It's hard to believe that a modern man like Sherlock Holmes keeps an Index. Not a scrapbook, as he acidly corrected John one morning, but a real, honest-to-God index. Of crime, of course, and of notorious criminals (caught or not) and his cases (solved, all of them, save one.) He said he liked the feel of the weight of it, tangible evidence of his work that he could hold in his hand. Literally, in some cases, as he sometimes pasted bits of evidence in there, and what didn't fit in the book went in various small boxes that he kept on a shelf in his bedroom.

So when John looks up from attacking a cucumber one evening, he isn't at all surprised to see Sherlock with his big book open almost to the end, writing, and with a big bottle of glue off to one side.

"Working on the case notes, are you?" John asks as he chops. They were home only one day from three days in Aberdeen, working a missing persons case that ended well, for once, with two frightened children being returned to their worried parents.

Sherlock rolls his eyes. "Your penchant for stating the obvious is astounding, John. Do you come by that talent naturally, or did you practice it?"

"Come by your smart mouth naturally, or was that a purposely acquired habit?" John retorts amiably, tossing a piece of cucumber at Sherlock and hitting him almost square between the eyes. The ends of cases were always like this, the crash at the end of the adrenaline high, and Sherlock was always more susceptible to dangerous lows the longer cases wore on. This one wasn't particularly bad, though; insults were par for the course, but at least he hadn't started smoking again.

Sherlock snatches the piece of cucumber from the table and lobs it back at John, who catches it easily and tosses it in the sink.

"All right, you, that's enough of that," John says, turning back to the board. "I'll not get this done if you don't stop distracting – damn!" John's right thumb suddenly blooms with bright scarlet, and he snatches a piece from the kitchen roll by the sink. Not too deep, just a quick slide of the knife across the tip of his thumb. Needs a plaster, though, and as John turns to fetch one, Sherlock's standing in front of him with the box. "Oh, thanks," he says, taking it awkwardly. He unwinds the paper towel, looking around for a place to drop it.

Sherlock reaches out two fingers and takes the towel, barely spotted with bright red blood, and tucks it in his pocket while he extracts the box of plasters from John's hand, pulls one out, and fixes it to John's cut.

"Thanks," John says. "Now you'd better eat that, 'cause I've bled over it. You've only had a packet of crisps since Tuesday, and I'll not be responsible for you dying of malnutrition."

"It's got mushrooms in," Sherlock says petulantly. "You know I don't like them."

John sighs. For all his brilliance, Sherlock really is a child sometimes, having to be bribed to eat his vegetables. Affection warms his voice as he says, "But I do. Pick around them and stop being an ungrateful brat. I did put pine nuts and blue cheese in, I know you like that."

Sherlock pouts for half a second until he catches sight of the colorful foil-wrapped packet in John's hand.

"Yes, it's almost Easter. Yes, I'll let you have it. If you eat your salad. And before you ask, no, you don't have to eat the mushrooms."

John never reads the Index. He's had to look things up before, and the few items he's skimmed through are enough to give him nightmares on their own, so he doesn't touch it if he doesn't have to.

Today, however, he has to.

"Dammit, Sherlock, haven't you ever heard of preservative?" John's opened to the "O" section, for Oppenheimer, head of a drug cartel. The page before has a small plastic bag attached to it, and whatever was inside has gone liquid. That little bout of unpleasantness should the bag ever break open is one John doesn't care to contemplate.

Sherlock looks over his shoulder at the offending item. "Oh, yes, I knew I meant to do that. Got away from me. A piece of Nathaniel's scalp. Well, it was. Perhaps I should bin it."

John presses his fingertips to the ridge of his brow and closes his eyes. Just one more thing to add to the list of things that could Go Wrong in the flat at any given time. "Don't tell me if there's more of that kind of thing in here."

Sherlock looks at John, wide-eyed and innocent. "I won't tell you, then," he says.

