This is not your typical role reversal fic. This is also sort of a gender bender. So while the names of the characters are retained, their roles and personalities may be switched up. I'm currently writing this while I hit a bit of writer's block for my other fic "Her Chemical Defect". Hope you enjoy this fic! This is so fun to write since I'm totally writing outside the box, but still draw inspiration from the original characters and scenarios. I also draw inspiration from the Sherlock movies and in particular, A Scandal in Belgravia episode from Sherlock BBC.

If you're looking for my non-AU Adlock fic, look for "Her Chemical Defect", which is ASiB written from Irene's perspective.

There is no such thing as fate.

No such thing as a predestined future.

There are however, choices. Decisions. And we are the ones who make those decisions, the consequences of which will dictate the course of our entire lives.

Every day, we make hundreds of decisions—from what to wear, where to eat, what route to take to work, even which way to turn our heads. Each of those decisions we make leads to the life we have now.

But what if you had made a different decision in the past? What if your parents made different choices? Or their parents before them? Would you still be who you are today? Would you be a different person entirely?

Or would your path simply have diverged into another plane of existence, so there are two, three, thousands and millions of versions of yourself simultaneously existing in the same timeline?

"That's not an account of the last case."

Mary Morstan gave a visible jolt from where she was seated and gave her flatmate a scathing look. "Irene! I told you not to sneak up on me like that."

"I didn't," Irene answered petulantly, her dark hair wild around her shoulders. "I've been watching you type and delete, type and delete and type some more for the last half hour. It's not my fault you weren't paying attention to your surroundings."

Mary pressed her lips in frustration. She had been flatmates with Irene Adler for the past four years, and yet she could never get used to how exasperating this woman can be.

She gave Irene a once over. "What on earth are you wearing?"

"I could ask you the same thing." Irene pointed with the cup of coffee she had been holding with her free hand. "That button up shirt fits very ill with your silk pajama bottoms."

"And I'm supposed to take fashion advice from someone who's wearing nothing but a sheet?" Mary retorted. "You are wearing something beneath that, right?"

"You were right on your first deduction." Irene sipped her coffee loudly and sat down heavily on her favourite arm chair, her other hand clutching the sheet to her body. "Now, can you tell me why you are writing what appear to be the beginnings of a dumbed down version of the Many-worlds theory instead of blogging about our last case?"

Mary bit on her tongue. Seriously, it was much too early in the morning for this. She eyed Irene's cup of coffee longingly but ultimately decided to humour her friend with an answer. "It's just something I've always been interested in. What if there are other parallel worlds with different versions of us? What would I have been like in that world? Would I still have been blonde? Would I still have been a nurse?" She narrowed her eyes at Irene. "Would I still have been assistant to the world's bitchiest consulting detective?"

"Only consulting detective," Irene said pointedly, placing her now empty mug on the stack of books on the coffee table. "Mary, there are an infinite amount of possibilities on how you and I could have been like if such other worlds existed. As it is, we live in a world where you are wasting your time with inconsequential trivia while there is a recently concluded case that needs to be blogged about."

"I wish I lived in another world where you don't nag me so much about blogging our exploits," Mary grumbled and turned back to her laptop. "Or in a world where we lived in a better flat than this."

"We would be living in a better flat if you did your job and blogged," Irene continued and grabbed the morning paper from the clutters of the coffee table. "That's where our clients come from."

Mary rolled her eyes and shook her head. She couldn't deny what Irene said was the truth. The blog, which detailed criminal investigations they had solved together, had catapulted Irene Adler and herself to internet stardom; and with it, came the money. A lot more than what she was getting from when she worked as a nurse, but still less than what she had been enjoying when she worked as a sniper in Afghanistan. But that was a lifetime away now. Mary Morstan was on the straight and narrow. Of course, from time to time, she'd had to shoot a bloke or two during case work, but she supposed there was a morbid kind of thrill she found there. She would never have succeeded in adjusting to civilian life had she not met and became party to the thrills of the life of one Irene Adler.

