A/N: Due to length, I had to cut this chapter in half, so one more is on it's way. (It's already half written, so it shouldn't be a terribly long wait. I need to take a minute here to praise MizJoely, who is a hell of a beta and a SAINT to put up with my moronic mistakes. It takes a special kind of woman to beta work for someone who spends 90% of her time in a fibro fog and has a mental block on seeing her own mistakes.

Thank you to everyone who reviewed, sent me messages on and tumblr, who have poked and prodded and kept me working on ASA. You guys are the BEST. Especially Nocturnias, who I'm going to have to get all gushy here and say is one of the dearest friends I've ever had and always listens to me ramble about my story ideas and plotlines.

Disclaimer: I own nothing.

It's a dangerous game, one they play with ever increasing stakes as Molly's heat comes closer. Sherlock gives an order, though not always with words; sometimes it is a flicker of his eyes, a hand motion, an imperious stare. Molly doesn't ignore it (that would be too easy). No, she outright disobeys.

On Monday, Sherlock gestures for Molly to sit beside him when he tromps down to Mrs. Hudson's flat and finds them enjoying tea. She gives him a sunny smile, shakes her head when Mrs. Hudson isn't looking, and spends a further half hour pouring over celebrity gossip rags with Sherlock's landlady.

Sherlock eats lunch (his original purpose no doubt, as Molly knows he and John have mostly mold, the lungs of a non-smoking 67 year old male, and ketchup in their refrigerator), but it is with a decidedly sulking air. After Molly excuses herself by kissing Mrs. Hudson's cheek and promising to drop by again soon, Sherlock stands to leave with her.

"Hopeless at catching a cab," he grumbles while she scoops up her purse. "It takes you ages. I'll do it for you, as I have nothing better do with my time. Dull."

Taking her her into the entry way, Sherlock closes the door before fingering her so hard Molly sees stars. The entire time all she can think is that Mrs. Hudson could step through one door at anytime, while John could be coming through the other without a second of warning, and it takes hardly anytime at all to be on tiptoes, nearly biting her lip off to keep quiet.

Sherlock pulls away before she finishes ("You son of a bitch, what are you – Sherlock, please, I'm sorry, I'm sorry, I am – please –" all spoken in a ragged, desperate whisper). Quickly he licks his fingers clean, straightens her clothing, and pushes Molly out the front door. A cab is rapidly hailed, as he seems to have some sort of mystical control over all the taxi drivers, and Molly is sent on her way with a smug smile.

Two hours later Sherlock arrives on her doorstep. Molly has him on the floor within a scant few seconds. The door to her flat's left half open and his cock is down her throat, but it's glorious and she couldn't care even if everyone she knew was in the hall watching.

Tuesday night, while working in the lab, he says, "Coffee, Molly."

Molly answers without looking up from her own work. "Yes, please. Three sugars, two creams."

John nearly hurts himself laughing. Sherlock looks as though he's bitten into a lemon. And Molly – well, Molly tosses Sherlock a wink before absconding to her office.

Later, when John steps out to take a phone call from his girlfriend Mary, they indulge in a truly furious snog. Molly ends up losing her glasses (she will later find them under a filing cabinet), earns herself several new bite marks (not easily hidden, damn that man), and practically falls apart when Sherlock fists a hand in her hair and threatens, "Next time I'll turn you over my knee, and you won't sit comfortably for a week."

It's dangerous, pushing an Alpha as on edge as Sherlock is. But Molly can't stop – any Alpha can snarl and bite and fuck. He needs to earn Molly, and she enjoys watching the threads of his control fray and snap.

On Friday, Sherlock calls at noon. "I've finished the case. It was the brother. Come over now."

"Congratulations on another one solved," Molly praises while flicking through the items in her closet. She has to bite her tongue to keep from eagerly agreeing – two days without Sherlock felt like an eternity. She hopes this neediness lessens once they've gone through a heat together; as much as Molly loves the man, sometimes she worries she will be lost inside him. "But I can't come over, not yet. I'll make it around... nine?"

"Nine?" Sherlock repeats, disbelieving. "What do you mean, nine?"

"Nine, Sherlock, nine o'clock in the evening. I'm having lunch with my sister and we're going shopping, then we're meeting my brother-in-law and having dinner. I may make it by eight or eight-thirty, but I'm not sure... You're welcome to join us for dinner, if you'd like." There, an olive branch has been extended. While she doubts Sherlock will attend a dinner that would no doubt be classified as a double-date with her sister Denise and her husband Rodney, surely he will see the offer for what it is: a compromise.