Sherlock starts keeping the Index in his bedroom after the scalp incident, to John's relief. There's only so much random necrotic tissue a man can take, after all, and if the inevitable happens, at least it will happen to Sherlock's bed and not on the living room carpet. It's a bomb, primed, ready to go off, in John's mind.

So it's with a lot of protestations and eye-rolling that he fetches it from Sherlock's room one evening.

"But you're on your way to the bathroom, and my room is right there," Sherlock cajoles."Quit being a coward and just pick it up on your way back. Injured, remember?" Sherlock holds his wrapped ankle up as evidence.

John shudders as he carefully lifts the now six-inch-thick binder from its resting place on the bookshelves near the door. All of the evidence boxes are there, too, lined up in row after row, with labels on them that correspond to the case number Sherlock assigned in the Index. It really is an ingenious system, John muses, as he nudges a box back into place that was disturbed by his messing about. All of the boxes are the same – around the size of a shoebox- save one, at the bottom, which is at least twice the size of the others. John doesn't think too hard about what evidence a box that size could possibly contain as he gingerly carries the Index back out into the living room.

"Here," John says, carefully placing the binder on Sherlock's lap. "Don't open it until I'm gone. Give me that foot and let me take a look, then I'll be out of your way and you can paste to your heart's content." John settles on the sofa next to where Sherlock is reclined, lifting Sherlock's legs and resting his feet on John's lap. He unwraps the elastic bandage and pushes the leg of Sherlock's pyjamas up to his knee.

The black bruising reaches from the top of Sherlock's foot all the way along the outside edge and around the ankle itself. At least a third degree sprain, John notes, as he gingerly slides his fingers along the tendons, noting the swelling. The small part of his mind that notices Sherlock's soft skin on the inside of his instep is tamped ruthlessly down as he flexes Sherlock's ankle slightly, which makes Sherlock hiss a protest. "Sorry," John mutters. His fingers follow the tendons around the back of Sherlock's ankle, up the Achilles and almost to the calf before he realizes both hands are wrapped around Sherlock's leg. He looks up, only to see Sherlock staring at him intently and holding himself very still, eyes dark.

John grasps at the last shreds of his professional dignity and re-wraps Sherlock's ankle with an efficiency that would make any battlefield medic proud. An awkward pat on the knee and John's up, across the room and in his chair in an instant.

"Four weeks, at least," John says. "And physiotherapy after. You'll hate it."

Sherlock doesn't reply, simply opens up the Index near the end, and begins to write.

John blames Sherlock's ankle for the situation he's now in.

Two men have him cornered in the back of a near-empty pub where John had simply gone to retrieve a message for Sherlock, and instead managed to get himself trapped by thugs who were waiting for Sherlock to come get it himself. John's current weapons are a lit kerosene table lamp and a pint glass. His throwing arm is pretty accurate, but he doesn't fancy burning the building down if he can help it.

"Just the messenger, boys," John says, brandishing his candle. "Why don't you go on, and we'll all go about our business like none of this ever happened." Thug One has a leer on his face that John doesn't think bodes well for his future, so he chucks the glass straight at Thug One's head, tries to duck under Thug Two's arm and gets an elbow in the eye for his pains. He manages to get between them and the door, though, so he makes a run for it, smashing the lamp on the step, creating a quick flare-up that gives him a few precious seconds to gain some ground. He ducks into the nearest underground station and collapses on the train, panting.

Sherlock's face when John staggers in the door is gratifyingly concerned, with a flicker of guilt in there to temper it. He closes his Index carefully, turning slightly in his chair.

"Knew you'd have friends waiting, did you?" John says, pulling the emergency cool pack from the freezer.

"Not knew, exactly. It was possible, but I didn't think it likely."

