A/N: I promised myself that I wouldn't start any more WIPs until I wrapped up my other ongoing stories, but I just couldn't help myself! I've had this story idea floating around for awhile. This story is set Post Season 1, but Pre-Reichenbach Fall. Although I will work in some events from season 2 and season 3, there will also be a fair amount of canon divergence.

The title of this work is a reference to the Jonathan Swift satire by the same name. Also, for any of you ACD fans, this first case is based on the Sign of the Four. Enjoy!

Chapter 1: The Proposition

John is sitting in his chair, reading the morning paper, when Sherlock walks in from the other room, and stands directly in front of him.

At first John ignores him, but when Sherlock continues standing there wordlessly, John sets down the paper, and looks up at the other man, who seems even more imposing than usual when viewed from a seated position

Sherlock seems serious, but not upset, so all John says is, "Can I help you?"

"I've come to a decision."

"Okay, sure." A pause and then, "About what?"

"I think it's time for you to stop dating.'

"Hold on—"

"It's clearly a waste of time—both yours and mine. I have to go solve crimes on my own while you're off courting women that you obviously can't stand."

"That's not true. I really liked Lisa—"

"Do you remember her birthday? Her mother's name? Her occupation?"

"She was," another pause, "a librarian."

"Nope—secretary."

"How do you remember that?"

"I don't! I have no idea what she did, and clearly you don't either."

"So, I should just stop dating women because you think it's pointless?"

"Precisely."

"Even by your standards, this is utterly insane."

"It's perfectly logical."

"No it isn't. Besides, this isn't about logic."

"Everything is about logic."

"Not love."

"You didn't love any of those women."

"Um, no, not really."

"Have you ever loved any woman? And I don't mean your mother or your lesbian, alcoholic sister."

"I just haven't found the right person yet."

"Or maybe there is no right one."

With forced optimism, John retorts, "I guess I won't know unless I keep trying."

"Why do you insist on being so painfully, willfully dense?"

"Sherlock, if you're going somewhere with this, you're going to have to spell it out for me, because quite frankly, I have no idea what you're going on about."

"It's not my fault that you're an idiot!"

"Um, okay. Can I go back to reading the paper now? Or do you want to forbid me from wearing jumpers too?"

"I'm sure the king of England couldn't prevent you from wearing your beloved, thread-worn, misshapen jumpers."

"Well, maybe if we had a king, but we don't—which you would know if you spent more time reading the paper and less time making decisions about my love life."

"Or lack thereof."

With those final words, Sherlock turns on his heel and throws himself into the chair opposite John. In one fluid movement, he wraps his arms around the union jack pillow, clutches it to his chest and puts his feet up on the coffee table, deliberately on top of the newspaper.

John forcefully yanks the papers out from under Sherlock's feet, while Sherlock just stares petulantly at the floor.

Under his breath, John mutters, "If Lestrade doesn't find you a case soon, I'm going to go on a killing spree just to get you out of this bloody flat for a day."

"Don't bother. I'm sure any murder you attempt would be trivially easy for me to solve."

"Cocky bastard."

Sherlock shrugs, and a smile pulls at the corner of his lips, as he forgets for a moment that he's supposed to be sulking, but then the next second, his features turn serious, he pushes himself out of the chair, goes to his violin, and begins to play angrily.

For his part, John shrugs and returns to reading the paper.

Later that evening, Sherlock in reclining on the couch, staring up at the ceiling, when John comes down the stairs.

Without even bothering to sit up, Sherlock remarks, "Going on another date, I presume."

"Um, yeah. How did you know?"

"Lucky guess."

"Really?"

Now Sherlock sit up, with a movement so sharp that it is almost startling.

"Of course it wasn't. I never guess! Guessing is for people who are blind and witless."

"Like me."

"Like you and Lestrade and the rest of the ignorant world."

John opens his mouth to respond, but Sherlock jumps in with his deductions before John can get out a single syllable.

"First of all, that sickening cologne—it's expensive, so you only use it on dates, although I've worked with laboratory grade chemicals that smell more enticing. Maybe that's why you almost never get further than—"

"Sherlock —"

"And then that bloody jumper you're wearing. I hate it, but you love it. You never wear it when we're on a case or when you're going out for a night at the pub with Stamford."

