A New Set

The first day of the new school year at Inarizaki High started like any other. The boys' volleyball team shuffled into the locker room, half-asleep, yawning, reaching for their practice jerseys. Suna Rintarou leaned against a locker, scrolling through his phone with his usual bored expression. Ginjima Hitoshi was fighting with his knee braces. The libero, Michinari Akagi, was already fully dressed, bouncing on his heels like he'd had three coffees too many.

Then Atsumu Miya walked in.

Not the Atsumu they'd always known—tall, sharp-jawed, voice that could cut glass, ego that could fill the whole gym. No. This was Atsumu with longer hair, a softer face, and wearing the girls' uniform.

Dead silence.

Atsumu dropped her bag on the bench and looked around with that same challenging smirk. "What? Never seen a girl before?"

Ginjima's mouth opened, closed, opened again. "Uh. Miya? What—"

"I'm a girl," Atsumu said flatly, like it was the most obvious thing in the world. "Been one for a while, actually. Just figured I'd start the year off right. Got a problem?"

Three seconds of nothing. Then Suna let out a low hum. "Makes sense, honestly. You've always had more dramatic energy than the rest of us combined."

"Oi!" Atsumu snapped, but there was no heat in it.

Coach Kurosu poked his head in to see what the hold-up was. He just shrugged. "Miya. Long as you can still set, I don't care if you're a girl, a guy, or a talking octopus. Get dressed. Practice starts in ten."

And that was that.

The team moved on. A few polite questions—pronouns (she/her), name (still Atsumu, thanks), should they call her anything different (no). Within the hour, she was just Atsumu again. Same insufferable, brilliant setter she'd always been, only now with a skirt and a ponytail.

The only person who couldn't seem to move on was her twin brother.

Osamu stood frozen by the door for a full thirty seconds after Atsumu announced herself. His gym bag slipped from his fingers and hit the floor with a soft thud. His face cycled through about fifteen expressions before settling on something between confusion and mild panic.

"Tsumu?" His voice cracked in a way it hadn't since middle school.

"Samu." Atsumu's smirk softened, just a fraction. "I know it's a lot. We can talk later, yeah?"

Osamu nodded mechanically, then bent down to pick up his bag. He didn't say another word for the rest of practice. He just watched his sister—his sister—move through drills with the same fluid grace, setting balls with deadly precision, barking orders at their teammates, grinning that insufferable grin when she pulled off something impossible.

She was the same. She was different. She was his twin, but she was a girl now, and Osamu's brain couldn't reconcile the two.

---

The first week was rough. He caught himself reaching for Atsumu's shoulder to roughhouse, then pulling back at the last second like she'd burn him. He stopped calling her an idiot to her face. Started opening doors for her. Offered to carry her bag.

Atsumu noticed. Of course she noticed. They were twins—she could read him better than anyone.

"Samu, I swear to god, if you try to pull out my chair for me one more time, I'm gonna hit you with a volleyball at full power."

"I'm just bein' polite," he muttered, shoving his hands in his pockets.

"You're bein' weird. I'm still me. I can open my own damn doors."

But Osamu couldn't help it. Some primal, protective instinct had kicked in the moment Atsumu came out, and it refused to shut off. He walked her to class. He glared at anyone who looked at her funny. He even tried to walk her home, which was absurd because they lived in the same house and had walked the same route together for sixteen years.

"You're smotherin' me," Atsumu complained one evening, shoving a spoonful of rice into her mouth. "I can't breathe without you hoverin'."

"M'not hoverin'."

"You literally stood outside the bathroom for fifteen minutes while I was showerin'." Atsumu fixed him with a flat stare. "Ma called the police, Samu. She thought there was a stalker."

Osamu's ears went red. "I was just... makin' sure you were okay."

"I was in the shower. How would I not be okay? Did you think the water pressure was gonna attack me?"

The worst part, Osamu thought privately, was that he couldn't even articulate why he was acting this way. It wasn't that he didn't accept Atsumu—he did, completely, without question. She was his twin, his other half, the annoying voice in his head that never shut up. That hadn't changed.

But something had shifted. Atsumu had always been his rival, his equal, the person he fought with and fought for in equal measure. Now she was also his sister, and that word carried a weight he didn't know how to handle.

