It's barely light outside, still too early to wake up for school, but Mei's eyes fly open from a dead sleep. Staring up at the ceiling, her pupils dilate until the amethyst irises recede to thin rings.

Good god, what is that smell?

Assaulting Mei's nose was the most delicious, sweet aroma. A mellow flowery scent— jasmine, with bright citrus notes. Like walking through an orange grove on a perfect summer day. Like laying naked beside your lover in a field of wildflowers under an endless blue sky.

Mei closed her eyes and inhaled deeply, the scent coiling around her brain, intoxicating. It smells amaze. The scent, unquestionably feminine, was also potently sensual, and it communicated a clear, ringing imperative. She felt a familiar tingle spark to life between her legs.

Along with the aroma wafting from beside Mei, was a soft whimpering sound.

Realization struck Mei like a thunderbolt. Like a sack of goddamn bricks dropped on her head.

"Yuzu, you're in heat!" Mei screamed, leaping out of the covers as if the bed was made of lava.

Yuzu slowly lifted her head to turn and gaze at Mei. The blonde was on her stomach, hands fisting the sheets beside her head. Her eyes were rimmed red and a light sheen of sweat was glistening on her forehead. She looked like she wanted to respond to Mei but she suddenly closed her eyes tight, dropping her head onto her pillow again.

Despite the warmth that radiated from their bed, Mei's blood ran cold. "Yuzu, you're…you're an Omega?" the younger girl whispered.

Yuzu could only respond with a pitiful groan.

Confusion, panic and dread gripped Mei as her brain scrambled to digest all the things she discovered upon waking up a few seconds ago. She took a deep breath – big mistake, because Yuzu smelled like a fucking snack – and stated, "You are an Omega. And you are in heat."

"Yes thank you, Captain Obvious," Yuzu replied, wanting it to sound snarky but it came out all breathless instead.

"But you're a Beta!" Mei cried. "How could you have failed to mention that you're actually an Omega?"

In the back of her mind, she knew that she was overreacting, at least by accusing Yuzu of keeping it a secret. Having gotten perfect grades in Anatomy, and every other subject for that matter, she knew full well that females will usually present as an Omega between 15 and 17 years of age, precipitated by their first heat. At 18, Yuzu is a little late, but still within the normal range for healthy female Omegas.

"Mei, listen," Yuzu said with a weary sigh. "I don't feel good." She closed her eyes and swallowed. She raised her arm weakly towards Mei and beckoned. "Can you come here please?"

Mei was already backing away slowly from the bed. "No, Yuzu. I can't," Mei said firmly. "I shouldn't even be here."

Yuzu struggled a little bit before she was able to pull herself up on her elbows and look at her sister. Mei felt her heart kickstart when Yuzu leveled her with an intense gaze. The muscle triphammered painfully in her chest. Her retreat from the bed was halted as Yuzu's gaze rooted her to the spot.

Yuzu spoke again, but this time the pressure behind her words was practically tangible. "Mei. I need you. Come here, please."

Each inflection of Yuzu's voice was like a gentle tug at Mei's core, compelling her to come closer to her stepsister. The air in the room shifted, and a new layer settled over the pervading scent: desire.

A chill skittered up the length of Mei's spine as she struggled with the urge to stride over to the bed and and give her stepsister all the help she needed, and then some.

Mei turned on her heels and fled the bedroom.

Mei had already been in school for 2 hours by the time the first students started showing up for the school day. She went straight to Aihara Academy after hurriedly leaving the apartment earlier that morning. Sitting in the Student Council Room, she was able to calm down and pull herself together.

First, she needed to get a hold of their mother. Ume hadn't been home for a few days because she was doing double shifts at the construction site this week. Mei tried calling her several times, finally leaving a voicemail explaining Yuzu's 'situation' and that she should come home straight away. Yuzu needed pills or given the hormone suppression shot, or something.

Next, come to terms with this totally unexpected discovery about Yuzu, and what that means to their already tenuous relationship. Just a few days ago they finally reached an uneasy truce, agreeing to start being nicer to each other. Mei agreed to stop being so judgmental over Yuzu being a delinquent and a gyaru, and Yuzu agreed to stop calling her a robot with a Yamato Nadeshiko complex. Mei was so relieved that they were finally going to have a normal, non-combative relationship, because living with their antagonistic dynamic was fraying her nerves. But now – Yuzu is a goddamn Omega. Mei groaned, putting her face in her hands.