"A little warning next time wouldn't go amiss. Cheers," John says as he drops on the sofa and presses the cold compress to his eye. John tells himself this is the last, the absolute last time he'll go on one of these ridiculous errands for Sherlock; he damn well can do it himself next time. The problem is that John's told himself this a hundred times before, but Sherlock always manages to find a way around his protestations, wheedling John into doing him favors even when John doesn't want to.

He cracks an eye at the rattle of a teacup next to his head, pulling the compress away from his face in shock at the milky tea and plate of biscuits sitting on the table in front of him. Sherlock's still standing there, weight awkwardly balanced on one foot.

"Did I get it right?" Sherlock asks, "You always want tea and biscuits when you have to take paracetamol, because it upsets your stomach."

John looks and sees the bottle next to the plate and nods.

"Good," Sherlock says, and hobbles back to his chair, opening his book and carefully thumbing through the pages until he finds what he wants, and picks up a pen.

Well, that was strange, John thinks. He's pretty sure that Sherlock's made tea less than five times in the entirety of their two-year association, and two of those times were because John was too sick to make it himself. Well, he's not going to examine this gift horse too closely. For all he knows it could be a dragon in disguise.

"What have you been writing up all this time?" John asks around a biscuit. "You've never spent so much time at once on that thing. Bored to death, are you?"

"Merely some observations," Sherlock responds, and they spend the rest of the evening in companionable silence.

Sherlock and John really do work well together. Sherlock needs John to help him navigate the vagaries and subtleties of human behavior on occasion, and John needs Sherlock to remind him that he's still young, still fit, still himself. They're more alike, too, than their temperaments would suggest. For instance, they both have low tolerance for bigots, for cruelty and for shame; they have high tolerance for awkwardness, the cold, and the dark. They both like steamed dumplings and argue over them because there are always five in the order, and instead of trying to split the last one, they each try diversion tactics to snatch three before the other notices. In other words, they're comfortable.

John prefers to write in the evening, in the quiet, with no television and no radio to distract him. This is good, because for all of the disturbance he creates just by existing, Sherlock prefers the same for writing up case notes and organizing evidence. They'll sit in silence across from each other at the partner desk in the sitting room, each in their own world, John typing away and Sherlock scribbling and sorting to his heart's content.

Since they both hate being distracted while they're trying to focus, John discovers that simply sliding a hand across the desktop into Sherlock's field of vision is the perfect way to get his attention without being too intrusive or jarring. John will simply hold his hand out and wait, either pecking away with the other hand or reading until he feels gentle fingers against his. Then John will raise his head and look at Sherlock over the top of his laptop, asking him whatever question it was he'd thought of. It works well, this system, and John finds more comfort than he can express in the warm brush of fingertips across his wrist, a signal that he has Sherlock's full attention for the moment.

They're at work again one late Tuesday night when John suddenly notices a pale hand resting patiently next to the right side of his keyboard. That's slightly unusual; Sherlock is so focused he rarely, if ever, uses the system to get John's attention for anything. John tentatively reaches out his hand and lays it gently over Sherlock's, feeling the warmth radiating over Sherlock's cooler skin. Bright blue eyes meet his over his screen.

"Yes?" he says quietly.

"Do you know your resting heart rate?" Sherlock asks. "It may have changed from the paperwork I reviewed from your discharge."

John frowns a little. What on Earth would he need to know that for? "It was 62 from my checkup last month. That accurate enough for you?"

"Yes," Sherlock says, and goes back to writing.

John shrugs and starts rereading his entry, reviewing and picking bits of sentences apart here and there, trying to reconstruct the case as he remembers it.

And if his right hand stays resting comfortably over Sherlock's left one, well, that's his business.

John stands with his hands on his hips amid the chaos of a fairly vigorous search through his room. He's gone through all of the drawers in his bureau, his closet, and the boxes under his bed that hold the miscellaneous keepsakes of 40 years tucked safely inside.

His compass, the small one he used to clip to his pack when he was deployed, is nowhere to be found. And that means one thing.

Sherlock.

