benches or standing around. However, one thing was different, even lively. A song echoed through the tunnel, and John, despite his dark mood, felt his spirits lift. It was a beautiful song, some classical piece he was unfamiliar with, but appreciated all the same.

Out of curiosity, John stepped toward the sound, out in the corridor between platforms. Somehow, he'd missed seeing the musician initially. Now, though he spotted him in seconds, and had to admit to being startled. The man holding the violin, though clearly homeless, was not at all what he had been expecting. Most homeless people he saw and then forgot immediately, their faces unremarkable and their existences invisible to the general population.

This man, on the other hand, was memorable. Not just his mop of tousled dark curls and pale skin, but the intensity in his face as his fingers tilted the bow and changed notes on the neck of his violin. The melody flowed from the strings, plaintive and somehow sweet. John found himself frozen to the spot, eyes roving over the man, ears soaking in the sounds.

When the song finished with a bold crescendo, and the violin lowered, John took a sudden deep breath as if he had been submerged in water and only now came up for air. Yet the inhale was not nearly as fulfilling as the music had been.

The man, whose eyes had been closed throughout the duration of the song, looked around, with a quick glance downwards at the open violin case in front of him. He seemed unconcerned by the meager smattering of coins inside it, and instead set about adding rosin to his bowstrings. John darted back to his platform before he could be spotted, and only then did he realize he had missed the train.

Somehow, he found himself not minding.

Several days later, John stood at the entrance of his new job - just locum work, but it was better than nothing - filled with indecision. He really did not want to head home yet; the bedsit he had was practically the opposite of welcoming. The pub was a possibly, but he really couldn't afford to get drunk, on both financial and physical bases. He sighed and glanced around for a cab. Well... perhaps there would be something on the telly...

However, no cabs stopped for him, so finally he threw in the towel and stormed down toward the underground. There was a mass of people there of course, being peak hours and all, so he shoved his way to a place on the escalator and followed the signs toward the Jubilee line again. As the escalator descended, though, music reached his ears again, and he found himself smiling.

The man was back, crouched against the wall with the violin in his hands, playing a cheery tune. John slowed as he passed, letting the crowd flow around him. He dug in his wallet and extracted a ten pound note and a fifty pence piece. Seemed he'd have to get some more money, but this would do for now. He knew he was in a tight situation, but he couldn't not give this man anything.

The fifty pence clinked as it landed in the violin case, and the musician opened his right eye a fraction. His gaze flickered to the coins, then moved up and unerringly found John, who found himself immobile under the man's gaze, though he had been intending to continue walking. His eyes were a flinty green, shining under the harsh lights above them. He raised an eyebrow.

"That's all I get?" his voice was deeper than John had imagined. The smooth baritone complemented the bright notes his fingers and hands were still coaxing into the air, even as he shifted much of his focus to John.

"Well, it was that or a tenner, and I still need to pick up a meal," John chuckled, leaning against the wall next to the man and looking down at him. The musician smirked, fingers flying as he held out a long, wavering note and gave a final flourish of his bow.

"I suppose I'll let it slide this time." He tugged the case toward him with his foot. John noticed his shoes, dirty and old. His clothes were too, and there was a shadow of a beard on his chin. Yet his accent, manner of speaking, even the violin's shine, made him seem a bit out of place.

"You sound too posh to be down here, playing for pocket change. You could probably play in a real orchestra."

He received another dubious eyebrow in response. "Do you know you said that out loud?"

John resisted the urge to blush as the man turned his gaze on him again. "Sorry."

A smirk. "No, it's... fine. Anyway, I could use the extra cash."

John eyed the money before it was covered by the violin. "That's maybe three or four pounds."

"Four pounds sixty-five actually. I've done better."

They looked at each other again as the case snapped shut and the man straightened. He was about a head taller than John, slender and lithe. And suddenly, facing that gaze from above, John felt the overwhelming urge to get out of there before he did something stupid and impulsive. Like ask the man his name, or if he always played that beautifully, or if he maybe wanted to talk to John some more with that voice.

Hold up there, Watson. Don't be a creeper.