"Okay, I suppose—"

"And I can tell you're planning on taking her for a nice romantic walk."

"You couldn't possibly—"

"Your shoes—not your nicest pair, so not typical date shoes—but comfortable for walking—and your coat is heavy enough to be worn for extended periods outside."

"Are you done yet?"

"I could go on."

"Yeah, you probably could, but you'll have to save it for later or share your commentary with the skull. I can't be late for dinner."

Before Sherlock can say anything else, John is out the door.

When John returns home—just a few minutes past midnight—the lights are all out at Baker Street, which is odd.

Rather early for Sherlock to be asleep. Maybe he's gone out?

A moment later, John dismisses the thought. No chance of that. Sherlock would only have left the flat for a case, and if there had been a case, Sherlock certainly wouldn't have hesitated to interrupt John's date to inform him.

Sleeping it is, then.

Deciding to be quiet so as not to wake Sherlock, he carefully tiptoes up the stairs and gently opens the door to their flat.

The first thing he notices is the strong smell of tobacco.

Definitely best not to wake Sherlock. If he's been smoking in the house, there's no telling how irritable he could be.

John doesn't bother turning on the lights as he takes off his coat and prepares to hang it on the door, but then he's startled by—

"So I take it the date was a success?"

John turns around sharply to see Sherlock lying on the couch.

"Jesus Christ, Sherlock, you can't do that."

"Do what?"

"Pop up out of nowhere."

"I didn't come out of nowhere. I've been here the whole time."

"Yeah, but normal people don't just lie in the dark waiting to give their flatmates a heart attack."

"You've survived a warzone. I'm pretty sure it would take more than this to give you a heart attack."

"I'd really rather not test that theory out."

John sinks down into his chair, as Sherlock asks, "So, how was the date?"

"You don't really want to know, do you?"

"No, not particularly."

John catches sight of Sherlock's arm, the sleeve rolled up, and three adhesive patches on his forearm.

"Sherlock! You're not supposed to smoke with nicotine patches on."

"Why not?"

"Because that's not the point of them! And because it's not healthy to have that much nicotine in your system at once."

"I'm bored, John. I can't stand it."

Sherlock throws the cigarette butt into the fire. When he glanced over, John sees an entire pile of extinguished cigarettes littering the hearth.

"Bloody hell, Sherlock."

"So much profanity, John. I hope you don't use that kind of language in front of your new paramour."

"You mean Cynthia?"

"What a common name."

"I think it's a nice name."

"You think everything is nice."

John has his mouth open, ready to fire back a retort, when Mrs. Hudson comes bustling up the stairs.

"Sherlock, did you disconnect the doorbell again?"

"Maybe."

"You've got a client."

John lets out a grateful sigh, "Thank god."

"Is it that portly accountant again? I already told him, his wife is the one—"

"It's a woman. A very pretty one, in fact. She says her name is Mary Morstan."

"Is her husband having an affair? I'm so tired of—"

"Actually, Mr. Holmes, I'm very much unattached."

And with those words, Mary Morstan walks over the threshold and into the flat.

Looking around, she adds, "Well this place certainly has a lot of, um, character."

Embarrassed, John starts grabbing handfuls of lab equipment and sweeping aside piles of papers in a vain attempt to make their flat look like less of a disaster, while Sherlock just makes a face and rolls his eyes.

In response, John says, "You could give me hand with this. After all, this is mostly your mess."

"Why bother?"

"Because we have a client."

"She's not a client until I decide whether I want her to be one."

"Fine, a potential client."

"Are you sure you don't mean a potential girlfriend? Because you didn't go to all this trouble when that obese porn addict with a heart condition burst through our door."

John is prepared to fire back a retort, but before he can say anything else, Mary clears her throat and interjects—

"The potential client is standing right here. You can stop talking about me in the third person."

Flushing with embarrassment, John says, "Yeah, sorry, we don't get much company."

Playfully, Mary says, "I can't imagine why not."

"Maybe it's because I'm a high functioning sociopath."

"Don't listen to him. He doesn't actually mean that."

"Um, yes I do."

"Sherlock, for once in your bloody life, could you just shut up."

