Chapter Text
It was not raining, as it happens.
This is not an important piece of information to begin with, but it will be.
Sherlock Holmes was returning, as it was, from a particularly unpleasant interview with several rather unpleasant thuggish brutes (who were also unfortunately not involved in the murder investigation).
“Unpleasant?” John snapped, throwing the door shut behind himself. “How can you call that just ‘unpleasant’?”
“I have had worse,” Sherlock responded, holding the handkerchief against his nose. “And it’s not as though it’s actually broken. He was boasting, not actually skilled in anatomy.”
“Yeah, well, I’ll be the one who determines that,” John said, following his companion up the stairs. “And if I think it’s broken, you’re wearing the bloody brace if I have to shove your----“
His words were cut off at the top of the stairs, as Sherlock had stopped, rather prematurely, at the front door. John peered around the taller man, to see him staring at the room’s unexpected occupant. A boy of about four, maybe five, with dark, tightly curled hair. The boy was reading a book and wearing a rain coat and wellies.
Hence the prior comment about how it was, in fact, not raining.
“When did she drop you off?” Sherlock asked.
“About an hour ago,” the boy replied, not looking up from his book. “There is nothing to eat.”
Sherlock turned and looked in the direction of the kitchen, as though suddenly realizing the room was there. “Ah. Yes, I’ll restock it.”
As Sherlock, apparently, had no intention of moving, John squeezed next to his friend. “Sorry, hello,” he addressed the boy. “I’m John---“
“I know,” the boy said. He looked up at this point, and his eyes were rather small for his pudgy face. He reminded John a bit of Mycroft, whenever he gave up dieting for a few months due to stress or irritation. The annoyed expression on the boy’s face also reminded John of Mycroft. It was rather creepy.
The boy gestured to Sherlock. “He talks to you when you are not here. It is really annoying, actually. Mother says I am supposed to expect that.”
John nodded, slowly. “And your Mum is…?”
“A client,” Sherlock responded, choosing this moment to sweep into the room and over to the bookshelf. His bloodied nose apparently forgotten, he tossed the handkerchief on the table and began pulling books, apparently at random, and tossing them onto his chair.
“Did you get me the book I asked for?” the boy asked. He shut the book he was reading. John could see the title; it was a precursory book on mathematics, something John would have expected in someone a few years older than the boy. Nothing terribly unexpected, though. Perhaps the child was just an overachiever.
“It’s up in the room, as you would have noticed if you’d been up there,” Sherlock responded.
“Up in the room?” John asked, blinking. “What, my room?”
Sherlock turned to look at John, and his face was a little tight. It was one of those pointed expressions John never really understood, though he expected that Sherlock put a lot of thought and consideration into that expression.
“It hasn’t been your room in some time, John,” Sherlock responded. He turned back to the bookshelf. “And he does need somewhere to sleep. I assume she gave you the raincoat because she expects to be gone until after Thursday, when we’re expecting rain.”
“Yes,” the boy responded. He looked over to the stairwell towards John’s old room, and his tight, annoyed expression now looked to John as though it were younger, more excited. What sort of a book would an odd child like this want? Something full of racecars and rocketships? No, nothing so mundane, John imagined.
“She just brought you back from Russia, though, I see,” Sherlock added.
The boy sighed, and rolled his eyes.
John’s eyebrows knitted together. “What do you mean?”
“Russian belt,” Sherlock said, gesturing in the boy’s direction. “Newest of his clothes, only bought six to ten days ago, considering the wear on the eyelets. The next newest are your wellingtons, bought in Italy and worn through three rains, so that would be travel by train from Italy to Northern Germany, and then across to Russia. In Germany you also acquired your coat and your sweater, which is too tight on you because it was bought in a hurry. Considering both you and her are aware that it is too tight, it means you have no other luggage, meaning that she’s left in some sort of trouble.”
“Brilliant,” John said.
The boy sighed, and stood, reaching over to the side of the couch, where a small, rolling trolly sat. Luggage? John was astounded.
“She said you’d say that, and I wasn’t to change until you did,” the boy said. He pulled the trolly towards the stairs.
John looked back at Sherlock, whose astonished expression must have mirrored his own.
John licked his lips before he spoke. “Are you babysitting?”
Sherlock sighed. “Under duress.”
He returned to the books on his chair and began organizing them into a pile that seemed completely random to John, but probably had some serious and inventive reasoning behind it that belonged only to Sherlock Holmes. John's mind was still on the boy that he could hear dragging his luggage behind him up the stairs. Someone precocious, it appeared, with Mycroft's coloring and pudginess to his cheeks---did Mycroft have a child that John didn't know about?
As it was, the idea of Mycroft having a romantic life was something that never even remotely occurred to John. The boy was four, so it would have been a woman that John might've had contact with.
"Anthea?" John queried.
Sherlock had moved to the other side of the sitting room, one book in hand, and he looked over at John with pure confusion.
John clarified: "Did Mycroft have an affair with Anthea?" He assumed the 'to produce this boy you're watching over' was implied. "He did take her off of all the impersonal meetings business."
