A/N: This is the revised version of the first part - there aren't many changes, but it needed a spot of betaing. I'm currently working on the second part. Many thanks to those who commented and favved so far.

Planned before/not compliant with S2.

Wise Child

It is a wise child that knows its own father.

English proverb

All in all (to quote Dr Watson's profound observation in a blog entry that never saw the light of day) it really came down to poetic justice. Sherlock was a little too fond of telling Detective Inspector Lestrade that the latter wouldn't spot his own two feet in size-twelve Dr Martens and red mountaineering socks. The Fates must have tired of the joke, or they wouldn't have tipped Sherlock into a midnight bath that left him flapping and fretting at his nemesis' escape while Lestrade tried his best to keep his consultant inside a blanket.

He was threatening to radio for backup and hot Ribena when the blanket slipped one more time over Sherlock's deceptively bird-boned frame. The flashing light on the nearest police car caught a dark smudge on his left shoulder blade, and Lestrade blinked.

Then whipped off the blanket altogether, leant forward for a closer look, and said, "Bugger".

Sherlock stiffened at the word. "If that," he replied sternly, "is your monthly contribution to deduction, I'm not impressed. Even John beat you to it on our first meal, and –"

"No, you fool! The mark! The biggish, blueish whatchamacalit – have you always had it?"

"Oh, that." Sherlock, ever the Contrary Mary, had grabbed the blanket and was pulling it back while Lestrade held stubbornly to the other end. A brief tug-of-war ensued as Sherlock carried on. "That, Inspector, is commonly known as a birthmark. Don't tell me you've never come across one in your trade? Mycroft used to call it the Blue Carbuncle, but then Mycroft's wit would hardly fill one of his tooth cavities. Makes it such a bother to investigate Turkish baths undercover. And gyms. And the Neo-pagan hikers. Lestrade, what are you doing? I couldn't be less interested in your ankle, man, and now is not the time for a crime scene reconstruct –"

But Sherlock had to freeze mid-diphthong. Lestrade's left foot, now he'd pulled off his shoe and sock, sported the exact same mark – biggish, blueish, dimly spiderish – on the instep. The two men looked up at each other slowly. Lestrade's expression was that of a fawn staring at a refrigeration van's headlights. Sherlock's expression was that of the fawn having successfully pegged the van as the same vehicle that had run over his mother a month earlier.

"Impossible." Sherlock swallowed. "That is, at the very least, very improbable."

"I'll say! For one thing, I have deep brown eyes –"

Sherlock shook his head sadly. "Check your Mendelian tables, Gregor. And look better. There's always something... Ha! Nailed it. You were twenty-two when I was conceived, and unless I'm mistaken, which I'm not, my parents were still posted abroad."

"Thank god." Lestrade clutched at the tendril of hope with wild-eyed optimism. "Where abroad? You name it. Beijing? Paris? Afghanistan?" Where had young Greg been twenty-five years ago, a penny freshly minted by the Met? The past had been a closed case to him ever since the wretched divorce. Ah yes, that exchange programme with – oh god. The Ecole de Gendarmerie at Geneva. Where his libido had been anything but neutral in its heyday. He knew Sherlock had seen him flinch, seen his face blanch as the memory struck home, leaving him no choice but to speak out. In for a penny...

"Switzerland," Lestrade said dully, wondering if this was the moment to remind Sherlock that, as chromosomes went, he'd got the best of a bad lot. Hell, it could have been worse. Could have been Gregson, if he hadn't been grounded at Hendon for shagging the Collision Investigation instructor. "Now look on the bright side, kid –"

Sherlock whimpered.

"Really, brother. I'm surprised." An umbrella tip speared the ground between them, missing Lestrade's naked foot by an inch or two. He hopped back, looking for his sock. "Notwithstanding your little monograph on footsteps, this one eluded you longer than I thought." Mycroft Holmes turned to Lestrade. "My mother's word was good enough for me, Detective Inspector. But I dare say you'll want a test. It seems that diplomatic life in Geneva proved a lit-tle boring at times – no doubt you provided a healthier distraction than milk chocolate."

"I –" Lestrade looked up to see his entire force task convening around them. He could spot Donovan close behind Mycroft, staring at him as if he was the Antichrist. Wonderful. And Anderson was blabbing into his phone, probably denouncing him for five years' stealthy nepotism. Lestrade licked his lips. In for a penny, in for a pounding? "Just what d'you think you're playing at? Why didn't you tell me before you more or less blackmailed me into hiring him?"