He wanted to protect her. Wanted to be gentle with her. And Atsumu, predictably, wanted absolutely none of that.

---

Three months into estrogen treatment, the changes became impossible to ignore.

Atsumu's face softened first—jaw less sharp, cheeks fuller, skin clearer than it had ever been. Her voice didn't change much, still carried that raspy, teasing edge, but there was a new warmth to it that made people listen closer. Her hips widened. Her waist cinched.

And then there were the breasts.

Not huge—Atsumu was tall and lean, her build didn't lend itself to an ample chest—but they were there, noticeable under her jersey in a way that made Osamu's brain short-circuit every single time.

The first time he saw her in a sports bra during practice, he dropped a full bottle of water on his foot and didn't even feel it.

"Samu, you okay?" Atsumu asked, a wicked grin spreading across her face. "You look a little pale."

"Fine," he choked out. "M'fine. Gotta go."

He did not, in fact, have to go. He spent the next hour hiding in the supply closet, questioning every life choice that had led him to this moment.

The team, meanwhile, was blissfully unbothered. The boys had gotten used to Atsumu's changing body with remarkable speed. They treated her exactly the same as before—which is to say, they argued with her, laughed at her, and occasionally threw towels at her head when she got too cocky.

"Nice set, Miya," Suna said one afternoon, not looking up from his phone. "You're getting better at faking left. Also, your bra strap is showing."

"Thanks, I know," Atsumu said, adjusting it without a hint of embarrassment. "Got it in a cute color, too. Want to see?"

"Absolutely not."

"Your loss."

Osamu, watching from the sideline, looked like he was about to ascend to a higher plane of existence just to escape this conversation.

---

Spring break arrived, and with it, Atsumu's bottom surgery.

It had been planned for months. Atsumu had saved up, researched surgeons, talked to therapists, and made all the arrangements herself. She was eighteen, determined, and terrifyingly competent when she wanted to be. Osamu had offered to go with her, but she'd waved him off.

"I'll be fine, Samu. It's just a few days. You'll barely notice I'm gone."

He noticed. He noticed so much that he couldn't eat, couldn't sleep, and ended up sending her twenty-three texts in a single evening, most of which just said "u ok??" over and over again.

Atsumu replied with a single photo of her middle finger and the words "I'm FINE, stop textin', I'm tryna sleep."

When she came back, she was fully female. Not transitioning. Not in process. Done.

The first practice after break was a strange one. Atsumu walked into the gym with her head held high, her body different but her spirit exactly the same. She grinned at her teammates, cracked a joke at Suna's expense, and demanded that Kita-san let her run the new drill she'd thought up over break.

The team accepted her without missing a beat, because of course they did. She was still Atsumu. Still the best setter they'd ever seen. A few more curves and a different set of anatomy didn't change that.

The locker room, however, was another story.

Atsumu strolled into the boys' locker room after practice, still in her sweaty jersey, and started unbuttoning it without a second thought. The boys barely glanced up. Ginjima was toweling off his hair. Suna was scrolling through his phone. Akagi was doing some kind of weird stretching routine in the corner.

Osamu, though, nearly had a heart attack.

"Tsumu!" he yelped, his voice cracking so badly it came out in two different octaves. "What—you can't—this is the boys' locker room!"

Atsumu paused, one hand on her collar, and raised an eyebrow. "Yeah? And?"

"You're a girl!"

"Yep. Good observation, Samu. Real sharp today." She resumed unbuttoning her jersey, revealing the lacy bralette underneath. "What's your point?"

Osamu made a noise like a deflating balloon. "You can't just... change in here! In front of everyone!"

"Why not?" Atsumu asked, genuinely curious. "I've been changin' in here for years. Nothin's changed."

"Everythin's changed! You've got—" He gestured vaguely at her chest, then immediately looked away, his face turning the color of a ripe tomato. "—stuff now!"

The team had stopped pretending not to watch. Suna had even put down his phone, which was a monumental occasion.

"She's got a point, Osamu," Akagi said, grinning. "We don't mind. She's one of the guys. Well. One of the team."

"I'm literally the only girl on the team," Atsumu pointed out.

