When you're a kid, you have this whole different notion of the world around you, and it's built mostly on innocence, naivety and a lack of general experience in life. The result is a whole bunch of 'firsts', not all remembered at an older age. This notion is gradually lost as time goes by, which often causes childhood memories to become sort of a blur, although there're always those few moments that stick in the back of your head and accompany you for life.
Sherlock's childhood was a very privileged one in some aspects - living in a castle and receiving the best of education isn't something people tend to complain about - but it also lacked things that no kid should ever have to grow up without. One of those things was a mother.
Now, Sherlock has always had the most remarkable memory, but not even he would be able to remember a woman who was only with him for his first few days. Violet Holmes had went terribly ill shortly after the birth of her second son, and died when Sherlock was merely two weeks old. Yes, he still had a father, who loved him very much; he just forgot to show it every once in a while. After his wife's passing, the king had become bitter, and that was the only version of him that Sherlock had ever known - only Mycroft had had the privilege to hold on to the memory of a more loving father and their dear mother.
One of the few occasions Mr Holmes ever showed the slightest trace of affection towards either of their sons was when he came back from a long trip (which happened quite often), and came into Sherlock's room when he was deep asleep, placing a tired kiss on the boy's forehead. Except he wasn't always deep asleep. What his father didn't know was that he regularly stayed up way past his bedtime to make experiments with whatever he could find in the kitchen and in the garden, to read books that would make any other kid his age die of boredom, or to practice the violin inconveniently loud. And Sherlock often took the opportunity to do these things when his father was away, rushing back to bed whenever he heard footsteps.
His father's kisses were one of Sherlock's first memories, and he remembers the tiniest details. The sound of footsteps, as silent as the chubby old man could manage, against the marble floor. The scents of his many different perfumes, each one memorized by smell, name, and frequency of use. The ever-changing length of his beard, through which young Sherlock could often deduce his father's current emotional state.
But apart from those precious moments, Mr Holmes was a man who strongly believed that discipline was the single most important thing when it came to raising his children. Sherlock, when growing up, was much closer to his older brother than to their father, although they would eventually drift apart in adult life. Mycroft was the one who introduced him to John, and even though he never said it, Sherlock was most thankful for that.
The thing with the Watson family was that, many years before Sherlock was born, almost every royal family from the neighboring kingdoms had signed a peace agreement among each other that included providing shelter and lodging to whoever had come upon any complications that precluded them from staying in their own kingdom. In the case of the Watsons, that complication was a massive riot that had turned into a revolution, eventually resulting in the entire castle being set on fire. The Holmes family was the one that lived the closest from them, and probably the only ones with a castle big enough to house the enormous Watson lineage and their hundreds of servants.
There were many kids - John had four brothers, three sisters and countless cousins - and Sherlock did his best to avoid them. He woke up every morning wishing that the king of the intruders would solve whatever problem they had that was stopping them from going back to where they came from, so they could leave him and his family alone, in peace and quiet. But he stopped thinking like that in one cold rainy morning, when laziness was heavy in the air, specially in both Sherlock and Mycroft's favorite room: a small and cozy reading lounge, with dozens of books and the best fireplace in the whole castle. This private library of theirs was quite hidden away, so they were hardly ever disturbed, and that's what they liked: isolation. Well, most of the times, at least.
Every once in a while, Mycroft would open the window and let in an old friend, that eventually became a bit more than a friend. Even though Sherlock was only ten at the time (seven years younger than his brother), he knew better than to say anything to their father. And Mycroft was quite aware of that; he had never asked him to keep it a secret and he knew he didn't have to. Sherlock did come to use the information to blackmail his brother once or twice, but it was nothing but a threat - he could never have brought himself to actually do it. It had all started when Sir Gregory Lestrade came to the castle to deliver a message from the army, and was instructed to go to that little library to find the elder prince, since the king was away. He was invited in for tea and, before you notice, he was carefully calculating the days the king wouldn't be home so that, whenever he came to report, he would have to go find the prince. It took ages before any of them actually made a move, considering that a knight could never have a future with a king, but ever since it happened, his visits had become more frequent and more secret.
And in that lazy morning, Mycroft opened the window to greet a particularly soaked Greg with a kiss on the lips.
"It's raining like hell out there." the redhead rebuked him after closing the window, and rushed to cover the freezing knight (who wasn't currently in shiny armor) with a blanket. "You didn't have to come."
"Well, I wanted to come." the other teased, gratefully accepting the blanket and sitting on his usual armchair, placed next to Mycroft's. "And how are you doing, kid? Have you solved the mystery of the missing cat already?"
"Oh yes, in a heartbeat." he replied, without looking away from the book in his hands.
"And?"
"I wouldn't eat the beef tonight if I were you."
"Lovely."
So the crown prince and the knight got a couple of books for themselves, and they each sat on their separate chairs, reading and casually holding hands as they did so. After a couple of hours of the coziest combination of silence, the sound of rain and the crackling noises that came from the fireplace, there was a knock on the door.
"Wonderful" Mycroft grumbled, standing up. "Nowhere is safe."
He answered the door and closed it behind him, taking care that Greg would not be seen. He came back less than a minute later.
"Apparently, my father wishes to speak to me." he said to no one in particular, then turned to Greg. "I'm sorry, but god knows how long that will take; you should probably go."