"Well," he said hastily, lamely. "I'd better go."

He darted back into the crowd before the fascinating musician could reply.

The next day, though, John couldn't help himself. He'd taken the tube to get to work, had seen no sign of the violinist, and had spent the rest of the day being distracted by snatches of the song from the day before playing in the back of his mind. By the end of the day, he was frantically googling every variation of "classical violin pieces quick tempo" that he could come up with in between seeing patients. None of the results proved fruitful.

So that evening, he dashed down toward the Jubilee line as quickly as he could and froze near the escalators, straining his ears. He let out a sigh of relief as gentle string music floated up to him over the overlapping conversations and bustle of his fellow commuters.

The ride down the escalator seemed interminable, but finally he was skidding to an almost comical stop next to the performer, leaning as casually as he could against the tiled wall, as if he had not been obsessing about the man all day and then raced to see him.

He did not succeed in the casual front it seemed, for he was immediately treated to a rather snarky side eye.

"Good afternoon," the man's smooth voice was laced with amusement. John delayed replying for a moment in favor of watching the movements of the bow, bold and sure. This song was quiet, almost romantic in its tone, if John was understanding it properly. Then again, he was probably wrong, not exactly being a musician.

"What song were you playing yesterday?" he asked in lieu of a normal greeting. "I've had it stuck in my head all day, but I can't find it on the internet."

"You wouldn't have, as it's one of my own compositions. All the songs you've heard me play are my own."

John raised his eyebrows, incredulous. "What, really? That's brilliant!"

The other man smiled, and John couldn't be sure thanks to the poor lighting, but he thought he might be blushing slightly. "Is that all you've been thinking about today?" he asked, leaving a distinct impression of trying to save face. "You must not have had much else to do."

How true that was. The song was the most stimulating part of John's day up to this point; the rest had been boring and meaningless in comparison. He chuckled, self-deprecating. "Nothing happens to me."

The man glanced down, smiling. John soaked in this song - full of complex sounding runs and long notes - as he dug in his wallet for more coins. He came up with thirty-four pence, which he tossed into the case.

"Generous."

"Shut up," John laughed as he pushed himself off the wall. "It's all I've got at the moment."

The man nodded, looking up at John through his surprisingly long lashes. "Until tomorrow then," he said with what might have been a wink.

It took John the entire ride home to get the resulting smile off his face.

The next two weeks passed in a blur of tedious workdays, crowded tunnels, and music. John spent most days humming what snatches of the songs he could remember, making sure he had at least some change to toss into the violin case. Sixty-two pence here, a pound ten there, forty-three pence next, and so on. Each amount accompanied a song, and a brief conversation.

Sometimes it went something like:

"You're a doctor, an army doctor in fact."

"Been googling?"

"No, just observing."

"You'll have to explain to me how you observed that."

"Perhaps tomorrow, doctor."

Other times they discussed the music:

"I actually recognize this one. Bach?"

"Very good, Doctor. Your education was not entirely lacking in culture."

"Says the man who didn't know we don't have a king."

"Irrelevant."

"If you say so."

"Until tomorrow."

"See you, you berk."

Still other times were of an even more personal nature:

"Do I get to know your name yet?"

"Why would you need to know that?"

John huffed, amused in spite of himself. "Because calling you 'that violin bloke' in my head is getting a bit weird."

He looked abruptly uncertain. "You think about me?" He sounded completely thrown, as if it had never occurred to him that he might linger in John's mind along with his music.

"Of course. Why wouldn't I? We're friends."

"Are we?" he didn't seem dismissive or derisive in response to the idea, only startled. John wondered if he had ever had a friend before.

"Yeah," was all he could manage to say.

"Can people be friends if they don't know one another's names?"

John nodded. "Sure. But if it makes you feel better," he stood and dropped the coins into the case - forty pence this time - and began to head for his platform. "My name's John Watson."

The next day, Sarah, John's boss, caught him humming one of his favorite tunes under his breath during his lunch break. She smiled rather too knowingly for his taste, and he shifted uncertainly in his seat.

"What?"

