Disclaimer: This fic is just for fun, and I don't own anything related to BBC Sherlock. Well, I own the Blu-Rays of both series, but that's not what we're talking about here.

Note: This story was originally posted on the Sherlock BBC Kink Meme. It was then cleaned up a bit and posted to Archive of Our Own. I received a couple of private requests to bring the fic here as well, so here we are.

First, DI Greg Lestrade stumbled out the door of 221B Baker Street. His dazed expression and rubber-kneed walk gradually evened out, and soon he was striding along briskly and muttering curses under his breath.

Second, he popped into an art supply store and bought a large notepad and a thick permanent marker. He kept grumbling profanities as he fumbled for coins, but managed to politely thank the checkout clerk, an old woman in a hand-knitted cat-themed jumper, who might as well have been putting herself up for consideration in the Disapproval Olympics.

Third, he found a convenient CCTV camera at an intersection. He uncapped the marker using his teeth and wrote large, bold words on the pad, which he held up in direct view of the camera.

"MYCROFT HOLMES, WE NEED TO TALK."

He looked down at his writing, obviously contemplating something. Once again, he cursed. With a few more strokes from his pen, he added:

"NOW."

Several minutes went by. Lestrade huffed and took to the pad again.

"SHERLOCK-RELATED."

If he weren't still set on being so upset with "bloody-minded Holmeses", he would have been impressed with the fact that it took a mere thirty seconds for the car with tinted windows to arrive. But his unsettled irritation knew no bounds, so when he took his seat, he settled for merely grumbling, "About bloody time."

Lestrade sighed, crossing his arms over his chest and scowling a bit at his surroundings. Even if he weren't already feeling thrown for a loop and generally frustrated by the day's events, being blind-folded and led to where he now sat certainly didn't improve his mood. With grey, featureless walls and lighting that fluctuated wildly between too bright and too sparse, the place screamed 'secure location'. It was strange, in a way. Why go to so much secretive effort over a man who had been dead for over five months?

He tried to put it down to damnable Holmes dramatics, but something about it still rubbed him the wrong way.

Speaking of ridiculous dramatics, Lestrade turned his head as he heard the creak of the room's only door swing open. The clack of pristine dress shoes heralded Mycroft Holmes' entrance.

"Ah, Detective Inspector, to what do I owe the pleasure of your company?"

Lestrade rolled his eyes. "You saw my note."

"Yes, but I'm afraid you'll have to be a bit more specific. This past year has seen so many things be 'Sherlock-related', as you put it."

"Understatement of the century, that." Lestrade sighed and rubbed the back of his head. "It's, ah. John-related as well."

Mycroft's lips tightened slightly. "Go on."

"I went to Baker Street to check up on Mrs. Hudson and he's -. Look, it's- I mean- You should go visit him," Lestrade finished lamely. Upon seeing Mycroft's thoroughly unimpressed look, he continued, "I'm a Beta, right? This whole… Alpha-Omega business isn't really my field. You're an Alpha, like Sherlock. You figure something out."

"I assure you, his bonding with my brother absolutely does not mean that John can just switch to me. Nor would either of us, John especially, be amenable to-"

"That's not what I meant and you bloody well know it!" Lestrade barked. His voice echoed back to him in the small chamber. He groaned and continued, "Sorry, sorry, didn't mean to yell. But just go visit him, okay? He's back at the flat he used to share with Sherlock, though I probably don't need to tell you that. You'll know exactly what I'm yammering on about the minute you walk through the door."

"I shall take it under consideration," Mycroft said, straightening his lapels. "If that is all, I will be taking my leave. Have a pleasant day, Inspector."

"Yeah, you too."

Again, the sound of Mycroft's shoes echoed throughout the room, followed by the opening and shutting of the door. After several minutes of silence, Lestrade knit his brows together in confused irritation.

"Am I supposed to leave on my own? I don't even know how I got here!"

"I shall notify you when I am ready to be picked up," Mycroft told his driver as they pulled to a stop in front of 221 Baker Street. Mycroft saw the driver's head nod in agreement through the rearview mirror. "Remain in the area regardless."

He stepped out and squinted in distaste as the glare of the setting sun reflected off the departing car into his eyes. He strode over to the door of 221B and knocked sharply, clearing his throat as he waited. He knocked again and heard Mrs. Hudson's voice call out, "Coming, coming! Just a moment now!"

"May I help yo-," the elderly Beta woman began as she opened the door. Her eyes lit up in recognition. "My goodness, Mycroft Holmes! It certainly has been some time, not since the dreadful-."

"Yes. Quite. If you'll excuse my shortness, Mrs. Hudson, I'm here to pay a visit to Doctor Watson."

Mrs. Hudson nodded understandingly. "Of course," she said, stepping aside and inviting him in. "Though I do so hope it isn't about anything unpleasant. The last thing he needs is a shock or a scare. Not in his condition, the poor dear."

"Condition?" Mycroft asked, but the moment he stepped through the door, he required no more clarification. The scent shot through his nostrils and lodged in his brain immediately, and his mind supplied him with overwhelming instincts immediately:

Omega. Pregnant. Relative. Protect.

He tried to shake off the call of his baser nature and allow his conscious thoughts to take over again, but it proved a decidedly difficult task with that scent thick in the air of the flat. He made it to the living room, where he saw visual proof of what his nose had already told him.