Mei was suddenly yanked out of her brooding thoughts when she sensed something. Her spine snapped up straight and she cocked her head. It was faint, but the pull was unmistakable. Fuck. No, no, no.

Mei rushed out of the room and broke into a run down the hallway. As student council president, she would have upbraided anyone running in the halls as fast as she was, but she couldn't give a flying fuck right now; she could only follow her instinct down these corridors.

Mei found Yuzu by the shoe locker area near the main doors. Her stepsister was leaning against the lockers, her blond hair uncharacteristically tousled. Yuzu never left their apartment without styling her long blonde hair and making sure it was on point. Having confirmed that Yuzu was indeed here in school, Mei almost howled with frustration.

What are you doing here, you idiot, how are you so stupid I'm going to kill youuu

The anger was immediately replaced by a cold fear that clawed in her chest. Yuzu was an unclaimed Omega in heat, and she was out here in public. Just chilling like it was a goddamn stroll in the park. Surely, surely Yuzu knew that Omegas in heat don't go out in crowded places, and if they absolutely had to, they were with their Alpha. Mei felt like banging her head against the nearest wall. Why was she always so reckless? Why was she here? She didn't even like school.

Mei quickly counted the number of known Alphas in the student body. Mentally flipping through all the students in a matter of seconds, she catalogued each face as Alpha, Beta, and Omega. There were 19 Alphas in the school. 19 Alphas in the vicinity who could smell an Omega in heat. 19 teenage girls compelled to claim the Omega and become her Alpha.

Only a few seconds after Mei committed to memory all the Alphas in the school, did she sense the nearest one in Yuzu's immediate vicinity.

Mizusawa Matsuri.

From across the atrium, Mei watched Matsuri lean towards Yuzu and say something in her ear. The pink-haired girl was smiling as she lightly squeezed Yuzu's upper arm, but Mei knew that her intentions were anything but innocent. At the very least, that little shit was trying to get a nice good whiff of Yuzu's heat.

Mei was gripping Matsuri's wrist and twisting it off of Yuzu's arm with a kotegaeshi wrist lock before the pink-haired girl could finish the thought she was trying to tell Yuzu. Matsuri's eyes widened in surprise at seeing Mei appear beside her like a motherfucking wizard. She yanked her hand out of Mei's grip and snapped, "What's your deal? Yuzu and I are having a conversation."

Mei stepped towards Matsuri, intentionally invading her personal space. She let a low growl reverberate in her chest. "Your conversation with Yuzu is over."

The two girls stared each other down until Matsuri looked away, knitted her brow, and bared her neck at Mei. She stood like that, head cocked to the right to expose her neck, clenching her jaw, until Mei turned away from her. Matsuri snatched her bag from the floor, muttered "Has no fucking chill," and walked off in a huff.

With difficulty, Mei resisted the strong urge to lean towards Yuzu, trail her own nose up the long delicate column of the blonde's neck, nuzzle into the scent gland just below the ear, close her eyes, and inhale deeply. She couldn't because she just bit off Matsuri's head for trying to be slick and do the same thing. Dammit Matsuri!

She glared at her stepsister and said in a tight voice, "Students in heat are supposed to stay at home. Omegas don't leave their houses during their heat because it's dangerous. Especially during their first heat."

Yuzu, still slumped against the locker gritted, "I came because," and winced in pain, "I didn't want to be all alone, and I need—"

"You never bother to follow the rules," Mei snapped. "If you want to come to this school, you need to abide by its regulations!"

Yuzu balled her fists and looked like she might cry from frustration. Their old conflicts once again came to the fore, but she really didn't need this shite right now. Now more than ever she wanted to tell Mei where to shove her perfect, rule-abiding persona.

"Screw your rules. I do what I want!"

As Mei had predicted, sitting in class with an Omega in heat sucked ass. Yuzu's scent got progressively stronger as each hour went by, so by the last class before lunch Mei could barely think straight.