"Come, come, Inspector. All I said was, 'That boy needs a firm hand and a smoke detector.' You proved equally reliable in both roles – the blood instinct, I'll wager."

"What did he tell you?" Lestrade asked Sherlock. He picked up the blanket which had once more flopped to the ground, covering the younger man's shoulders mechanically.

Sherlock's voice sounded as if it was filtered through a nutmeg grinder. "That you were quite the average bobby, not worth my time or attention. And that he'd be happy to employ me in a minor capacity if I were to put my intellect to good use."

"Like father, like son. So predictable," Mycroft purred, and Lestrade shoved his balled fists deeper into his coat pockets, taking deep breaths to calm himself. You never knew, governmenticide was still punishable by the axe. Or was it chemical castration in these enlightened days? He'd have to ask the Westminster Division.

"Inspector, if you'd be so kind as to donate a hair... Or a toenail, since they're available. My staff is waiting."

Lestrade lifted his left foot. John Watson, who had somehow made it to the happy crowd, stepped forward.

"Sherlock –"

"I'm in shock," Sherlock said, falling back a pace.

"It's all right. No, it's not. Is it? Oh, Christ. I'd better see you tomorrow, then... er..."

"Lestrade." Sherlock's effort to sound desultory was commendable, but his white face and shaky voice retained a trace of the van-deducing fawn. "That thing that you did – that was – good. Really. Your bouncing hormones made it possible for the Vernet genes to breed in, in, in, in – in a sanitary site, sparing them a stuffier environment." His pointed look grazed Mycroft's figure. "And that's the long and short of it as far as I'm concerned. I don't see any necessity to change what has proved an adequate working relationship. Good night."

He spun on his heel and dived into the crowd, still bare chested. Lestrade felt a hand on his shoulder.

"I'll see to the car, sir." Donovan was looking at him, her countenance now hovering between fleeting compassion and abject hilarity. "I'll make sure the F – that is, your – I'll make sure they get home."

... Lestrade's last thought that night was for the lush lanes of the English Consulate at Geneva and their convenient hedges. And the lush white body rippling under his, wave after wave of blood-tingling lust and Chanel N°. 5, and the voice – his – panting "Oh baby, it's Christmas!" He groaned, pressing his face into the sheets. Charlotte, she had said her name was, and that she was on the pill.

Sherlock was right. His son was right. He was an idiot.

Sherlock, needless to say, did not show up at the Yard the next day. Lestrade did, only to find that he'd been granted a two week paid paternity leave he'd never thought of requesting in the first place. He spent the first hour at his desk, penning a memo to his team and wondering how he could have thought paperwork wearisome before.

Eleven versions were tried and found wanting. The two finalists read as follows :

"To everyone concerned. I guess all of you know by now that Sherlock Holmes, our consulting detective, was found to be my biological son. It's a complex situation, with work-related issues, and naturally you'll want to know what my position is. Here goes. I'll stand by the CO's decision or Sherlock's if they chose to end his consultancy, but my own vote is to give our team dynamics a chance to carry on exactly as they are. Sherlock's skills make him an asset to our work, but you have my word that here and on any professional premises he'll be treated like before and doesn't expect anything else. I've had your vote of confidence till now. I'm asking you to stretch it an extra inch, and trusting no one will rue it."

"To everyone concerned. Yeah, he's my Kinder egg surprise. Take five and laugh your abs off, you tossers, but you'd better have them in tip-top shape when the CO pops in for his monthly tour. And before anyone asks, yeah, still one of the gang, like before – no more, no less. All clear? Good. See you on Monday, then, and on your head be it if any of you calls me Daddy in The Presence."

He tore up the first version, typed the other into his mail box, and got up. He didn't need a week to know what was to be done, but he certainly needed a corpse-stiff Scotch before he did do it and there was no place like home.

"At least have a bite of toast or something." John banged the teapot on the kitchen table to drive his point home. "It's been four days, Sherlock! I don't think anyone, not even you, ever solved a case of identity with a hunger strike."