There was John Watson, looking quite surprised at seeing Mycroft. He had apparently been doing some tidying up (Nesting, Mycroft's instincts supplied), and was reaching up to dust the mantelpiece. His shirt – a white button-down with the far too long sleeves rolled up (Sherlock's?) - was pulled up slightly, and Mycroft noted the distinct swell in the shorter man's abdomen. Just over five months pregnant, if Mycroft had to guess.

John frowned, turning to Mycroft and pulling his shirt down quickly. Despite that, he didn't appear inclined to deny what he already could tell Mycroft knew as an undeniable fact. His left hand settled on his abdomen, and he rubbed the small bump there in a few protective circles. Even though he cleared his throat, his voice was thick when he spoke. "What're you doing here, Mycroft?"

"At the moment?" Mycroft asked, sitting down as he finally felt the cloud of blind instinct start to clear and the familiar weight of conscious thought settle back down on his shoulders like blocks of lead. "Marveling at my younger brother's ability to leave behind such staggering messes."

A faint, twitching smile played upon John's lips. "Yeah," he sighed. He cleared his throat again and pinned Mycroft with a very intense look. "Shame it seems to be genetic."

Mycroft chose to let that by without comment. He simply asked, "Did he know?"

"No," John said, shaking his head. He sat in his usual chair and his hand lay over his belly, clearly a now firmly-entrenched habit. "I didn't even know until weeks after the funeral. Most pregnant Omegas don't develop the scent change until two or three weeks in, and that's for normal, healthy people who aren't choking on grief."

Mycroft frowned. "You had to have known, or suspected at the very least. You had your heat, after all."

John squinted and rubbed at his temples. "Severe stress can mess with an Omega's heat cycles: delaying it, causing it to come prematurely, rushing it. I was about a week and a half away from my normal heat, and the situation got to me. Yes, it came at me too quickly for me to take my contraceptives, but it was also the shortest heat I've ever had and it wasn't long before I was distracted by things far worse than skipped pills."

"I see," Mycroft said. A long, uncomfortable pause settled over the two for a few moments before it was interrupted by Mrs. Hudson. Her presence took Mycroft slightly by surprise; he'd forgotten the elderly woman was even around, wrapped up as he was in the shock of discovering John's pregnancy.

The old woman carried a tray topped with two cups of tea and the associated cream and sugar, a tall glass of milk, and a plate of small ham sandwiches. "For you, Mycroft," she said, placing one of the cups of tea in front of him. "And for you, dearie," she said to John in a significantly sweeter voice as she set the milk and sandwiches before him.

John chuckled softly. "Mrs. Hudson, you really shouldn't have. You aren't the housekeeper, after all..."

"Ah, ah," Mrs. Hudson tutted, waving a hand in the air. "I won't hear another word. You've barely had a thing to eat all day, for heaven's sake. Your little one needs all the nutrition he or she can get, you know."

"Thank you, Mrs. Hudson," John said. His voice was quiet and thick with emotion. "I feel terrible imposing on you like this, especially since I had to leave the surgery."

"I just said I wouldn't hear another word, John Watson! Besides, you will be paying me back later by allowing me to spoil that baby rotten." Her eyes turned a little softer, mistier. "You know I… I always did see you and Sherlock like the sons Mr. Hudson and I never had, it being tricky for us Betas and all, and that's probably for the best at this point, what with everything that happened there, and… oh, look at me babble, I must look a sight."

John reached out and laid a hand on her shoulder. He gave her a tight smile and blinked a lot in an attempt to cover up the sudden wateriness in his own eyes. "'Allow' you? I'd be honoured for my child to call you grandmother, Mrs. Hudson."

She pulled a handkerchief from a pocket and dabbed at her eyes. "Oh, John," she whispered. She sniffed and laughed nervously as she stood. "I'll just – I'll just be a moment. Need to attend to something."

John and Mycroft tried to give her privacy as she attempted to outrace the sobs.

Mycroft cleared his throat. "I shall ensure that your rent and living expenses are covered as long as necessary."

John gaped at him. "You can't be serious-"

"I am always serious, Doctor Watson," Mycroft said. "It is what my brother would have wanted."

John frowned, looking down at his abdomen, where his thumb rubbed his belly distractedly. "Sherlock always said he didn't want children..."

"Sherlock also always said he would never meet an Omega worth talking to for five minutes, that he would never bond with anyone, and that he would never find anybody whom he considered more important than himself," Mycroft stated. "Your ability to make yourself an exception to all of Sherlock's rules is really quite impressive."

John didn't respond.

"I realize you are a proud man, doctor," Mycroft continued. "And if you no longer wish to receive monetary assistance once the child is born and you are able to return to work, I shall respect your wishes. However, at the moment, allowing you access to the family funds is imperative for the most beneficial outcome for all of us." He leaned forward, eyes grim. "We both know why you're so hesitant to leave the flat for extended periods of time, to muddy what remains of Sherlock's scent. It's not all sentimentality."

John swallowed and finally looked back up to Mycroft, his face drained of a bit of its color and a hint of bleakness in his eyes. "Then you know the rate of miscarriage or stillbirth in pregnant Omegas denied the scent of their bonded Alphas."

"Seventy percent."

"Seventy-five point nine, Mycroft," John whispered. "With increased chances of cot death in infancy."

Mycroft sighed. "I could visit frequently. There have been some studies which indicate the presence of Alpha relatives of the… unavailable Alpha has a positive effect on the survival odds of fetuses in such a situation."

"And just as many studies that claim no change or even a detrimental effect."

Mycroft shut his eyes tight and took in a deep breath. "What do you have to lose?"

"You... you really have to ask?" John laughed, softly and disbelieving. "Absolutely everything."