Mei couldn't draw a full breath of air into her lungs without snorting a hit of Yuzu-laced pheromones. Yuzu's scent hung so thick in the room, Mei could taste it in the back of her throat. It was impossible to escape from it, because it was in the fucking air.

Mei looked up at the chalkboard and squinted at the algebra problem, trying to make sense of the numbers and letters. But it was kind of hard to concentrate when the scent was making her stomach hurt, her head throb, and her core temperature rise to dangerous levels. For the fourth time that morning, she took out her handkerchief and wiped the sweat that was forming on her hairline.

She looked at the pencil she was gripping in her hand and imagined stabbing herself in the eye with it. She silently begged for any excuse right now to leave this room. But she was bound to her desk by duty, responsibility, and convention. She was Aihara Mei, and Aihara Mei obediently sat through class even if her hair was on fire.

Through the fog in her brain she heard the sensei's voice asking, "Aihara-san, what is our ordered pair?"

Mei's heart leapt into her throat, because she had no fucking clue what the answer was. And this never happened. She had never been distracted during class before, never in her whole glorious academic career.

She was about to fake a coughing fit or a seizure or something when she heard Yuzu's voice behind her say grumpily, "I'm sorry but I don't know sensei."

Mei's shoulders sagged in relief when she realized the sensei was addressing the other Aihara in the room. She fought with all the pathetic will she had left, but she found herself turning around to look at Yuzu who sat four rows behind her. Her breath caught in her throat when she saw Yuzu staring right at her, with the intensity of a thousand suns. Jesus!

Mei observed that Yuzu's fingers were curled against her desk, her perfectly manicured (and in violation of school rules) fingernails pressed into the wood. Her breathing was shallow, and Mei could practically hear her erratic heartbeat.

In a distant part of her mind Mei knew she looked a little strange turned around in her seat in the middle of class, just dead ass staring at Yuzu, transfixed. But she couldn't tear her eyeballs away from Yuzu's mouth when the blonde very delicately bit the side of her lower lip and lifted her chest with a deep breath, and still with that smoldering stare. Yuzu's teeth pressed down on her lip, hard, drawing red to the surface of the flesh.

That sight of Yuzu's tender flesh caught between teeth triggered something primal inside Mei. Her face sliced into a feral smile, teeth bared and eyes glinting with promised violence. Her muscles went taught, anticipation thrummed in her body, her vision tinged red, and she had the urge to leap out of her chair and tackle her stepsister. They were on the ground, Yuzu pinned under her, she was going to take care of that little problem with her heat. First she was going to take that bottom lip in her mouth and tug on it. Mine.

Stop it, brain!

With a supreme effort of will, Mei turned back around to face the front of the classroom. Her eyes landed on Inukai Isuke, sitting in the front corner of the room, also turned around in her seat and unabashedly staring at Yuzu. The Alpha clearly gave zero fucks if people realized that she was thirsting for an Omega who was in heat. On any given day Isuke slept through most of class, so seeing her upright and attentive was disconcerting to say the least. She was leaning forward towards Yuzu's direction, heels raised from the floor, looking like a cat ready to pounce.

Mei sighed. It was going to be a long, painful day. Dammit, Yuzu.

When the bell rang for the lunch break, Mei shoved her things into her bag and hurried out, thankful to finally escape the suffocating room. She ignored students trying to talk to her and get her attention as she walked quickly to the Chairman's office. She pulled out the key from her pocket and unlocked the door. The brunette stepped behind the mahogany desk and stood in front of the massive display case that contained dusty old books, antique pottery, awards, and Aihara family heirlooms.

She grabbed the katana that had been in her family since the Edo period.

She followed Yuzu's scent to the courtyard in the middle of the building. Sighing in relief that she could see the blonde standing upright on her own two legs, not pinned under anyone or shoved up against a wall or mounted like a –

Yuzu's eyes lit up when she turned and found Mei standing beside her. She reached for Mei's arm and tugged on it, reflexively, as if she couldn't help it. Yuzu hung on to her arm and looked at her with big doe eyes. "Mei," Yuzu said in a whine, "don't leave again, c'mon."

"Yuzu, I told you. You need to go home. Please just do what I say, just this once."