"What case?" Sherlock, stretched out slantwise on his chair, his slippered feet shoved under the table, was breaking the toast absently over a plate. Apparently, his next masterplan to catch Moriarty implied throttling the man with bread crumbs. That, or he was working on a new fractal theory. "There's no case when there's no doubt. The tests have made it clear that Lestrade and I are genetically connected. Fine. Since he and I and you for that matter are equally connected to everyone else on this planet through six people, I don't see why you're so obsessed with this. You've never inquired about my relatives before when you saw me skip a meal."

John sighed. "Look, it can't be that simple." The table was now spattered with runaway experimental crumbs and he went to fetch a sponge. "Nor for him. You've just found out he's your father –"

"Genitor."

"– and while the two of you have been friends –"

"Colleagues."

" – for years, it's a mind-boggling fact, and you can't pretend it doesn't affect you."

"I'm not affected! Affect is a strictly empirical percept! I don't do empirical!" Sherlock was getting more agitated by the minute, and John pushed his advantage along with the sponge.

"Well, I bet it's affecting Lestrade. Has he called you?"

"No." Sherlock tucked in his chin as he drew a complex spiral on the oilcloth with his fingertip. "Not that I'm expecting him to unless he has a case. Which brings us full circle to –"

The knock on their main door was loud enough to be heard through the flat. As was Lestrade's voice, pat on the rap. "Sherlock? Let me in. I know you're here, I have your coat's testimony. We need to talk – at least I need to talk and you need to interrupt. Open that door, please."

"I'm not changing my name!" Sherlock yelled out from his chair. "It's been highly functional for twenty-five years, and I see no reason – "

John rose with a sigh, leaving the room.

"I'm not asking you to take my bloody name!" Lestrade was yelling back thirty seconds later, stomping into the kitchen. He had two bulging volumes under his arm. "You can call yourself Sinclair Bassington-ffrench for all I care, you great clodpole." He dropped his burden next to the teapot, grabbed a chair, and crossed his arms ominously. "What I care about is this, and no, let me have my say. You've never spoken much of your folks, Sherlock, and what I know of your Mum would peter out before the third line if I tried to report it. But you – you I've known for five years now, and even if I still haven't figured you out and don't hold any hope I ever will, I've cared for you way more than I had any call to. Now that I know – well. If you're my son, then you're my son, and no one, not you, not anyone, will make me deny it. I'm not gonna force you into some sort of setup, whatever your brother has in mind, I get it that this has come upon you like a sore boil – "

"It's –" Sherlock had winced at his choice of words. "It's not something I'm going to delete. It's just – Lestrade, I've no idea what you expect me to do or say." His voice had gone oddly thin on the last words and John, from his station at the kitchen window, felt a soft pinch in the region of his heart.

"It's all right," Lestrade repeated, his voice gentler. He reached out and brushed the curve of Sherlock's shoulder, careful not to squeeze it. "It is, really. We'll just – make it up as we go, okay? I know I want to." He glanced at Sherlock's averted face, and John could almost hear the click as more pieces fell into place in their two minds. "I guess he – your other father – was not a very demonstrative man?"

Sherlock nodded, eyes on the crumbs. The unspoken words remained unspoken.

"It's all right," Lestrade said again, and stood up. "Look, I can't stay, I'm already late for work. I've really come to bring you these." He motioned to the two enormous scrapbooks on the table. "It's the best I could do. Photographs, papers... you know. Thought you might like to know where you come from. So to speak."

He was straightening his back as he spoke, and John felt a twinge of déjà vu at the defensive pose. "I'm not gonna tell you my people were the pick of England, Sherlock. But they're nothing to be ashamed of. Your grandfather won thirty-four crosswords puzzle competitions in the Times, used to send them under a different name every month. And my Ma was as sharp-eyed as they make 'em. One glance at your shoes, back from school, and she could tell soil from silt and marl from clay, there was no hiding from her if you'd gone and played truant. Hm, yeah, well, there was a hiding, but a light-handed one, really. And then a hug and a hot muffin, and everything forgotten until next time."

The West Country burr was gathering in his voice, and Sherlock lifted his head, intrigued. Lestrade's smile had taken ten years off his face.

"Anyway. Keep them as long as you like. And – well, you know where to find me." Lestrade had made for the door. He was halfway into their living room when he snapped his fingers, stepped back, looped an arm round Sherlock's still frame, and pulled him to his chest in a solid hug.

Sherlock went rigid with horror. At the window, John Watson turned quickly aside and yielded to a fit of impromptu asthma.

"Yeah, forgot to tell you. The Vernets don't have a monopoly on Continental genes, son. You're the happy owner of a pint or two of Gallic blood – Southern Gallic blood. Bye, John."