There is a long moment of silence. It is not a comfortable one.

"No," Sherlock finally says, all firmness and Alpha anger. In her mind, Molly can see him baring his teeth and clenching his hands into tight fists. "Reschedule. Cancel entirely. It's been two days, and I –" A sharp cut off. Whatever he might have said, and Molly thinks she knows what it was, is replaced with, "I want you."

"I'm sorry, but you'll have to wait," is her answer. "I missed you, too...I still do, but I've neglected my family recently."

Sherlock hangs up. Molly sighs and ends the call, pitching her mobile to the top of her dresser.

Boundaries are hard enough to establish with a regular Alpha. With Sherlock they could prove impossible. But she asked for this – wanted it for so long, truthfully... now she has it, and they're both just going to have to keep muddling through until they figure out the basics of working together.

By three in the afternoon, John texts her please for the love of God fix this before I kill him. It is rapidly followed by Molly, seriously, call him or something. I haven't seen him like this in a long time. If ever.

I won't reward him for throwing a tantrum, Molly sends back, but if I were you I'd be gone from Baker Street by 9PM. It's when I should arrive.

Forty minutes later, Sherlock arrives at the park Molly and her sister are at. They're eating ice cream and just talking. Admittedly the conversation has turned to Sherlock, though only after nearly an hour of discussing Denise's three children. It's so nice to talk about her relationship with Sherlock with someone who understands. Denise is an Omega as well, and has been Bonded for eleven years... which means she can give Molly invaluable advice, as she has gone through all this before.

"It's a fight in the beginning," Denise explains. "When Rod and I first got together, we fought nearly as much as we... you know. He has the instinct to dominate, but you have the instinct to test him. It's going to be like this until you're both secure in the relationship. It'll flair back up once in a while, but once you've Bonded, it's a lot better."

"If we Bond," Molly stresses, still not ready to get her hopes up.

Her sister answers with amusement and quirked up eyebrows. "Yeah, if. Say, isn't that...?" Pointing over Molly's shoulder with her spoon, Denise shifts her attention to something else.

Molly turns to discover not something, but someone. A specific someone named Sherlock Holmes, who is at this very moment storming up to them. His coat flares dramatically and he wears a thunder cloud as an expression.

"Oh, goody," Molly's sister laughs, "I've never been on the outside looking in on one of these. Always wondered what it looks like to other people. Good luck, sis."

"Good luck?" Molly manages to ask, before Sherlock has come around the bench and pulled her upright by one arm.

"'I won't reward him for throwing a tantrum?'" he snarls, stinking of rage, sweat, and dominance.

Molly wants to collapse on her knees and beg him to not to be angry; she'll be good, she promises, she swears it on all the stars and the sun and the moon. On the other hand, she wants to shove him hard and run, run until her lungs collapse and her legs give out. Wants him to run after her, to catch her, to sink his teeth in the back of her neck and rip her clothes and fuck her so hard she bleeds.

Looking to Denise for guidance (she knows how to handle an enraged Alpha, maybe she has a secret technique that will lull them into a state of complacency that doesn't involve orgasms), Molly sees only the gleeful face of a sister this close to taking pictures. Denise does shake her head twice, a silently communicated now you fucked up, before Sherlock's fingers are pinching Molly's chin and forcing her to look at him.

"You look at me," he orders, and a growl underlays his words. It makes him sound inhuman.

It also makes Molly whimper and list forward, hands pressing against his chest to keep upright. Sherlock's nostrils flare, and his mouth twists in a dark approximation of a smile before he leans his head down. He nips at her ear, all wet, sharp teeth, and Molly jumps.

"Pray you make it back to Baker Street before I do, Molly," he whispers huskily. "It'll go twice as hard on you if I have to wait."

He steps away, and Molly staggers. He even nods to Denise, who waves cheerfully.

"Nice to meet you," Denise calls, "I look forward to our first family dinner."

Sherlock quirks an eyebrow at her, shifts one hot, lingering look onto Molly, and then turns on his heel. He strides away, quite soon disappearing around the corner.

"Oh, yeah, if you guys Bond. Whatever. Look out, you're going to wake up and he's going to be tattooing his name on your arse." Chortling, Denise appears satisfied. "I have to say, I was worried at first, but seeing that... well. Don't worry, Molls, it's the usual fun and games between every Alpha and Omega."

"Yeah, um, what?" Blinking herself back into focus, Molly turns hazy eyes to Denise. "I uh...I need to go. I'll see you... later."