The blonde responded to that with a frustrated mewl and by fisting the front of Mei's shirt with her other hand. She tugged Mei closer until their faces were less than a foot away from each other. She whined again, "No, I'm staying here with you! Why can't we just, like, talk for a minute, come here…"

"Let go of my shirt please," Mei said as she pried Yuzu's hands off her. "How would you like it if I was crumpling your clothes while you were wearing them?" Then she tried to swat Yuzu's hands away because the blonde started to get handsy with her. Pawing like a goddamn cat.

"I'm not crumpling your clothes, geez…"

Mei didn't have to turn around to know that there were several Alphas now standing behind her. She felt them approach with deliberate and measured steps. Right away she recognized most of the girls' energy signatures; she had expected them after all. Their scents were all enhanced with higher than normal levels of adrenaline and testosterone.

Yuzu's eyes widened when the group of Alphas shifted into her line of sight. Usually an unmated Omega feels drawn to any Alpha in their vicinity when in heat, but not when they were in a fucking pack and being very threatening and intimidating with their smells and posturing and shit. Yuzu willed her body not to tremble and resisted the urge to tuck her head into Mei's neck and screw her eyes shut.

Mei slowly turned in place, keeping herself between Yuzu and the Alphas. She stared at five apex predators standing in the middle of the courtyard, drawn here by Yuzu's scent.

As packmaster, Azuma Tokaku stood in front of the group. Tokaku was a taciturn girl with a misanthropic streak, and so Mei was kind of surprised that she was packmaster, out here being a "leader" to these girls. But obviously, it was because no one could beat her in a fight.

Tokaku was flanked by Inukai Isuke on her right and Sagae Haruki on her left. Behind them, Takechi Otoya and Hanabusa Sumireko.

"Aihara-san. We want to have a word with the Omega," Tokaku said, throwing down the challenge with her words.

Behind her, Isuke's lips curled into a smirk. Her body was canted to one hip, cutting an imposing figure with her tall, lean body, which Mei knew was lethal and very dangerous. Her eyes were locked on Yuzu, and she ran the tip of her tongue along the edge of the upper row of her teeth. Mei rolled her eyes. Isuke was sexy as hell and criminally gorgeous, but sometimes she was a bit much.

"No. Stay away from her," Mei said evenly. "She's not for lunch."

"The hell she's not," Tokaku snarled. Her pupils contracted to pinpoints, the ice blue chips making her look feral and rabid. Mei wouldn't have been surprised if they started fucking glowing.

Mei knew she had seconds until shit got real. She assessed the rest of the Alphas quickly.

Haruki – a nice girl really, a conscientious student, and Isuke's girlfriend. Freakishly strong. Sumireko – heiress to one of the richest families in Japan, very prim and proper. No doubt hiding some kind of crazy superpower/skill/quirk something. Otoya – on the outset she was pretty, polite, and pleasant. But there was something seriously off-kilter about her. And she smelled like spilled blood and torture. She had a Cheshire cat grin on her face and looked completely unhinged.

Mei swept her gaze around the courtyard, taking in the position of the trees, the square footage of the open spaces, the concrete structures, the uneven surfaces. She was no brawler, but ever since she woke up this morning she's had to constantly make adjustments to her damn life. Let's add a lunchtime battle royale to the list, because why fucking not?

She turned around and looked at Harumin straight in the eye. Imbuing her voice with authority, she said, "Take Yuzu home now. Find my grandfather's driver in the front office and have him drive her home."

As a Beta, Harumin was compelled by instinct to obey this direct command. Harumi grabbed Yuzu's wrist and dragged the blonde away. She must have been really forceful, because there seemed to be a residual effect on Nene, who also scampered away and was shoving Yuzu along.

Mei faced the pack of Alphas. Mei knew that this won't go down as easily as it did with Matsuri. Not by a long shot. No, these five were the biggest and the baddest.

Tokaku flicked her wrist and sunlight glinted on the the three sharp blades sticking out between the fingers of her closed fist. Like she's goddamn Wolverine.

Mei curled her hand around the handle of her sword and waited for Tokaku to make the first strike.

Mei entered the apartment and slipped off her shoes in the entrance hallway. She winced when she had to bend her torso, but luckily no ribs felt broken. Her knees were scraped and there was a gash on her forehead. But no one had followed her home. She made sure they weren't in any condition to.

