Author's Note: This is the next installment of my kidlock fic series ("Inception," "Marooned," and "A Study in Pink Nail Polish"), in which John and Sherlock meet as children. You don't really need to have read the previous installments to understand this one, though it would probably have more impact that way. I was actually intending to include this explanation of Sherlock's scarf in "A Study in Pink Nail Polish," but it just didn't seem to fit, so in the end I came up with this idea instead. This fic includes my own personal headcanon (cobbled together from a couple very sharp fans who put two and two together far better than I could have) of what Sherlock's family life must have been as a child. Obviously, things are a bit different when you throw John into the mix, but I think this is basically how it would work out. Also...I just couldn't resist throwing in a case for Sherlock to puzzle over.

"You can imagine the Christmas dinners."

"Yes- No! God, no."

- from "A Study in Pink"

Even someone as ordinary as John Watson could deduce that Sherlock Holmes was rich. That was safe to assume about half the students in their school, just from the nature of the surrounding neighborhood, but it was obvious that Sherlock was especially well off. Everything said so, from his tailored clothes to his mobile phone to his personal car and driver.

Still, the wealth of the Holmes family never completely dawned on John until he went home with Sherlock for Christmas Eve dinner. He stood gawping on the gravel path winding its way to the Holmeses' house...mansion...castle...whatever it was supposed to be. It looked like it ought to be a museum – or a set out of one of those BBC things his mother watched. Pride and Prejudice and Bleak House and things like that. Not the sort of place real people lived in today.

Of course, Sherlock just strode up the path as though nothing was out of the ordinary, as though he did this every day – but then, he did. John scurried to catch up with him, and tried not to stare too much as they stepped into the entrance hall, which was actually lined with suits of armor. Everything was gleaming mahogany and thick Persian rugs, and John felt very small and dirty amongst all this finery.

Sherlock swirled his coat off with a flourish and headed for the stairs that curved elegantly to the second floor, but stopped short when a voice rang out from a door to the right. "Aren't you going to introduce your...friend?"

John turned to see a rather portly teenager dressed up in a three-piece suit, his hair parted neatly down the middle. There was something about his face that looked familiar, but John couldn't quite place it.

Sherlock spun on his heel and gave a false, sardonic smile. "Hello there, brother dearest. The diet's treating you well, I see – you can actually fit through the front door now!" He turned to John with the same false smile. "My brother, Mycroft – Mycroft, this is my friend, John Watson."

"How do you do?" John said politely, holding out his hand and trying desperately to make up for how horribly rude Sherlock had just been.

Mycroft shook his hand with a smile that didn't reach his eyes. That was what looked familiar – he had the same intense, keenly calculating eyes as his younger brother. "There's no need to keep up appearances, John," Mycroft said in a long-suffering tone. "I know he just brought you here to make a point, so feel free to leave whenever you see fit. Sherlock," he added immediately, turning back to his brother before John could formulate a response of any kind. "Father just called to say he can't make it."

Sherlock froze. His entire body, which was usually animated and full of restless energy that made it seem like he was pacing the floor even when he was standing still, grew stiff and rigid. All irritation fled his face and he looked blankly, emotionlessly, up at his brother. "What?"

The intent look the brothers shared was full of a hidden meaning that John couldn't even begin to fathom. "He had some urgent business to attend in Brighton. Unavoidably detained."

John didn't know what was going on, but he could practically feel the hot waves of hatred pouring out of Sherlock. His teeth clenched, and then he stormed off up the stairs, stomping as loudly as he could. "Of course!" he snapped, every syllable bursting with venom – though it didn't seem to be directed at Mycroft. "It's been three years already; he can forget about Christmas as long as he has his business to occupy his time!"

A few more stomping footfalls, a slamming door, and Sherlock was gone, leaving John standing bewildered at the foot of the stairs. Mycroft sighed, rolled his eyes, and turned to wander back into the room he'd come from. "Make yourself at home, John..."

"Wait!" John called after him. "What did you mean, Sherlock was just trying to make a point?"

Mycroft turned back with a mysterious little smile. "Most likely you've picked up on this by now, but my little brother is not very...socially adept, shall we say. He's tried several times to bring someone home and prove they're his 'best friend.' But as soon as he thinks he's proven something, he'll lose interest. Please don't take offense if he ignores you after Boxing Day."

"You're wrong..." John said softly as Mycroft wandered off. "He's my friend... He really is..."

Even to him, it sounded like he was making excuses.

After standing in the hallway cluelessly for a minute or two, John tentatively started up the stairs to the second floor. This hadn't exactly been what he'd expected when Sherlock invited him to Christmas dinner, but he'd agreed to come, so he had to make the most of it. At the top of the stairs, he looked both ways down a long, carpeted hallway and wondered whether he should just start opening doors until he found his friend. But as he started wandering down the hallway, his eyes landed on the door down at the very end. It couldn't have been more obviously Sherlock's if it had a little brass nameplate on it. Chemical formulas had been scratched into the wood, creating a tangled mess of white lines. There were signs that someone had tried to smooth the scratches over, but they were too deep to remove.