"And you've always been the only one with that much attitude," Suna added. "So nothing's changed."

Atsumu beamed at him. "I love you, Suna."

"Don't."

Osamu looked around at his teammates, searching for backup, and found none. They were all perfectly comfortable with Atsumu stripping down to her underwear in the middle of the locker room like it was the most normal thing in the world.

It was not normal. It was deeply, profoundly, catastrophically not normal.

"Just... can you change in the girls' locker room?" Osamu pleaded. "Please? For my sanity?"

"The girls' locker room is on the other side of the school," Atsumu said, pulling off her jersey. "I'd have to walk all the way across campus. It's inconvenient."

"You're willin' to inconvenience me for the rest of the school year?"

"Yes."

---

Over the next few weeks, Osamu developed a routine. Every day after practice, he would station himself in front of Atsumu's locker, arms spread wide, determined to block her from changing.

It never worked.

Atsumu was faster, smarter, and completely unafraid to use underhanded tactics. She'd distract him with a sudden question ("Samu, did you remember to get Ma a birthday present?"), then slip past while he was panicking. She'd fake going toward the showers, then double back. One time, she simply climbed over the bench and changed behind him while he was still guarding her locker, completely ignoring his sputtering protests.

"Hey, Osamu," Suna said one afternoon, watching the spectacle with mild amusement. "You know she's just gonna keep doing this, right?"

"I have to try," Osamu said through gritted teeth, still holding his defensive stance.

"You really don't."

But Osamu couldn't stop. The thought of his sister—his sister—changing in front of a bunch of teenage boys made his skin crawl. Never mind that those teenage boys were his teammates, that they'd known Atsumu for years, that they treated her like a sibling. Never mind that Atsumu herself was perfectly comfortable and had explicitly told him to mind his own business.

Osamu Miya had become the world's most overprotective brother, and he couldn't seem to turn it off.

---

The lingerie was the final straw.

It was a Friday afternoon, and practice had run late. Everyone was tired, sweaty, and eager to get home. The locker room was buzzing with the usual post-practice chaos—towels flying, water bottles being chugged, Suna complaining about something on his phone.

Atsumu walked in, pulled off her jersey, and revealed a black lace bralette that had no business being that scandalous. It was delicate, pretty, with a tiny bow in the center and straps that crisscrossed elegantly down her back. She paired it with matching lace underwear that rode high on her hips, and she wore the whole ensemble with the casual confidence of someone who knew exactly how good she looked.

The locker room went quiet.

Not because the boys were staring—okay, some of them were staring, but mostly because they were stunned that Atsumu would wear something so revealing in a room full of people. Even Suna, master of indifference, did a double-take.

"Nice set," he said finally, deadpan.

"Thanks," Atsumu said, preening. "Bought it last weekend. Cost a fortune, but it's worth it."

Osamu, who had been drinking water, choked so hard he sprayed it across the floor.

"TSUMU!"

"What?" She turned to face him, hands on her hips, clearly enjoying his distress. "It's just underwear, Samu. Everyone wears it."

"Not like that! Not in front of—in front of everyone!"

"Oh, please." Atsumu rolled her eyes and turned back to her locker, deliberately slow, making sure he got the full view. "It's not like I'm naked. And even if I was, it's not a big deal. Bodies are bodies."

"Bodies are NOT bodies!"

"Samu, you're bein' dramatic."

"I'm bein' dramatic? You're the one who walked into a boys' locker room wearing nothin' but dental floss!"

"It's lace," she corrected. "There's a difference."

"There IS NO DIFFERENCE!"

The team watched the exchange like it was the best entertainment they'd had all year. Akagi was openly laughing. Ginjima had his face buried in his hands, shoulders shaking. Suna was filming on his phone.

"This is goin' in the group chat," Suna announced.

"If you send that, I'll kill you," Osamu said, his voice flat and dangerous.

"If you kill me, I'll send it anyway from beyond the grave."

---

The breaking point came two weeks later, during a practice match against a neighboring school.

It was a close game. Inarizaki was winning, but just barely, and the tension in the gym was thick enough to cut. Atsumu had just executed a perfect quick attack, and the crowd was still roaring when the whistle blew for a timeout.