And as of the great detective herself...well, her full history was still a bit of a mystery, really. Mary did know Irene had a sister—Anthea Adler—who held a high position in the government, and that Irene had been a child prodigy, and would've graduated from Cambridge at the tender age of twenty had it not been for the drugs. Perhaps taking a degree in Chemistry wasn't so good for a very inquisitive genius who more often than not, experimented on herself. At least, that's what Anthea had told her.

As for the consulting detective gig, that had taken place a few years before they met, while Mary was still in Afghanistan. From what she understood from Detective Inspector Sally Donovan and Assistant Detective Greg Lestrade, Irene Adler had crossed the crime scene tape to look over the body of a homeless man they believed to have died from an overdose. She'd been high herself when they took her away but when she began spouting possible evidence for a murder instead of an OD, DI Donovan had it checked and guess what? The cocaine-addled Ms. Adler had been right, and she would continue to be right with the rest of the cases Scotland Yard consulted her on.

Mary opened her blog and scrolled through the very first entry: the day she had first met Irene. Mary had just arrived in London then. Suffering from PTSD, work had been hard to come by, and even harder was looking for a decent place to stay in. Luckily, she happened to run in to Sarah Sawyer, a doctor she had once worked with at St. Bartholomew's hospital, who told her about a friend who was looking for a flatmate. And that's how Mary Morstan had her first glimpse of Irene Adler—in the morgue, maniacally beating up a corpse with a riding crop as part of some sinister experiment.

"You had a fight with John, I see."

Mary swiveled her chair to glare at Irene, who was not looking up from the morning paper. She was holding the paper up with both hands, and Mary could only assume from the way Irene's sheet pooled around her waist that the woman was half naked.

Not like the detective cared for that really.

"What made you think I had a fight with John?"

This time, Irene did look up from the paper, her face still half-hidden, but with one thin brow arched in a condescending manner. "The shirt you're wearing is bunched up under the breast line, indicating that you have been crossing your arms over and over, as is a habit of yours whenever you're very upset. By the puffiness around your eyes, it is also clear that you have been crying and have not had much sleep. The slight reddening of the skin of your right ear shows indications that you have spent several hours on the phone with him to the point that the phone began to overheat, but in your anger, failed to notice that. Then there's the fact that you tried to take off your engagement ring, as shown in the way it has been moved further up from its original position but since you have gained a considerable amount of weight, you find yourself unable to take the ring off. Tell me, am I wrong?"

"I did not gain a considerable amount of weight!" Mary fumed, and much to her chagrin, found herself sucking in her stomach. "I gained a couple of pounds maybe."

"Six, if you want to be exact about it," Irene corrected. "There's only a few more months before the wedding so you better watch your weight. Oh, and better not eat that bagel if I were you."

Mary threw the pastry she had been holding to the plate beside her laptop. "Some Maid of Honor you turned out to be. You're supposed to be helping me keep my sanity and self-esteem together while I'm planning my wedding."

Irene flipped the newspaper down, her face scrunched up in confusion. "So you're still pushing through with the marriage? After your fight?"

"Yes, Irene, I am still engaged to John and I will still be Mrs. Mary Watson." Mary took a deep breath. She loved this woman, really, she did. They were each other's confidantes, best friends, partners in solving crimes and have saved each other's lives countless of times. But romantic love...despite Irene's great mind, it was something that went over her head all the time. "Just because John and I have a little tiff doesn't mean the wedding is off. Couples fight. That's what couples do. We can't expect to agree all the time. In fact, it's couples who don't fight that are in the most danger of breaking up."

Irene's lips twisted, the way it always did when she was pondering on something. "I could never understand that concept. Isn't it much more beneficial to have less strife in a relationship?"

"You will never understand until you get into a relationship yourself." Mary shook her head and turned her chair around so she was facing her laptop again. "And for God's sake, will you cover yourself up? What if a client comes in? Or Mr. Stamford?"

"Our dear landlord is away on vacation, as you are well aware," Irene muttered, but at least she did wrap herself up in her sheet again. Mary could practically hear the fabric crinkle. "Did anyone send an e-mail for a new case?"

Mary scoffed. "I haven't even started blogging about our last case and already you're looking for a new one? What about the papers?"