"Who's the lucky lady who's got you all smiling and day-dreamy? And humming?"

John pressed his lips together, a smile tugging at the corners in spite of his embarrassment. "What makes you think it's a woman?"

She grinned and stood as the phone in her office next door began ringing. "You should bring him round for drinks with us some Friday night. We'd all love to meet him."

Right, great, but how was John supposed to introduce him? "Violin man"?

That afternoon John approached the entrance of the tube, already digging in his wallet for change. Therefore, he didn't see the hand reaching for his arm until it was too late and he was being yanked back into one of the narrow mews of the main road.

"What the-?" he cried out, whirling. It was the musician, clutching his violin and bow in one hand, the case in the other.

"John" he nodded. "I need your help."

"What? I don't und-"

But the rest of his sentence was cut off when the man cursed. John looked over his shoulder, following his gaze, and saw another person - bloke in dark jeans and a grey jacket - dart out of sight into the tube.

"Come on John!"

John barely registered the violin and bow being shoved into his hands before he was running.

They followed the unknown man at a breakneck pace, and John found himself dodging people as they leaped over the turnstiles and raced down the escalators.

"Wait!" he called ahead. "What are we doing?"

"Stopping him!" was the only reply.

John was momentarily stopped by a tightly-packed crowd, losing sight of both men in front of him. By the time he broke free and reached the main tunnel - conspicuously devoid of the usual violin music - he found himself alone.

Then, a scream echoed through the tunnel.

Ah ha.

He had barely reached the southbound platform when suddenly arms were around him, scrambling to put him into a chokehold. He cried out, but before he could fight back, the violinist was back, pulling the apparent criminal off. John spun about, gasping for breath, and watched in bewilderment. Then worry.

Despite John's friend being taller and quicker, the other was steadily pushing him closer to the edge of the platform. And judging from the sound whistling toward them, a train was on its way. So John launched himself forward, grabbed the first thing he found on the ground - which turned out to be the fallen violin case - and slammed it into the back of the man's head.

He dropped, unconscious, and by instinct, John caught him and lowered him to the ground. After checking his vitals quickly, he looked back up at the musician, who had straightened and brushed himself off as the train screeched to a stop. The platform had cleared of frightened commuters when the fight broke out, but now people exited the train and looked at them all curiously, particularly the prone man on the floor.

John stood and strode over to his friend, who was winced as he gently massaged his wrist. "Thank you, John," he gasped, breathing sharply.

"You alright?"

He nodded, shaking out his wrist still, then smirked. "You did well."

John laughed, a bit breathless himself. "You too. Now what the hell was this about?"

"Thievery," was all the man got out before tube security personnel appeared and dashed toward them.

"The situation is under control," he said quickly. "This man-" He pointed at the unconscious man sprawled on the platform. "-is a thief. His wares are stored somewhere around here."

"And who are you?" One security guard snapped. "Why should we believe you?"

"Sherlock Holmes, consulting detective. Contact Scotland Yard's DI Lestrade, he'll vouch for me."

The first guard raised his eyebrows in palpable skepticism, but the other quickly intervened.

"I've heard of him," she said, nodding. "What's going on, Mr. Holmes?"

Sherlock looked pleased. "For several weeks now I've been undercover. This man," he pointed at the prone form at their feet. "-is named Ryder. He's a thief I've been tracking." He fixed his gaze on the guards again, though spared an amused glance at John. "You have been unknowingly allowing him to get away with his crimes. Based on his shoelaces, the residue on his fingers, I suspect..." He stalked down the platform, fingers trailing across the tiled walls. Pausing at one area, he gave a cry of triumph, then popped out one brick. Thrusting his hand into the new gap, he carefully extracted a dirty parcel, which he tore open to reveal a pile of diamonds, rubies, what looked like a solid gold brick, and a large blue stone the name of which John didn't know.

Sherlock looked back up with a grin, almost childlike in the delight it portrayed. He twiddled the blue gem in his fingers, making the overhead lights glint off its surface. "This should be all of it then. I suspect Ms. Morcar will be relieved to have this back in particular. Thank goodness Ryder didn't hide these in the poultry shop; the smell was not altogether pleasant and I didn't much fancy a second trip there." He handed the guards the gems, ignoring their somewhat bewildered faces. "Get these to Scotland Yard when they arrive."