John waited till the flat door had shut with a boom to turn back. His flatmate was unhitching himself from his chair with a poker face which, in John's experience of gambling which extended over many nations and three continents, wouldn't have fooled a charity bingo novice.

"Er, d'you want to take these to your room?" he asked, pointing to the albums. He did not expect an answer and got none. Knowing from experience that a kitchen table had little to no chance of remaining a tabula rasa in Sherlock's proximity, he carried the scrapbooks to their living room and cleared a niche for them on one of the lower shelves.

Then busied himself a little more with them before going up to his room. Sherlock was not the only one who liked to run experiments after all, and John had learnt a thing or two, living with a man who constantly paid of his own person for science.

The rest of the week dribbled on.

A comment appeared on Sherlock's Web site which might or might not have come from Moriarty, though Reaching back to you very very soon, dahling! hardly smacked of the Master at his best. Sherlock turned to the Internet and checked dahlias, dalits and little dahus, not putting any real effort into the chase. Most of the time he huddled on his long-suffering sofa and watched the sun rise and the sun set, and the British rain fall on the nothing new.

John was no help at all. John's answer to Sherlock's mention of the nothing new was, "Please tell me you're joking," and "Have you called him yet? " Calling Lestrade, according to John, seemed to entail making animated chit-chat about being Lestrade's son. Which was problematic.

Once the first shock of had worn off, Sherlock had found that he liked his new status. It made sense, in a way that pleased his mind more than he'd thought possible. Lestrade had always been there for him in his solid, stubborn warmth, and Sherlock knew it; knew that without the DI's rough blessing, even if it came with drugs busts and spastic index fingers and inept questions, he would still be an embryo in the great womb of detection. Without Lestrade, he would have remained "Holmes, S." on a students' registration list instead of becoming SHERLOCK HOLMES on two celebrated Web sites. Names were immaterial. Facts mattered. Sherlock looked at this particular fact, and Sherlock saw that it was good.

But, dear Lord, what else was there to say? He'd Googled "sonhood", letting himself be momentarily sidetracked by the Scrabble forums, then restricted his search to "unexpected paternal recognition". And he still didn't see his way to sustaining even a five-minute exchange on the topic, unless Lestrade showed interest in the late President Mitterrand or, perish the thought, Star Wars. So he'd dipped into Lestrade's albums, taking the blond eyelash planted between the eleventh and twelfth page and putting it fondly in his shirt pocket. It would have been easy to set it back in place, but if it pleased John to find out that he'd consulted the books, Sherlock was willing to overlook a stratagem inspired by John's calamitous detective novels.

Besides, there might be another family mystery to plumb. He'd looked up statistics on the comparative rate of illegitimate births in rural and urban environments and the results were quite encouraging.

On Friday night, while John was cooking what he would inevitably call the Trooper's Risotto, i.e. beans and ham, and Sherlock was completing a new tour of the albums, Lestrade called. Sherlock pounced on his phone.

"Sherlock." The DI's voice sounded cautious but resolute. "Thought you might like to help with a case. Circus owner found dead, mauled by a lion, him and his missus too. Some foul play by the look of it, but no one saw anything, the lion's cage was locked from the inside and the lion himself can't be found. Also, there might be a Doomsday sect involved. Do you want...?"

"Yes," Sherlock breathed happily.

"Good. Take a cab to Hampstead and ask for Rounder's Show. And, Sherlock, I'd rather you brought John. And – "

"Yes?" Sherlock asked, mouthing "lion" and "cab" to John almost simultaneously.

Lestrade seemed to hesitate, then said, "Look, just remember – no, never mind. See you there."

Sherlock waited, but all he heard was a tinny ringing tone. As he hurried out onto the landing, coat and John in tow, he nearly collided with Mrs Hudson carrying a covered plate.

"Oops! Careful, dear. Going a-roving, are we? Your detective inspector must have called. Say hello from me, will you, he's such a lovely man. God knows that if I was ten years younger – "

She was cut short by a firm peck on the cheek. Sherlock was looking at her with the beaming countenance that she alone seemed to call up in him.

"It's all right, Mrs Hudson. You'd still be past procreating age, but I've always considered you more or less in loco parentis."

And left her gaping after him as he skipped down the stairs, John's exasperated sigh unheeded at his back.

TBC