"Only if you could go one night without throwing yourself at yet another female conquest."

"I am not—"

"Yes, you are. Look at you! You practically started salivating the minute this woman walked into the room."

"I did not—"

Their back and forth is interrupted by the sound of Mary chuckling to herself.

Seeing her amusement, Sherlock turns on his heel and throws himself down on the sofa. For his part, John smiles sheepishly.

Once she stops laughing, Mary starts to ask, "You two aren't a—" before trailing off.

"Aren't a what?"

"A couple."

John says, "Oh god—no—how could you—no, we're single. Both of us."

Sherlock clears his throat loudly.

Crossly, John asks, "What?"

"What about Cindy?"

"Who?"

"Your girlfriend. That woman that you were just telling me about—"

"You mean Cynthia?" Redirecting his attention to Mary, John says, "She's not, I mean, we're not—"

Mary smiles warmly at John's obvious discomfort, making Sherlock bristle.

"Did you come here for a reason, Ms. Morstan? Because I am quite busy—"

"No you're not. We haven't had a case in a week. You're practically climbing up the walls—"

"Yes, Mr. Holmes, I do have a case—one that I hope you'll be able to help me with. If you would be willing to spare me a couple moments of your time."

Sherlock doesn't say anything in response, but John graciously steers Mary to an empty chair, before sitting down in the other armchair. Meanwhile, Sherlock continues to lie on the couch, staring up at the ceiling.

Mary hesitates, but at John's encouraging look, she says, "I hope you'll forgive me for intruding at this late hour."

"Don't worry, Sherlock's always keeps us up all hours of the night."

Mary raises her eye brows and says, "Oh really?"

Blushing again, John stammers, "Not—not like that."

Before Mary can say anything else, Sherlock interjects, "Could we get on with this?"

"Yes of course. I think I have a matter that you will find very interesting. It pertains to my father. He was a military man—"

"Your dead father."

Sharply, John hisses, "Sherlock, we've talked about this."

"About what?"

"Tact."

"Tact is boring."

Mary seems unperturbed, and says, "Yes, my father passed away a number of years ago, although I'm not sure how you could have known—"

"It's quite obvious, really."

Sherlock pauses, as John lets out a deep sigh at the impending show-off routine. Sherlock gives him a sharp glare before diving in—

"That ring, on your finger—a man's ring, evident both by its design and by the fact that it had to be resized considerably to fit on your finger. It's old, although well cared for, but not of suitable quality to be a family heirloom. You are smartly dressed, but that ring is not particularly fashionable, so clearly of sentimental value. And this is without getting into the very telling way that you nervously started fiddling with it as you were speaking. And presumably if your father were still alive, you would not have taken to wearing it."

"Very impressive, Mr. Holmes."

"Hardly."

"Well, I'm impressed, and you are right on all accounts. That ring is one of the only things that he left behind when he died."

"So your father's death is the reason you've come to me. But why now?"

"I received a package, in the post, the other day."

"And what was in this package?"

"I have it here."

Mary reaches into her bag and carefully lifts out a small bundle wrapped in cloth, and then gently unfolds it from the cloth.

Sherlock reaches for it, but before she hands it over, Mary cautions, "Please don't touch it directly."

Sherlock shoots her a curious look, but he follows her lead, cradling the object using the cloth, careful not to touch it.

Curious, John stands up, and goes to lean over Sherlock's shoulder, and as he catches sight of the object, he says, "It's a doll."

Sarcastically, Sherlock fires back, "Brilliant deduction, John. Anything else you'd care to share with us?"

Without giving John a chance to respond, Sherlock says, "It's a matryoshka doll."

"A matr—what?"

Mary answers before Sherlock has a chance to. "A Russian nesting doll. I collected them when I was a girl."

"You did?"

"Yeah, well, my dad got me started with it. He was always bringing them back with him."

"Back from where?"

"His travels—work related."

"For the military?"

"I suppose, although it wasn't really something we discussed."

Sherlock pauses, lost in a thought for a few moments, before saying, "Why now?"

"Sorry?"

"Why are you coming to me tonight, at what you already noted is a very late hour?"

"Well I received the package and—"

"Ah, but you didn't receive the package today, did you?"