"No, but- there's something I have to talk to you about first."
"Why didn't you tell me when you got here?"
"I think... I wanted to postpone it for as long as I could."
Mycroft's eyebrows turned to a frown as he told Sherlock to go read outside, without taking his eyes off of Greg's.
"But I'm still picking my next book."
"Then pick fast" he snarled between his teeth.
"You can't just rush into these things, I am about to dedicate hours of my attention to a certain topic, and i expect it to..."
But Mycroft took his brother by his arm and led him out of the room, stumbling into John in the hallway. Before anyone could apologize, Mycroft pushed Sherlock towards the confused prince. "See? Someone your age. You're one of the Watson kids, aren't you? The youngest. You two even have something in common to discuss; neither of you is ever going to ascend to the throne. How does that feel?" There was no answer, and the two children just exchanged a few astonished glances, trying to figure out the situation.
"Well, then? Go... socialize." he said, doing a subtle "shoo" movement with his hands, before returning to the library and closing the door, leaving a socially awkward Sherlock and a confused John alone in the hallway.
After a few more moments of uncomfortable silence, Sherlock straightened his clothes and turned to John.
"I apologize for my brother; he can be rather brute at times. Although I'm afraid I have no intention of engaging in a conversation with you."
John stared at him for a moment before replying. "You talk weird." And he narrowed his eyes, getting closer to Sherlock's face, as if to examine him. "You know, like the grown ups."
The pitch haired prince blinked a few times in confusion, wondering if every other kid was like that.
"I'm John." he smiled, extending his hand. Sherlock politely shook it, but he didn't get a chance to respond. The blonde came closer to him again, and whispered: "Do you know where the dungeons are?"
"Dungeons?"
"Yes, doesn't this castle have them? In our old castle, we had a whole lot of secret entries and dark stairways that led to a bunch of empty cells and torture chambers, unused for decades! You know, before it was all burnt to the ground. It was my favorite thing to do back at home, and I've been looking for passages ever since I got here!"
"Hmm." Sherlock was suddenly interested. He had just read a book the previous week about the structures of castles, that had an entire chapter dedicated to rooms and underground halls that were kept in secret. He had been meaning to go look for them one day, and what harm could come from doing it with someone who already had some experience in the matter? "I suppose I could help you." he announced, and started walking through the long hallways, headed to the stairs that led to the ground floor. John quickly caught up with him, following him around.
"So you know where it is?"
"No, but i believe i can find it."
"But this castle is huge! Have you always lived here?"
"Is the talking thing really necessary?"
"Alright, alright, I'll shut up."
And he did. For about twenty seconds.
"What if we get caught?"
And Sherlock just rolled his eyes, letting John talk to himself as he tried to focus and remember anything he had ever seen that could have seemed suspicious, that could lead them anywhere. If there was a hidden entrance, it would be somewhere no one ever goes, and no one ever questions. He suddenly stopped walking.
"Yes, of course", he muttered.
"What? Do you know where it is?"
"Isn't it obvious?"
"..."
"The trophy room, John! Who ever goes to the trophy room? No one, it's always empty! And nobody ever questions it, why would they? The only people who would go there would be the servants, to do the dusting, but if the king is the only one who knows about the location of the dungeon, he could easily tell them to leave the room alone and say it's for sentimental reasons. It wouldn't be in any of the guest rooms, because they're all being used by your family, and this way, he doesn't have to hide an entire room. Because trust me, I've been up and down this castle for years, and I would know if there was an extra room in any of the visible stories. If there is a secret passage that leads to an underground floor with mysterious dungeons, than it's got to be there!"
And he scampered off, with John right behind him. The trophy room wasn't one of the big halls held by the castle, but it was still pretty majestic, something like their private little museum. Enormous paintings decorated almost every inch of the walls, and sculptures stood scattered across the floor or were hung from the ceiling. Everything there was quite tall, so it could seem a bit like a labyrinth for a couple of children.
"Well" John announced, "we better get started then. You're the smart one. What are we looking for?"
"Any irregularity in the walls or on the floor. Move things around if you have to, but be careful."
So they spent the next half hour checking everything they saw; a crack on the wall, a rip on the carpet, a crooked marble bust. Then Sherlock found something on the baseboard of the wall, next to a real size soldier sculpture, and called John.
"Where is it?" the blonde asked, kneeling next to Sherlock.
"There." he pointed.
"I don't see anything."
"You do see, but you don't observe." he said, and waited for John to realize what was different. "Oh, goodness, is everyone else that slow? Look at the dust pattern here... and here. This layer is thinner, see? It means someone recently touched it."
"But... If that really is the entrance to the dungeon... Does that mean that someone's been using it? Could there be prisoners down there?"
"Let's find out." And Sherlock pushed the wall - a three foot tall square of bricks began to roughly slid backwards, and John helped him push it till the end. A dark stairway was revealed, and the two kids smiled at each other in triumph.
"All we need now is some light" John advised, already climbing a marble pedestal to reach the torch that rested in a sconce on the wall.
"Careful! You'll break something!"
But John landed gracefully on his feet, holding the lit torch.
"See? I'm not as useless as you think."
"I don't..."
"Yeah you do. But I bet you're nice, deep down. Come on." he called, already with a foot on the first stair, but he turned to face Sherlock again. "I never got your..."
"The name is Sherlock Holmes."