John mutters a string of curses and stalks down the stairs to Sherlock's bedroom and throws open the door. Sherlock is a thieving thief who has no sense of personal space, and when he takes something he can't be arsed to put back where he stole it from, John knows where he'll find it: on Sherlock's bureau, in the small hammered brass bowl he nicked from Mycroft's flat some year s ago.

The light in Sherlock's bedroom is dim, filtered through heavy curtains he keeps drawn day and night. John carefully examines the contents of the bowl (he knows never to just stick his hands in – God knows what else could reside there) finds his compass, and fishes it out. When he turns back to the door, he notices that one of the evidence boxes on the Index shelf, the largest one, is askew with the lid half-off.

John approaches warily, interest piqued. He's never seen what Sherlock keeps in the boxes, not wanted to know, really, since the incident with Oppenheimer's scalp. But Sherlock's not home and it's not like Sherlock's never snooped in his things before, so it's with no guilt whatsoever that John lifts the largest box onto Sherlock's bed. He throws open the curtains for a bit better light and takes a look inside.

His throat closes up and his stomach twists with what he sees. The box is filled half-way with all sorts of things, but what arrests John's attention is that they're all his.

The wristwatch his mum gave him on his 21st birthday, smashed from a fall during a chase across the West End that ended up cornering a forger against the back garden fence of a house for over an hour, until Sherlock's relentless (and annoying) questioning drove the man to give up. A torn white t-shirt, blackened and smudged with dust and ash from an explosion in a swimming pool. John closes his eyes and wonders if he could smell the chlorine if he opens the plastic evidence bag. A single shell casing from the first night he saved Sherlock's life.

John thought he'd lost the casing, the only tangible evidence of what he'd done. He thought it might have fallen out of his pocket sometime between shedding his jeans on the floor of the bathroom while he sluiced the grime and the entire unbelievable night from his body under the hot spray of the shower and the next morning when he got dressed and went to gather the rest of his things from his bedsit. He wondered if it had rolled into an obscure corner somewhere under the furniture, but he was always confident the casing was in the flat. And here it is.

Each box has a number that corresponds to an entry in Sherlock's Index, which means this box should have an entry as well. John pulls the Index from the shelf and gingerly places it on the bed. He opens it toward the end, paging through until he gets to the "W" section.

The first page under the heading "John Hamish Watson" is covered in Sherlock's flowing script; notes for everything from his birthday to his height and weight, the fact that he wears size 8 shoes and is allergic to shellfish. An entry for his blood type, complete with a small square of white paper toweling spotted with blood in a plastic bag attached next to the notation. There's a drawing of the scar on his shoulder, a small pen sketch. He doesn't remember Sherlock ever seeing his scar, at least not close up.

The next page is almost worse, and John shakes his head and clenches his teeth at the "Sexuality: generally bisexual. Currently leaning toward females" and "Last long-term relationship with fellow student Colleen; ended when joined RAMC." These are things John's told Sherlock in confidence, things mates share over late night takeaway watching telly and teasing each other about how bad the other's taste in partners is. John feels hurt and betrayed that Sherlock would treat that information so cavalierly, as if it were nothing but data to process.

The more he reads the more upset he becomes. A tiny evidence bag containing what John is pretty sure is his own hair has the notation "Dishwater blonde. Receives haircut every six weeks." Another small bag looks like it contains fingernails. Underneath both is an honest-to-God, police quality fingerprint. Good Christ.

It suddenly dawns on John what's going on. Sherlock's building a damn evidence locker for him in case all anyone ever finds are bits of his body. Which is something more likely to happen these days than at any other time in his life.

At least, he thinks that's what Sherlock's doing until he turns to the third page.

"Shoulder pain in less than 7 degrees if damp. Less than 5 degrees if dry."

"Paracetamol causes nausea if taken on an empty stomach. Ensure tea and biscuits available."