"No, like I said it was a few days ago—"

"But you just got the results back today."

Suddenly interjecting, John says, "Results? What are you on about, Sherlock?"

Mary answers before Sherlock can respond. "Yes, I did just get the results back today, Mr. Holmes."

Suddenly looking very interested, Sherlock leans in and asks, "So were they his?"

"Yes, they were."

"But this is where it gets even more interesting, isn't it?"

"Yes, but it's even more curious than that because—"

Sherlock finishes the sentence for her, "His were the only ones."

Frustrated, John interrupts again, "Would you stop talking in bloody riddles?"

His eyes still glowing with interest, Sherlock says offhandedly, "Fingerprints, on the doll. Her father's fingerprints, and only his."

Mary asks, "So how did you guess?"

"I never guess."

Warningly, John says, "Sherlock—"

"You were clearly quite keen not to have me touch the doll—that in itself was more than enough of a clue. And of course, if you had this checked for fingerprints and they were inconclusive, why would you care who touched it?"

"Mr. Holmes, I do hope you are able to make such quick work of the rest of this puzzle."

Suddenly in very good spirits, he says, "Call me Sherlock. I'm sure we'll be spending plenty of time together."

"Oh we will?"

"Yes, I'm going to set aside all my other cases to focus on this singularly interesting one."

"You don't have any other cases."

"I might."

"You don't."

Mary can't help but start laughing again at their bickering. "You both really are too much."

John opens his mouth to respond, but once again Sherlock has returned his focus to the case. Gently shaking the matroyshka doll, he says, "It's empty."

"Yes, nothing inside."

Still using the cloth as a barrier, Sherlock gently separates the two halves of the doll, and then stands up, and moves closer to the light, and carefully scrutinizes the inside.

After long moments of silence, John asks, "See anything useful?"

"No—no writing, no markings."

After examining the inside of the doll, Sherlock looks more closely at the outside, and asks, "Do you still have any of the others?"

"The other what?"

"The dolls, that your father gave you."

"Yes, I should have all of them. They're in storage, of course."

"Excellent. Bring them to me tomorrow, along with the original package that this came in."

Mary hesitates, "I might have thrown that out."

Sherlock gives her a sharp look, but John says, "Well, bring us anything you have."

"Yes of course. Would six o'clock tomorrow be all right?"

"Perfectly fine for me, although I believe John here might be otherwise engaged."

"No, I don't think so."

"Are you forgetting about your dinner plans?"

"How could you possibly know—"

"I nicked your phone and read your calendar while you were bathing in that putrid liquid that you call cologne."

"Sherlock—"

"Really, John, going out with Cindy—"

"Cynthia—"

"Fine, Cynthia—and then the next night making plans with Martha? It's a wonder that you can even hold down a job. Oh wait, you don't have a job."

"The only reason I don't have a regular job is because I have to work around the clock to make sure you don't blow up the city."

Sherlock looks like he's about to take the bait, but instead he says good naturedly, "Ah, well, work is boring."

Then, turning back to Mary, he adds, "But this case promises to be very interesting."

"So you'll take it?"

"Absolutely."

Cheerily, Mary says, "Then I suppose I will see you two boys tomorrow."

Mary makes her way to the door, and John jumps out of his seat, to get the door for her.

Once Mary is gone, John says, "Well she seems nice."

"Who?"

"Mary."

"Already on a first name basis, are we?"

"Well you told her to call you by your first name."

"Yes, but that's only because 'Mr. Holmes' makes me feel like I'm impersonating Mycroft."

John doesn't bother responding, because he can tell that Sherlock has already tuned out the rest of the world, as he stares at the doll where it lies in the middle of their kitchen table.

Shaking his head and smiling to himself at his friend's single mindedness, John makes his way up the stairs leaving Sherlock to bask in the promise of a very interesting new case.

A/N: We'll get a lot more details about the case and the circumstances surrounding her father's death in the next chapter, but this chapter was already getting pretty long, so I decided to save the rest for later. Also, this story is not going to be a John/Mary romance. The main relationship is definitely going to be John/Sherlock, although they have a lot of stuff to sort out first.

Anyway, I'd really love to hear what you thought of this first chapter! Thanks for reading :)