Cautiously, John knocked on the door.

"Come in, John."

John closed the door behind him and stared around at the room, noticing that the walls were covered with the same scratches as the door. "How did you know it was me?" He took in the beakers, bunsen burner, and microscope littering the desk under the window overlooking the grounds. There were also dozens of cards scattered about the walls and floor, covered with every kind of bug imaginable pinned to them, systematically labeled with their scientific names.

"Mycroft never knocks."

Sherlock himself lay on his back, hanging off the end of his bed with his head dangling upside-down a few inches above the floor. His coat lay in a crumpled heap in the middle of the floor, but he hadn't taken off the long, blue scarf he seemed to wear everywhere. John stuck his hands in his pockets and looked down at Sherlock's face, which was starting to turn purplish-red as all the blood rushed into it. All of his previous rage seemed to have drained out of him; he lay with his eyes closed placidly and his hands pressed against each other as if in prayer.

"Erm...why are you...like that?"

"Helps me to think."

"And what are you thinking about?"

"Carl Powers."

"Who?"

Without looking, Sherlock pointed at a news clipping lying on the ground near John's feet. John picked it up and started to read. "Star athlete drowns before swim meet..."

"He had a fit in the water and drowned before anyone could rescue him," Sherlock explained, still hanging upside-down. "No history of epilepsy."

John looked at the blurry little photo of the dead swimmer, confused. "Did you...know him?"

"No, but something's not right." He flipped over onto his feet, turning to start pacing about the room.

"Careful, the blood will rush-"

Too late. Sherlock fell forward like a board. John scrambled to catch him before his face could smash against the floor, and managed to break his fall a little. Thankfully, the carpet was thick and soft. John grabbed Sherlock's coat and stuffed it under his head, trying to untangle his long, gangly legs so he could lay flat.

His efforts were made especially difficult by Sherlock, who was gasping and groping around desperately as though he were drowning. "John...John, I'm dying! John!"

"Relax," John grunted, recoiling as Sherlock's knuckles knocked against his cheek. "You just fainted. I did warn you..." He hesitated, then tentatively put his hand on Sherlock's scarf. Sherlock's brown curls were plastered to his forehead with sweat, and John knew the knitted scarf couldn't be very comfortable.

Sherlock's hand closed around John's wrist as if out of instinct and their eyes locked. Then, slowly, he let go and John gently pulled the scarf off. After folding it carefully and setting it beside Sherlock's head, he looked down at his friend and waited. There were so many questions he longed to ask, but he knew it was none of his business. He'd learned long ago that there were some things that would just have to stay mysteries with Sherlock Holmes.

But as Sherlock calmed down and his breathing evened out, he stared at the ceiling with a thoughtful frown. "My father has a mistress," he said abruptly. "In Brighton. He claims he goes there for business, but I know the truth."

John blinked in surprise, wondering why Sherlock was suddenly explaining this. Was this just another case of Sherlock wanting to make sure his friend appreciated his deductive reasoning? Or was it something he'd never been able to tell anyone before, something he'd longed to say, but there was no one to tell?

"It went on for years," Sherlock said to the ceiling, his eyes clouded and distant. "Mycroft knew it too, but it was just...something no one ever talked about. Three years ago, at Christmas, we were waiting for my father to come home so we could have dinner. But the hours passed, and...he still didn't show up. So then I told Mother. I told her where he was. Why he wasn't coming back." He turned his head to look at his blue scarf, and fingered the fringe as he said softly, "I thought it would be kinder. No more lies, no more pretense. She wouldn't have to worry about him anymore. But this was the last Christmas present she ever gave me. Mycroft said I was the one who killed her."

"Sherlock..." John didn't know what to say, but there was a painful lump in his throat.

Sherlock grabbed his scarf and pushed himself to a sitting position. "It doesn't matter," he said brusquely. "It's in the past now." He got to his feet, ran a hand through his hair, and crossed over to his desk, where he busily started rearranging the random objects strewn across it to make a work space.

"No, it's not."

Sherlock froze.

John looked up at his friend from where he sat in the middle of the floor. Sherlock looked tall from this perspective, like a grown man bent over his work. He was a child, and yet he'd been asked to shoulder the burdens of an adult. How long until it broke him? "Don't blame yourself," John said softly. "I don't think she would."

Sherlock's fingers closed into a fist around his scarf. He slowly straightened, gazing out the window with an inscrutable expression on his face. John watched him for a long moment, wondering what thoughts were rushing through his head.

"Shoes."

John blinked, then frowned. "Shoes?"

"Yes, Carl Powers' shoes!" Sherlock whirled around with a triumphant expression. "The police found all of his clothes in his locker, but not his shoes! I think we're onto something!"

John wondered if Sherlock had even listened to a word he'd said. But then he saw how animated Sherlock was, how brilliant and energized his smile was, and he knew it was beginning to sink in.

As Sherlock bustled over to the other side of the room to start shuffling through more news clippings, he left his blue scarf behind on the desk.