"Prefers quiet to write in blog."

"Generally prefers Angelo's to Iarea's, although prefers Iarea's minestrone."

"Does not like palek paneer."

"Likes television with breakfast."

"Possesses softness and delicacy of touch."

"Finds my deductions fascinating, and does not begrudge me my abilities."

"Is incredibly resourceful when outnumbered."

"Resting heart rate 62 bpm at April examination."

"Finds me attractive but will not act on it. Curious. Will wait."

John snaps the Index closed, a tiny fluttering of possibility burning low behind simmering frustration.

The downstairs door slams and John hears Sherlock calling out to Mrs. Hudson. He knows full well he'll never be able to put everything away in time to escape detection, so he snatches his broken watch out of the box and heads out to the sitting room, preparing himself for what is sure to be a painful conversation.

"Evening," Sherlock says, dropping a stack of files on the couch. "Thought you could help me sort…what's wrong?"

"I found this," John starts, holding out his watch for Sherlock's inspection.

Sherlock doesn't even flinch, simply nods. "Yes, I kept it when the hospital took it off to fix your wrist. You never asked for it back; I assumed you no longer wanted it."

"Well, I did want it. I thought it was lost. But the bigger question is why did I find it in a box with a whole lot of other things that, at one time, were mine?"

Sherlock looks at him like he's stupid. "That's all evidence," he says, as if he's explaining something to a very small child.

"No, Sherlock, it's not 'evidence.' It's my things. And you have them. Along with a lot of other weird items, I might add."

"Such as?"

"Such as blood samples! Fingerprints! Good god, do you have a DNA workup on me?" John sits down the armchair and puts his hand over his face. Jesus. Next he'll be cloned, he knows it.

"I fail to see what's bothering you," Sherlock says, standing in front of his chair. "Of course I have all of these things. I keep information regarding people in my Index. Why does this surprise you?"

Leave it to Sherlock to miss the point of the thing. "Because, dammit, I'm not just a random piece of data to be cataloged in your bloody book!" John bursts out, slamming his fist on the arm of the chair.

Sherlock takes a step back, slightly wary. "I never thought you were," he says. "It's everything I know about you. I want to keep it, so I remember. It's important, do you see?" His voice is slightly pleading toward the end, and he crouches down next to John's chair so they're level.

"Sherlock, you wrote things – things about me, that I wouldn't tell just anyone," John whispers. "I told you because you're my friend."

Sherlock scrubs his hands through his hair. "But you know things about me. You know about Victor, and about Lestrade and the drugs. You even remember I hate mushrooms! Why is this any different?"

"Because," John starts, because I didn't write it down. Because everything I know about you - your hatred of mushrooms, your strange ability to eat sweets at any time of the day or night, how you like your tea and the feel of your hand against mine - is kept here, in my head. In my heart.

"Because what?" Sherlock snaps. "Because you don't keep notes? I beg to differ."

John almost protests until he remembers an argument that sounds remarkably like this almost two years previous, Sherlock nastily quoting his own words back at him: 'Sherlock sees through everything and everyone in minutes. What's remarkable is how spectacularly ignorant he is of some things.' John winces at the realization – while Sherlock has been collecting and learning and writing things down about John, John's been doing almost the same thing. Getting to know Sherlock, learning about him. Understanding him. And writing a good chunk of it down – in his blog.

John suddenly feels about six inches tall. His anger evaporates and he feels sheepish. "I'm sorry," he says finally. "You're right. We are sort of cataloging each other, aren't we? Well, your cataloging isn't quite the same as other people's, really, but it's not like much else of you is, either."

"God save me from the ordinary and mundane," Sherlock says. His temper has quieted, burning down as quickly as it flared up. He quirks a half-smile, showing John he's forgiven.

John shifts in his chair. "I understand it, but I suppose I never thought anything about me would be interesting enough to merit that kind of effort."