"Absolutely not," Sherlock responded immediately. "She's been secretly in love with Molly Hooper since the first time she saw her on CCTV. Mycroft has her watching Bart's in order to fuel her addiction. I thought that was painfully obvious."
"Nothing is with you," John replied.
There was a shuffling sound, and John turned as the young boy reappeared at the bottom of the stairs, holding a large, brightly colored book titled Orchids. He had changed, as promised, and now wore a simple tee-shirt and jeans that fit him significantly better than the suit had.
"Was it two men, or three?" the boy asked. "Mother says you are a good fighter. One man would not break your nose."
"It's not broken," Sherlock responded.
"It looks broken," the boy responded.
John nodded. "I actually have to agree."
"Do you really have to?" Sherlock grumbled. He put a hand on top of the stack of books. "These are also for you. Finish them up before I get back."
John's eyebrows shot up to his hairline. Books in the stack included a book on bullet manufacturing, advanced criminal psychology, and the Hardy Boys. The boy nodded, clutching his orchid book closer to his chest.
"I'll make sure Mrs. Hudson brings you up tea," Sherlock added. "Come on, John, we've got what we need."
With that, the consulting detective brushed past the child and bolted towards the door.
"Wait, didn't you need to pick something up?" John called ahead.
"Already did! The game is on!"
John started towards the stairs, but stopped in front of the boy. He crouched next to him.
"What's your name?" John asked.
"Arsene H. Lupin," the boy replied, instantly. "It is French. Mother was feeling very patriotic."
"And your mother is French, then?"
"Yes. And was a client here a long time ago."
John laughed at the boy's articulate nature. "How old are you?"
"Five," the boy said. "You ask a lot of questions. Are you a detective as well as a doctor?"
"Did your Mum tell you that? Because I don't remember a Lupin from five years ago."
The boy shook his head. "You said you would set the bone of his nose. I was listening." With that, the boy---Arsene, apparently---stepped over to Sherlock's sitting chair and dropped in, picking up one of the Hardy Boys books and opening it to the first page.
Sherlock's voice called up to him. "Come on, John!"
It was very late when they returned back. Mary had been there to help clean up bandaged knuckles, and had even been "unsurprisingly useful" (as Sherlock put it) by correctly identifying a handgun simply by the recording sound of a gunshot. She also promised to give Sherlock tutoring in determining the sound (the exchange was just a little creepy, the two of them boasting and excited over their mutual gun-sound knowledge. John was, once again, confronted with the possibility that he married a female version of Sherlock Holmes.)
"Yes, well, we'll start again in the morning," Sherlock said.
"It is the morning," Mary retorted. "Three in it, to be precise. If you're tired, you can take a kip in our bed."
"Our bed," John raised his voice from the other room. "Our bed, Mary. You should ask me before you offer it up!"
Mary shook her head and stage-whispered to Sherlock: "He doesn't mind."
Sherlock smiled. He had a lot of smiles, John came to realize. Wide, laughing ones that only really came out when something very funny had occurred, thinking smiles that came out in a case, and those strange, mutually-affectionate smiles he shared with Mary. John often believed that in their minds he was the psychopath and they were the equally-harassed friends. Oh, god. Sherlock and Mary had become John and Mrs. Hudson.
"Actually, I've got to go," Sherlock said. He gestured to the door. "I've got---shopping."
"Seriously?" Mary asked. "In the middle of a case?"
John got to his feet. "Right! Arsene."
Sherlock and Mary's reaction was simultaneous: "Who?"
"The boy you're babysitting. Arsene Lupin," John said. He blinked in Sherlock's direction. "You don't know his name?"
"That's not his name," Sherlock replied.
"Wait, you're actually babysitting someone?" Mary laughed as Sherlock spoke. "Getting practice on for our girl?"
John's voice was firm: "Sherlock Holmes will not be babysitting our daughter."
"That's not the point," Sherlock said. "I do have to get some---" he gestured, indifferently. "---food. For him."
John was surprised that Sherlock was so insistent on leaving, and the consulting detective immediately turned towards the door. The child had been alone in 221b for well over twelve hours, and a thought occurred to John:
"Get him a treat of some sort, would you? Like a slice of pie or something. Kid's been on his own all day, reading those bloody books you got him."
Mary thwapped John's arm. "Shouldn't fill the kid up on sugar before he takes him back to his family."
"What harm's a little sugar going to do?"
"You must know it makes them unbelievably hyper and cranky. Haven't you seen Jimmy across the street after his babysitter leaves?"
"I thought he was just like that."
There was a quiet noise as Sherlock closed the front door behind himself. Mary immediately turned to John, wide-eyed and gossipy. John loathed gossiping and everything that came with it, but he had to admit, Mary was rather adorable when she got this excited.
"He's babysitting? Who is he babysitting?"
John shrugged. "Told me his name was Arsene Lupin, but apparently that wasn't true. Really odd kid. Looks a bit like Mycroft."
"Mycroft has never been with a woman," Mary interjected.