The guards sputtered through expressions of gratitude, taking the dazed and semi-conscious Ryder away. Meanwhile, Sherlock waved them off and spent several minutes on the phone with someone who seemed to be alternately called Geoff and Gavin. John, on the other hand, was relatively ignored. He did, however, spot the fallen violin and bow, near a bench. He couldn't even recall having dropped them, but was glad to discover they'd made it through unscathed.

He was carefully returning them into the case (now sporting a small dent on its side from its contact with Ryder's head) when Sherlock's footsteps approached. John looked up to find him smiling somewhat uncertainly.

"So," he said.

"So," John echoed, standing straight and handing over the case. "You could have told me you were undercover."

Sherlock shrugged, almost sheepish. "Apologies. I'm not good at... the socializing thing."

John chuckled. "Yeah, I gathered that."

They both fell silent for a moment, sizing each other up, not knowing what to say. John found himself longing to make him smile again, to check his hurt wrist, something, anything. Sherlock's case was over, so this was probably the last chance he had to see the remarkable man.

Sherlock pressed his lips together, then met John's gaze. "Sometimes I don't talk for days, John. Would that bother you? Obviously I can see you don't mind the violin, but-"

"Wait," John held up a hand. "What are you on about?"

"Well, potential flatmates should know the worst about each other." There was a delighted glint in Sherlock's captivating eyes as he spoke.

"What?" John raised his eyebrows in equal parts amusement and confusion. "You want me to live with you?"

"Yes," Sherlock replied. "I've already moved in, but I can only keep the special deal my landlady's given me if I get a flatmate. It's not far from this station, on Baker Street."

"What, really? I looked at that place briefly, but on my own the rate was too high. So you're not actually homeless?"

"Of course not," Sherlock looked smug. "Just undercover, as we've established. This was one of four likely places I believed Ryder to be hiding the stolen jewelry, so I've been staking it out each day, trying to catch him hiding anything."

"I'm sorry if I ever distracted you-"

"Nonsense," he waved a careless hand. "I'd have simply ignored you if your presence had overlapped with his. So, the flat? We'll meet there tomorrow, say seven?"

John began giggling in spite of himself. "We've only had probably about an hour's worth of talking over two weeks, we just took down a jewel thief together, and now we're going to go look at a flat?"

"Problem?"

John was still giggling, and he was delighted to see Sherlock starting to laugh too. "No, no, not at all. Just... this might be the most ridiculous thing I've ever done."

Sherlock shrugged, still chuckling. "I'm sure that won't be the last time you think that."

"I hope not." Despite his laughter, John was completely serious.

Sherlock grinned at him, considering him for a few moments as they both sobered. "Nine pounds eighty-four."

"What's that?"

"How much I'll convince my landlady to take off your first payment on your half of the flat."

"What? Why?" John chuckled, bemused.

Sherlock bit his lip against a smile. "It's how much you tossed in my violin case. In total."

John softened. Of course he had been keeping track. "You don't have to do that."

"Consider it a thank you. For... what you did earlier there on the platform... saving me from falling." Sherlock shuffled his feet a bit awkwardly. John smiled at the endearing sight. "It was... good."

"You're welcome," John murmured. He found he rather liked this less aloof version of his friend. "Dinner?" he asked. In for a penny... or in this case, about nine hundred pennies...

Sherlock looked up in surprise, that bright blush still spread across his cheeks. "Starving," he replied. Then, he smirked, a teasing sparkle in his eyes. "Shall we take the tube?"

John laughed and fell into step with him. As ever with the fascinating man at his side, he didn't know what to expect, but he was eager to find out.

Guys re that finale... I just gotta say... my favorite part might have been Mycroft's umbrella. Also I don't think I breathed at all the entire episode. Except to scream at Moffat for various reasons.

Hope you enjoyed! If you are so inclined, please leave a comment; I love comments.