Flagging down a cab takes a completely stupid amount of time. Sherlock had a head start – he's got to be at least half way to Baker Street. Molly fusses worriedly in the back, chewing on the inside of her lip and very nearly shrieking with frustration when she's taken into a truly spectacular traffic jam.

"Are you kidding me?" she hisses. Digging money out of her purse, she tosses it into the front seat.

"Miss – miss, what are you –"

"Too slow," she snaps at the driver, shoving her way out of the taxi and into standstill traffic. She hoists her purse across her body, hooks a shopping bag apiece over her wrists, and darts for the sidewalk. Once there she thinks hard, trying to remember the side streets and alleys Sherlock knows so well.

She's fairly certain if she cuts through this alley she'll hit a side street that ends not far from Baker Street. And she may even beat Sherlock back, or at least meet him there. It's better than nothing, and she darts onto the side street at a jog, bags bumping her legs as she runs.

It happens so quickly, Molly doesn't even have time to shriek. Hands at her shoulder, her waist, a strong body coming at her from an alcove. Yanked off balance, Molly is dragged backwards until she hits a brick wall, lungs filling with the scent of Sherlock, lust, and – unfortunately – the reek of a nearby dumpster.

"You knew I'd hit the traffic and get out and run," she heaves accusingly, trying to slow the race of her heartbeat. Sherlock's mouth is at her neck, now, and she can feel him smiling there.

"Yes," he agrees, hands pushing her light fall jacket to the side. He palms her sides, her hips, seems content to press her against the wall and simply fill his hands with her. Molly tips her head back, eyes closed as she breathes deeply, dizzy from how good it feels.

They're still going to have to work on boundaries. But after the Bonding. She misses him too much when they're apart, and she doesn't like giving up time that they could be spending together.

Of course, it doesn't mean she's going to make things easy on him.

Gripping the handles of her bag below where they are hooked on her wrist, she hits Sherlock on the hip with it. Hard enough to make him grunt and stumble, to make him snarl against her neck before his head pops up and he's glaring. Molly grins, slipping out of his loosened grasp and taking off at a dead run.

It's freeing, bolting through London with Sherlock hot on her trail. Chest heaving, heart pounding, knowing she's either going to get caught or will weed out an unworthy Alpha. Not that it's even a possibility; between his long stride and determination, Molly knows he's going to catch her.

But not at once. He stays far enough behind to let her keep moving, but close enough to brush his fingers through her hair when she skids around a corner. Sherlock laughs – a surprising sound, one that makes Molly laugh as well, and then whoop, and suddenly they're breaking onto a busy street and darting through a small crowd.

They don't stop running.

A few give them knowing looks. One man hoots, tossing Molly a thumbs up. "Have fun, little sister!" he calls, and Molly catches the scent of Omega from him as they pass.

Thank God the others can smell it, or the average people would be calling the police.

A stitch in her side makes Molly stumble, and Sherlock is quick to catch her. He hauls her tight against him, chest heaving at her back. The shopping bags she carries bump both their legs. Laughing again, he gives Molly a squeeze.

"I've caught you," he says, voice thick with smug approval.

A thrill of ecstatic, delirious joy hits Molly so hard her knees nearly give out. She wants to laugh, to kiss Sherlock, to have his weight on her, to fall asleep together – and to spend a life with him. "Yes," she agrees, caught between breathless laughter and tears, "fair and square."

-X-

Sherlock almost doesn't answer his mobile when she calls. But Molly has set a picture of herself to pop up when she calls, one with her glasses sliding down her nose and a big, happy smile curling her mouth. He's become conditioned to give into that smile (to the woman in general, even if he won't admit it). And if she wants to speak to him, even while he's on a case, well... he can at least bark an I'm busy before hanging up.

Standing over the corpse that makes this area a murder scene, Sherlock answers the call. "Molly," he says in greeting, now drawing a breath to inform her exactly how busy he is. However, before he can achieve the words Molly is cutting him off, a pained sob leaving her throat.

"Sherlock, help," she gasps. It sounds as though someone has taken a knife to her gut.

He goes cold. Someone has harmed Molly. Wounded her? Seriously, perhaps? Is it a kidnapping? A warning to him, a grudge against her, a random attack...?

"It's come early," she's saying, and though he's clinging to her words with the full force of his magnificent focus at first he doesn't comprehend. "My heat – it's come early, I'm burning up –" More tears.

A split second later, he understands... and it is like being hit by a bolt of lightning. Gut tightening painfully, Sherlock's free hand clenches into a tight fist. He turns sharply away from the busy crime scene, moving away. John is following him, waving his hands and mouthing, What's wrong? Is Molly okay? What's wrong?

