"I may not have gone where I intended to go, but I think I have ended up where I needed to be." - Douglas Adams

John sighed and leaned for a brief moment into Sherlock with his shoulder. "How did we get here?"

When no answer was forthcoming, John turned to face his flatmate. Sherlock was clearly deep in thought - not mind palace deep, but apparently oblivious to John's presence all the same. The fingers of Sherlock's right hand were pressed to his lips, and his eyes roamed frenetically.

With a light touch, so as not to startle, John placed his hand on Sherlock's shoulder and spoke softly. "Hey... Sherlock. Did you hear me?"

Sherlock turned his face toward John and studied his friend with that arresting, assessing gaze. Taken aback by the sudden attention, John dropped his hand to his side, and jumped in surprise when Sherlock reached out and grabbed his coat sleeve near the cuff.

"John."

"Sherlock? Uhm... What the hell?" John looked pointedly at Sherlock's hand on his sleeve and then back up.

"It's something I've been considering for some time now." Appraising eyes still searched John's face.

"I'm sorry... What, exactly?" Shifting uncomfortably, John glanced over his shoulder.

"Your question. How did we get here. I've given it a great deal of thought." Sherlock adjusted the grip he had on John's sleeve, but didn't let go.

"Right. Good, yeah? Uhm... Wait... What?" Brows furrowed, John frowned in confusion. "Sherlock, I don't..."

"It just doesn't make sense, John."

"I agree." John shrugged and attempted a small, reassuring smile at his friend's unsettled expression. "It's fine Sherlock, really. D'you think..."

"No! John, you couldn't possibly understand." Sherlock released John's sleeve. A look of cold calculation settled over his features and he began to pace a tight loop, back and forth. John chuckled nervously as passers by gawked.

Tucking his chin to his chest, and lowering his voice so only Sherlock would be able to hear, John cleared his throat. "All right, Sherlock. Out with it. What's got you so bothered? You're making a fuss for nothing."

"Am I?" Sherlock stopped abruptly, turned to face John, and took a step just a bit too deeply into John's personal space. "Because I can't make sense of it John. I've considered, to the precise moment, the timeline in question. Done exhaustive background research. Calculated the odds. I've run simulations, both virtual and in real time..."

"Simulations? Sherlock, what..."

Sherlock continued speaking without pause. "I've plotted the weather patterns. Examined the flow of traffic." He exhaled deeply and looked John in the eyes. "The only conclusion I can come to with any certainty at all is that had any variable deviated, even minutely - a thirty second phone call, a two degree shift in temperature, a simple misstep in a crosswalk - and this never would have happened."

"This?" John's expression softened from confusion to one of almost-but-not-quite understanding.

Rolling his eyes, Sherlock huffed in frustration. "This." He flopped his hand in an anemic wave between himself and John. "Had the conditions not been perfect, we never would have met. You could have missed meeting Stamford. Or I could have stepped away from the lab. One or both of us could have died that day."

John winced at the plausibility of that statement. "God, Sherlock."

"It doesn't make logical sense. I've tried."

"Okay, just... Just calm down." John lifted his hand to place it on Sherlock's bicep, but hesitated, clenched his hand to a fist and shoved it into his pocket. "What's the sticking point? Is it the narrow window of time?"

"No no no." Sherlock shook his head emphatically and ran a hand through his hair. "That I can explain. There was absolutely no margin for error in the timing, but it turns out we didn't need it."

"Then I... I'm sorry, Sherlock, I guess I don't understand..."

Sherlock groaned. "Fine, I'll spell it out. I have spent most of my life making poor choices. I am selfish, rude, and disagreeable. An addict and sociopath. I do not care about people or the things people care about. I never had to work to earn anything, I only took that which would best serve my purpose. In general, I'm an arse. I know this." He paused and waited for response. John simply cocked an eyebrow and blinked back at him. Sherlock huffed a breathy laugh. "Right. You, on the other hand, made admirable choices. Choices that placed others above yourself. You sacrificed everything you'd worked up to for the good of others. You are compassionate, honest, generous, strong..."