Sherlock settles on the floor, cross-legged and thoughtful. "I can't imagine not doing it, especially for you," he says quietly. "It's everything I've learned. There isn't anything I don't want to know."

John starts a bit at the tone of Sherlock's words. His eyes are bright, hopeful, eager, and John wonders a bit about what Sherlock is waiting for. What he himself is waiting for.

There are moments in life when opportunities present themselves, wave flags and shoot fireworks for your attention. John's never been the sort of man who allows life's chances to pass him by untried; no, he's been aware of the tension in the flat ratcheting up over the last month, and Sherlock's words in his Index are like kerosene on a smoldering fire.

"Anything?" John says carefully, "Because anything can cover a pretty wide selection of things."

Sherlock grins. "I said anything and I meant it. Why? Have you something new?"

John slides from the chair and onto his knees in front of Sherlock's crossed legs. Sherlock gives John an amused, puzzled look as he leans in slightly.

"I saw what you'd written," John says. "I thought perhaps I could satisfy your curiosity a bit."

"About what?" Sherlock says, quirking an eyebrow. He looks interested, intrigued, and John's heart starts hammering.

He scoots a little closer and places both hands on Sherlock's knees, giving him leverage to lean closer still, until he can feel Sherlock's breath on his face. "About why I wasn't acting on it."

Sherlock's eyelids droop slightly as he looks at John's mouth. "Yes," he whispers. "I do wonder why."

"Because I was waiting for the right time," John says, and closes the distance between them. "And I think now is just about perfect."

He captures Sherlock's mouth in a soft kiss, moving gently, sucking on Sherlock's full lower lip until he gasps and winds a long arm around John's back, tugging until John has to climb into his lap or risk knocking them both over. John goes willingly, pushing Sherlock's bony knees out of the way. He wraps his hands around the back of Sherlock's head and pushes his fingers into the soft curls at the nape of his neck, angling his mouth to kiss more deeply, more slowly. With more intent.

Sherlock groans and slides his hands up the back of John's shirt, stroking his skin from shoulders to waist, until his attention is captured by John's scar. He can feel Sherlock's curious fingers tracing it, learning it, even though they're still kissing, tasting each other. John almost rolls his eyes at Sherlock's multitasking, even as he becomes more and more distracted himself by the feeling of Sherlock's tongue sliding against his. The feeling is heady; John's giddy with it, and as he pulls back to grin at Sherlock he's sure he must look completely ridiculous. Here he is, almost 40, sitting in Sherlock's lap and having what he's pretty sure is the best snog of his life.

Sherlock grins back, a predatory gleam of teeth and eyes before he ducks his head to attack John's neck, pushing his collar out of the way to kiss and suck at the tendon between John's neck and shoulder.

"Sherl – stop! Stop, it ticklesooohhh God," is as far as John gets. He's caught between gasping at the talented swirl of Sherlock's tongue against his skin and laughing at the tickling rasp of stubble along his throat. He can feel Sherlock hard and thick under his thigh, and if he has his way, they'd be better off getting to the bedroom. Quickly.

John pushes back, detaching Sherlock from what he's sure is a massive purple mark that was just left on his neck, and scrambles inelegantly to his feet. He holds out a hand in invitation.

Sherlock blushes – blushes, John can't believe it, that's something to remember – and takes John's hand to pull himself up.

"I'm sure there are quite a few things we can do and put in that book of yours," John says, sliding his hand around Sherlock's hip.

"Mmmm. And I think I'm missing one very important sample," Sherlock muses, seeming to get lost in contemplation.

John snorts a laugh. "I didn't realize you could be that crude."

"I can be absolutely filthy, too. Want to see?"

John smiles and kisses Sherlock on the jaw. "More than anything."

Title from "A Scandal in Bohemia."

Notes: "For many years he had adopted a system of docketing all paragraphs concerning men and things, so that itwas difficult to name a subject or a person on which he could notat once furnish information."