Focus. Molly needs him: in her state, it's a wonder she had enough presence of mind to call. "Where are you?"

"Work." A heavy thump – a door. Very faintly, the rush of air over the receiver.

"Are you in the cold storage freezer?" he asks, eyes narrowing.

"I'm burning up!" she comes close to shouting, and maybe it's only Sherlock's imagination (surely his hearing isn't this acute), but he swears he can hear threads straining as Molly fights to rid herself of autumn layers.

"I'll fetch you. Just wait there, Molly."

"Please – Sherlock, it hurts so bad, I'm so empty –"

A moment of static and white noise across his brain. The muscles in his thighs are jumping with the effort it takes not simply break into a run. "Of course you are in pain, it is a natural course of the symptoms. Given how quickly and early this came on, and the fact that you have not had a heat since your first, undoubtedly this one will be... severe. I will be there momentarily, Molly."

"Hurry, Sherlock. Please."

Ending the call, Sherlock shoves his mobile into a coat pocket. He breathes deeply and slowly, working hard to maintain rationality. Molly needs him to be strong for her, as she's obviously overcome by her heat. There will be time enough to lose himself once they are behind closed doors – but until then, he must remain in control.

"Oh boy," breathes John, eyes going wide as he backs away. "That was not what I was expecting. This is... awkward. For me. I'll just stand... over there. Away from.. this." Gesturing widely at a glowering Sherlock, the veteran scampers away. Honestly, for all he encouraged Sherlock to enter into a sexual relationship with Molly, he is absolutely skittish when it comes to anything having to do with the Alpha/Omega dynamic between the two.

"Oi – where do you think you're going? We've got a body here, Sherlock –" Of course Lestrade catches Sherlock on his way out.

Waving him off irritably, Sherlock doesn't stop walking – forcing the DI to break into a jog to catch up with him. "One you will be handling on your own, I'm afraid. Something has come up."

"What? Something has come up – what's more important than a bloody murder to you?"

"Molly," John provides, catching up with them both. "She's got a... thing. That she needs help with."

"A thing?" repeats Lestrade dubiously.

At the edge of the street now, Sherlock waves down a cab. He irritably snaps over his shoulder, "She's gone into heat. I'll be unavailable for the next week." Wrenching the cab door open, he provides the driver with his destination while sliding inside. It pulls away before Lestrade can summon up the sense to respond to the announcement.

Firing texts off to Mycroft, Sherlock grits his teeth as he calls in a favor. He can't put Molly in a cab – what if the driver is an Alpha, or even a Beta? Mycroft quickly agrees to provide a car with a discreet neutral driver, and Sherlock is grateful, though he won't be telling his brother this any time soon. If ever.

Time passes at an enraging pace, minutes seeming to stretch into hours. Nervous energy has taken over Sherlock's body, leaving his hands and feet to tap and twitch in odd, uncontrollable convulsions. Waiting for Molly's heat seemed torturous, but now he wonders if it would have been better to prolong the time before she went off her suppressants. Their relationship is terribly new, and the knowledge that Bonding is practically assured will set them at a level far above what Sherlock thought of having.

These fears are easy to push away, however, and Sherlock locks them in a dusty cupboard in his mind palace. His worries over Molly are far more substantial and taxing, egging on a fierceness that can only be displayed by an Alpha who believes his Omega is under threat. It would be shockingly easy for any Alpha to be overcome by the scent of her heat and take advantage of her, or even a Beta. Reports of rape when Omegas go into heat are not uncommon: a body may be willing, but it does not mean the mind is.

Sherlock doesn't wait for the cab to come to a complete stop before pushing the door open and jumping out. By this time he has texted Mike Stamford, and Molly's superior should be arriving at the morgue anytime to take over. While he cannot perform autopsies he can run the morgue for a while. Chucking money through the driver's open window, Sherlock dashes across the sidewalk to a side entrance of St. Bart's.

Upon entering the morgue lab, Sherlock is overwhelmed by the scent of Molly's heat. It has saturated the air so thickly that it has a taste: thick, musky, and bittersweet. At his side, Sherlock's hands curl into tight fists. Endorphins, hormones, and adrenalin flood his brain and nervous system. The primitive little gland that makes an Alpha an Alpha goes on high alert, flooding Sherlock with the instincts and urges more suited to animals than men.

A noise draws his attention. Scenting the air, Sherlock finds an abrasive stench mingling with Molly's intoxicating one.