"Well, maybe---"
"No, seriously," Mary insisted. "We can tell these things, and believe me, I can tell."
John looked at her skeptically. "Honestly."
"Yes," she said. She gestured to the door. "Better catch up with him, though. He's not going to sleep, and you don't want him performing experiments late at night with whoever the kid is still there."
"Are you sure?" Although John was certain that Mary was, he always asked. It was a pact, of sorts. She would always offer as though it were a suggestion she made, even though they both knew it was something he wanted, and he, in turn, would always ask if it was all right. It was their way of being truthful to each other. Her showing him that his love of Sherlock was all right, and he showing her that he still cared enough about them to ask.
It often astonished him that he had ever doubted their relationship. That moment in Leinster Gardens seemed like forever ago, and it took true effort to recall all of those feelings of anger and betrayal he felt that night. One day, he imagined, he would never feel them again, and he would never have moments where he might think of Mary as anyone but Mary Watson. That day was not to-day, but it would happen. Eventually.
"Go on," she said, gesturing to the door. "Text me if you work out who the kid is, yeah?"
"Love you," he said.
"Ta," she replied.
Such a strange but oddly perfect way to live. John wouldn't want anything else.
When John arrived at 221b, he found Sherlock's coat hanging on the hook, but no sign of the detective. He stepped up the stairs, remembering to avoid the step that creaked loudly. How often did he climb these stairs over the last few years? Living a life with Sherlock Holmes, then remembering the times he spent living that life. He would miss it, really. Even that one creaking stair.
At the top of the stairs, he saw the boy, sleeping awkwardly in the chair, his orchid book half-opened under one arm. Fallen asleep while reading. It was hard to say, but John wouldn't have been surprised if he found that the boy hadn't moved since they left. The books Sherlock left were in a pile on the floor, a few little pieces of paper sticking out of the sides, marking pages, or perhaps questions. Also a dictionary, which John knew Sherlock had not procured from his bookshelf. Maybe the boy brought it on his own.
On the table next to the boy was a slice of pie sitting on a new book on botany and fungal relationships, which John only sort-of knew was related to orchid growth. The idea that he might be dealing with a nephew of Sherlock's returned to John's mind. After all, such a show of affection was something that wasn't even shown to John at birthdays or Christmas (though, occasionally when Sherlock broke something that was important to John, or got him sacked from a good job.)
He found Sherlock had moved his information from above the fireplace to his own bedroom, pinning it up above the headboard. He stepped inside and shut the door.
"No rest, I see."
Sherlock shrugged. "Shouldn't have come at all, he was asleep."
John nodded. "Saw you bought him the pie."
"Mmmm, I do trust Mary's mothering skills, she was especially good with me for the few months before you got married."
John opened the door again, glancing back out at the sleeping boy.
"He's going to get a twinge in his neck, sleeping that way," John said.
"No, he'll end up back in bed before he wakes up," Sherlock responded.
"Why, does he sleepwalk?"
Sherlock turned to face John. "No, that's…what always happened to me when I was that age."
"So your parents put you to bed."
"No, I---" Sherlock blinked. "I---I suppose they did."
"What, did you think you just apparated there, or something?"
"I figured it just sort of happened."
Sometimes Sherlock's ignorance and innocence was astounding. Man of 37, thinking he just appeared in bed. He wondered about the Holmes parents. They seemed outstandingly normal, but for both Mycroft and Sherlock to be how they were…there had to be something underneath it all. He idly wondered if his own children would be this way. An ex-military doctor, and whatever the hell Mary had been before all this leading the way.
At least Sherlock approved of her mothering skills.
Sherlock was still staring at John, John realized. His eyes were wide, his shoulders tight. He actually looked very young, almost frightened.
"Sherlock," John said, stepping towards him. "What is it?"
Sherlock swallowed. "Should I---take him upstairs?"
Oh, god. Is that what he was frightened of? John couldn't help the slight smile that appeared on his face at Sherlock's fear. It was as if he'd never handled a child before, though John came to understand that this boy had stayed here before.
"Yeah," John said. "Unless you'd rather I---?"
"No," Sherlock replied. "No, I---I have it."
He stepped towards the sitting room, pausing to straighten the bottom of his dress shirt, before reaching the boy in the chair. Although a bit plump for his age, the boy was still very young, and John knew that Sherlock was surprisingly strong. He reached under the boy, lifting him up gingerly, carefully. The boy easily rolled to the side, leaning his head on Sherlock's shoulder. He mumbled something that made Sherlock pause, though John couldn't hear quite what he said. Sherlock turned towards the stairs and slowly stepped up them. He even stepped over the fourth stair (the creaky one he insisted was walked upon so that the wear would be the same and would not allow for suspecting intruders to notice the difference.)
Who was this boy? Why was he so special?
Sherlock's mobile chimed from where it lay on the bed. While John was often invited to look at Sherlock's phone (read: answer Sherlock's texts when he was too lazy to do it himself), he had the sudden feeling that looking at this text would be an invasion of privacy. That there would be something in it that he would regret seeing.
He picked up the phone, sliding it to open.
He was right.