She stepped into the kitchen and opened the freezer for ice to put on her face. She already felt the bruise forming. She just wanted to forget how she was Sakura Punched into a concrete planter by Hanabusa Sumireko.

She padded around the apartment looking for signs of Ume but found that their mother wasn't home. Her phone must have died again and never got her messages. For fuck's sake. She loved that woman, but for real, get it together.

Mei stood in front of the door of the bedroom. She knew that she should turn away. Go stay in her father's or grandfather's house for the next few days. After a long time, she turned the doorknob and pushed the door open.

As Mei stepped in the room and inhaled, she tasted Yuzu's essence, distilled on her tongue. The composition of the smell was the same one she encountered this morning when she first woke up, but scent had matured into something earthier, muskier. Warmth spread through her whole body, to the tips of her toes to the top of her head.

Adding to the sensory overload was the sight of her sister. Yuzu was laying on her stomach under the sheets, with just her head sticking out. By the way the sheets rustled, it was clear that Yuzu's hand was between her legs, working furiously.

Yuzu slowly opened her eyes and looked at Mei standing in front of her. Her eyes were wild and unfocused, and she had the look of someone who had been dancing on the razor's edge for hours.

It took Yuzu a few moments to say, "You're hurt."

Mei shrugged. "I'll live. You should've seen the other guy."

"My hero," Yuzu purred.

I guess you're going to continue to masturbate while we have this conversation. Cool cool.

"This isn't a joke. Do you even realize what could have happened?" Mei said, frustrated that the blonde didn't seem to grasp the situation. "A whole fucking pack, Yuzu. That was seriously the dumbest thing you've done yet."

Yuzu's eyes flashed at that little dig. She stopped her ministrations between her legs and lifted herself up on both elbows. The blonde narrowed her eyes at her stepsister.

"There was no way that you could have gone though the day without getting jumped. What the hell were you thinking?" Mei hissed.

Yuzu slowly rose. The pile of sheets fell away from her as she slipped off the side of the bed.

Mei's heart stopped when Yuzu stood up to face her, completely naked. Her eyes widened as she took in her stepsister's bare body. Her breasts were heavy, fuller than when she had last seen them in the bath several months ago. Her nipples were hard, the color of crushed pink rose petals. Mei was sure they were begging her to take them in her mouth. Mei's eyes traveled farther down, to the graceful curve of her waist and the flare of her hips. Soft dark curls on the apex of Yuzu's thighs. Mei saw that it was wet with arousal.

The sight almost brought Mei to her knees.

Giving Mei a sultry look, Yuzu said, "I came to school because I needed you."

Yuzu's voice was silky and seductive. Yuzu's voice, along with the scent rolling off of her, were like velvet tendrils that wrapped itself around Mei.

"Alpha," Yuzu said with hooded eyes and an indulgent smile on her lips.

The word reached out towards Mei, between her legs, and fucking stroked. Like, it slipped two fingers in and moved them up and down gently, maddeningly. Fuuck.

Clearly Yuzu knew the effect the word had on Mei because she said it again.

"My Alpha."

Mei's whole midsection clenched, and arousal pooled in her pelvic floor, like warm molasses.

And like a scene ripped out of Mei's fever dreams, Yuzu closed the distance between them.

Author's Notes:

For the uninitiated, Alpha/Beta/Omega dynamics or aka Omegaverse, is a fanfiction trope that explores power dynamics within a hierarchal system based on animal behavior. In this alternate universe, people are born as either an Alpha, Beta, or Omega. Fanfiction writers usually choose from elements like mating, bonding, scenting, heat / rut , knotting, breeding, werewolves, dominance, submission, etc. If you really want to nerd out: omegaverse originated in the Supernatural fandom.

The girls from the "pack" are from Akuma no Riddle, one of the best yuri mangas EVAR, in my opinion. 12 girl assassins participate in a killing game in a high school called Myojo Academy. There are not just one, but THREE (maybe four?) canon lesbian relationships.

I titled this piece "My Sister's Alpha" as a play on the phrase "my brother's keeper" What do you guys think of this story? I'd love to hear your thoughts on it! I couldn't resist putting in a little bit of shonen, you like? And Mei as a sword lesbian is one of my greatest kinks, lol.