Doubled over on a stool, arms around his stomach as though he is attempting to hold himself back, is a young man. One of Molly's residents, studying to becoming a pathologist. His name is Wilson: he recently ended a long term relationship, is the owner of two large dogs and at least one cat, and he seems to be allergic to peanuts. Boring, Sherlock had decided upon their first meeting, and promptly ignored the nervous young man every time he came into the lab or morgue while Sherlock was working. Unless he'd needed coffee, of course.

Today is an entirely different situation, however. Betas are rare and unique, as they are both Alpha and Omega. Their heats are triggered either by an Alpha's pheromones or an Omega's heat: and right now, this... Wilson... is as much affected by Molly as Sherlock is.

"Get out," Sherlock snarls, taking a threatening step forward. His fists are white knuckled. The urge to attack the Beta is nearly crippling, and the restraint he shows now will not last very much longer.

"She smells so good," Wilson whimpers. His face glistens with sweat. "I don't – I don't even care for Dr. Hooper that way – but the scent –" Cutting himself off with a groan, the resident lifts his hands to hide his face. Staggering as he slips off the stool, he slowly moves towards the door to the actual morgue.

Of course Molly chooses this moment to make her appearance. She's shed several layers, and is now wearing an old vest and baggy shorts Sherlock knows she keeps handy for early morning work-outs in the Bart's gym. Her hair is messily pulled up in a make-shift bun, though several stands have fallen free. They stick to her face and neck, and she practically shimmers with the heat waves coming off her body.

"Sherlock..." Molly radiates relief when she sees Sherlock. Unsteadily she moves forward.

It is here that Wilson makes a near fatal error: he reaches out for Molly. A hand wraps around her upper arm, pulling her to a stop. She tries to tug out of his grip, but the first rush of her heat has left her weak.

Sherlock moves so quickly the lab briefly becomes a blur. Wilson screams as his hand is bent backward, wavering as though he may collapse.

"Touch her again and I'll rip out your throat." This threat is issued with a quiet intensity that clearly speaks to Sherlock's willingness to follow through with it.

"Sherlock! Sherlock, no – don't –" Despite Molly's weak pleadings, she is clearly aroused by his actions. Omega biology makes this unsurprising: no doubt seeing her Alpha of choice physically overpowering a potential rival solidifies his capabilities as a strong protector and provider. Though she takes hold of his arm, her grip is loose and easily shaken off.

Instincts screaming, Sherlock drops Wilson's (now broken) wrist to turn on his Omega. He peruses her with sight and scent. Walking slow circles around her, he watches as Molly continually lists towards him, skin prickling as though she can feel his gaze where ever it lands. Her scent rises; Sherlock inhales a deep lungful, a low noise of appreciation leaving his throat.

Logic fights its way through primitive urges. "I've ordered a private car," he announces, pausing behind her. Brushing wisps of hair from the back of her neck, Sherlock bends. Running his nose over the soft flesh, where there is a heavy concentration of scent makes both he and Molly moan. He has to take a grip on her hips to keep her upright. "It should be waiting."

"We should go, then." And yet Molly does not move to leave. Instead she backs up, pressing against Sherlock as tightly as she can. Her head turns, nuzzling against his chest. "You feel so good. I should have known this was coming... I dreamed of you, last night. All night. I woke up so wet, and I was late for work because I was too busy fingering myself to get –"

Pulling Molly around to face him, Sherlock cuts her off with a kiss. She strains into him, pushing her hands under his Belstaff and suit jacket to tug fitfully at his shirt. Little noises of distress well up in her throat, and before Sherlock can even think about stopping her, Molly is pulling the tails of his shirt from his trousers. Too soon she is palming his stomach with both hands, a sigh passing her lips to breach his own, filling him with her need.

An air horn screams through the lab morgue. Sherlock breaks away from Molly with a snarl, settling a hateful glare on Stamford. He holds the air horn in front of him in the manner of a weapon. The expression lain across his features is one that appears torn between exasperation and amusement.

"Break it up," he chides mildly. "A driver called reception, a car has arrived for you. Go on, get out of here."

Sherlock finds it within himself to nod, though he tightens the arm wrapped around Molly's waist. The thought of space between them in their present conditions makes him feel terribly violent, and given he has already broken one man's wrist today – "Wilson will need looking after," he informs Stamford while allowing Molly to pull him into a brisk walk.

"What? Why – oh my God, Wilson, what happened?"

"Nothing," the resident attempts to lie, hissing out through his teeth when Stamford rushes forward to begin looking his wrist over. "Just – just the usual. I'm a Beta, sir, and... Dr. Hooper's heat..."

Whatever Stamford's response may be, it is lost to Sherlock when the lab door falls shut behind he and Molly.