"Solved them all." Irene made a show of taking the morning paper from the coffee table and hurtling it towards the bin at the corner of the room. It got in, of course, but not without a rattle that made Mary grit her teeth. "Kevin Talbot's in a drug den, Mrs. McDermott had her husband murdered, and the bank manager Ian Durst was in on the robbery. I'm sending a text to Sadie Donovan now."

"It's Sally. Sally Donovan," Mary reminded. "When will you ever get her name right?"

"When she starts doing her job right," Irene shrugged, sending off the text before tossing her phone on the coffee table with a clatter. "I don't know how she managed to be Detective Inspector with that dismal track record."

Mary rolled her eyes. "If you're so good why don't you apply for the DI position?"

"And be surrounded by the idiots of Scotland Yard?" Irene seemed genuinely appalled. "I'd much rather put a gun in my mouth and shoot myself in the head."

"Most people would prefer if you did," Mary charged back, though not without a hint of amusement. This exchange was commonplace between her and Irene. It was almost a daily ritual. "Now pipe down so I can start blogging. Then, I'll look and see if we have any new cases."

"But I need a new case now," Irene whined and started pacing, or rather shuffling back and forth the sitting room. "It's been more than twenty four hours since the last one. I'm bored!"

"Well, why don't you go to St. Bart's, hm?" Mary suggested with a tight, patronizing smile as she began typing a new blog entry. "You know, go out, get a look at some freshly deceased body? I'm sure Anderson wouldn't mind your company."

"I already texted Anderson but it doesn't look like he got any interesting corpses for me." Irene grabbed her phone then practically shoved the screen in front of Mary's face. "And will you take a look at his reply? I mean really. Why does he always end his text messages with invitations for me to go have coffee with him?"

Mary shook her head. Dear God, this woman was dense. "He likes you, Irene. I've been telling you that for years."

"Well, of course he likes me," Irene said as-a-matter-of-factly. "I've been making his job a lot easier. He barely does anything when I'm there except stare at me like some imbecile. Though I have to admit, he does know how I like my coffee. Maybe he should have been a barista instead of a coroner. Is that why he keeps on inviting me to go out for coffee?"

Mary sighed. No use explaining these things to Irene. It was just a waste of time. "Why don't you check with Anthea? Maybe she needs you to save London again from another terrorist attack."

"If Anthea wants my help, she'll come here," Irene grumbled and resumed pacing behind Mary. "I may be bored, but I'm not desperate. If she has a case for me, she'll have to come fetch me."

"Then, I guess I came just in time, baby sister."

Mary looked up from her laptop. Sure enough, Anthea Adler stood at the doorway, her dark brown hair in perfect waves down her shoulders, her black dress suit impeccable. Flanking her were two men in equally dark suits.

"Hello Mary," Anthea greeted, giving a nod to Mary though her eyes remained on Irene. Mary watched as the Adler sisters looked at each other in silence, the air thick with their obvious disdain for one another. "Baby sister, would you be a dear and change into something more decent? We have men in the room."

Irene shrugged, the sheets coming down her shoulders a little. "So? By the looks of it, these men are patrons of some rather unsavoury pubs so they shouldn't be so surprised by the female form, especially since I'm a little more clothed than those women." Irene directed herself at the men. "You both still have some body glitter on you."

"I have a case for you," Anthea cut in. The men with her were looking at everywhere but the Adlers. "I've come here to take you to your client."

"You know very well that I only entertain clients in my flat, Anthea. Tell him he has to come here if he requires my services. Good morning." Irene pivoted and started for her room when Anthea stomped on the tail of her sheet, almost causing it to fall off her body were it not for how tightly she was clutching it.

"You've already deduced who your client is," Anthea hissed. "So stop acting like a child. He does not have the luxury of time nor can he afford the publicity if he were to come here himself."

"P-Publicity?" Mary finally found the urge to speak up, turning questioningly to Anthea. "Who's the client?"

"Only one of the most powerful men in all of Europe, and in consequence, the world," Irene answered, and with a haughty smile, turned to her best friend. "The British Prime Minister, Mycroft Holmes."

That's it for now. Hope this is intriguing enough for you guys. I'll try to post once a week, every Saturday if I can. In the meantime, feel free to sound off your comments :) Would love to hear from you.