"All right." John held up his hand and ducked his head, a blush creeping over his face. "C'mon."

"It's true, John. All of it. And the sticking point, as you called it, is that you, the bravest and wisest man I have ever known, were only in the park that day because you weren't doing the thing you'd worked your whole life to do. And it wasn't your choice. That fate was forced upon you. Where I, the addict who concerned myself only with my next hit, who barely managed to crawl out of the gutter, and then only with help I didn't deserve, was in that lab doing the work I love, but that came at no real personal cost to myself."

Sherlock looked away only long enough to gather his thoughts. He took a deep breath and turned back to John. "It never should have happened. You meeting Stamford in the park. Me being in that lab. You were meant to be in Afghanistan earning promotions and commendations. And I... well..."

"But it did happen." John's mouth quirked into a lopsided grin. "Just a lucky coincidence, I suppose. And here we are, both of us the better for it."

"Coincidence." Sherlock sneered. "The universe is rarely so lazy."

"You know, I never understood what that meant. Am I to believe Sherlock Holmes believes in a higher power? For someone who values logic above all else, you're attributing an incredible amount of authority to the universe."

"It's not a simpleton's regard for deity, if that's what you're thinking. But a need for order. To know that random is never truly random, but that every outcome, no matter how nonlinear, is the result of some prior action." Sherlock stared at John with an imperious look.

"Chaos theory? Really? So, we're friends today because of some... galactic hiccough..."

"More or less."

"And that would be easier for you to accept than the idea of an almighty, or even just happenstance?" John peered up at Sherlock, his expression completely guileless and open.

"Nothing else even remotely makes sense."

John smiled and shrugged. "All right."

Sherlock took a step back, eyes wide in surprise. "All right? Really?"

"You're Sherlock Holmes. If you say a space slug sneezing a billion years ago caused some sort of rift in all of space and time resulting in the two of us meeting, then it must be so. Though I'm none too happy the bloody wanker got me shot." John bit the inside of his cheek and had to look away to maintain his composure.

"Idiot." Sherlock laughed outright. "That's not what I meant, and you know it."

"Well, today is full of misunderstanding then." John chuckled as he took another look around. Sherlock frowned. "When I asked how we got here, I meant..." He gestured broadly to their surroundings.

"It's for a case, John." Sherlock crossed his arms over his chest and turned in a full circle in order to once more catalogue any detail he may have missed.

"Yes, I understand that, Sherlock. But Lestrade told us to meet him at City and Suburban Bank." John tapped the bank logo on the floor with his foot. "This is the wrong bank, which I find alarming since you have the entire city mapped out in that great mind of yours."

Sherlock hummed his acknowledgement. "I see the source of your confusion now." He leaned down to speak directly into John's ear. "Do you have your gun?" John jerked his head around to stare at Sherlock, but then nodded slowly. "Good, good." Sherlock kept his voice low. "Lestrade wanted us to meet him at the scene of a crime that has already been committed." He pulled his mobile from his pocket and sent Lestrade a text.

"Sherlock." John's tone carried a hint of warning.

"Is it not vastly more useful for the MET to have some men on the inside, to intercept their suspect in the actual act?" Grabbing John by the elbow, but maintaining a casual demeanor, Sherlock steered them behind a decorative pillar. "Have you ever been inside a bank during a robbery?"

"Bloody hell, is he here now?" John whispered as his hand went instinctively to his lower back, not to retrieve the Sig, just to feel it's reassuring outline.

"There are three. Male, blue suit with the newspaper. Female, red hat waiting in the queue. Male, green tie, he's the manager, and likely the mastermind." Sherlock glanced around once more.

Newspaper flicked the pages shut with a snap. Red hat opened her purse.

"Get down." Sherlock dropped to a crouch behind the pillar and pulled John down by the back of his coat.

"If I ever come across a space slug, I'm squishing it." John grumbled as the bank manager started shouting instructions at the tellers while tossing red hat and newspaper the guns he'd hidden in one of the tills.

"Well, until then, would you be satisfied squishing the human equivalent?" Sherlock quirked a mischievous grin.

"Oh god, yes."