The team gathered around Coach Kurosu, sweating and panting. Atsumu was glowing—literally glowing, her face flushed with exertion and victory. She peeled off her practice jersey without thinking, revealing the sports bra underneath, and grabbed a towel to wipe her face.

And that's when Osamu snapped.

He burst through the huddle like a feral animal, nearly knocking over Ginjima in the process. His face was red, his eyes were wild, and he looked like he was about to have a full-scale meltdown right there on the court.

"THAT'S IT!"

The entire gym fell silent. The opposing team stared. The referees exchanged confused looks. Coach Kurosu sighed like he'd been expecting this.

"Atsumu, you CANNOT keep changin' in front of everyone! It's not—it's not proper! You're my sister! My sister! And you're just—standin' there—in your underclothes—like it's nothin'!"

Atsumu blinked at him, towel still pressed to her face. "Samu, we're in the middle of a match."

"I DON'T CARE!"

"Osamu," Kita said calmly, stepping forward. His quiet authority cut through the chaos like a knife. "This is not the time or place."

"Kita-san, I can't—she won't listen—"

"Samu." Atsumu's voice was soft, cutting through his panic. She'd dropped the teasing, the mischief, the smugness. She looked at him with something gentle, something almost vulnerable. "Can we talk after the match? Just you and me?"

Osamu's mouth opened and closed a few times. Then his shoulders sagged, the fight draining out of him. "...Fine."

The match resumed. Inarizaki won, three sets to one. Atsumu played like a demon, setting with precision that bordered on supernatural, as if she had something to prove.

Afterward, while the team celebrated in the gym, Atsumu pulled Osamu aside to a quiet hallway.

"Alright," she said, crossing her arms. "Spill. What's really goin' on?"

Osamu leaned against the wall, staring at his shoes. "I don't know. I can't explain it. I just... I feel like I have to protect you. Like if I don't watch out for you, somethin' bad'll happen."

"Samu, I'm not gonna break. I'm still me. I can still fight, I can still set, I can still kick your ass at video games."

"I know."

"Then why are you actin' like I'm made of glass?"

He was quiet for a long moment. Then, in a voice so small it barely carried: "Because I'm scared."

Atsumu's teasing demeanor softened. "Scared of what?"

"Scared that I'll mess up. That I'll treat you wrong, or say the wrong thing, or make you feel like I don't accept you." He finally looked up, his eyes bright with unshed tears. "I do accept you, Tsumu. You're my twin. You're my other half. But I don't know how to be a brother. I've only ever been your competitor, your rival, your annoyance. I don't know how to be gentle."

Atsumu stepped closer, reaching out to grab his hand. "Then don't be gentle. Be Samu. Be the idiot who steals my food and calls me a dumbass. That's all I ever wanted."

"You're not... mad that I've been hoverin'?"

"I've been annoyed, not mad." She squeezed his hand. "But Samu? I change in the boys' locker room because it's what I'm used to. It's where I've always changed. The guys don't care—they see me as one of them. And frankly, it's safer for me to be around people who already know and accept me than to go to a new locker room where I might not be welcome."

Osamu's face crumpled. He hadn't thought of it that way. He'd been so focused on his own discomfort that he hadn't considered what Atsumu might be feeling.

"I'm sorry," he said. "I'm an idiot."

"Yeah, you are." But she said it with a smile. "But you're my idiot. And I love you."

"Gross. Don't say that."

"Too late. I said it. It's canon now."

Osamu let out a wet laugh, wiping his eyes with the back of his hand. "You're insufferable."

"And you're overprotective. We're even."

They stood there in the hallway, hands clasped, breathing the same air the way they'd done since before they were born. Then Atsumu punched him in the arm—hard, the way she used to—and grinned.

"C'mon. The team's waitin'. And I think Suna's still got that video of you yellin' at me. We've gotta delete it before it ends up online."

"We? You're the one who was walkin' around in nothin' but lace!"

"That's your fault for lookin'."

"It's my fault?! It's my fault for lookin?! You were right there!"

"Should've averted your eyes, Samu. Basic brother protocol."

"I'm gonna kill you."

"You'll have to catch me first!"

And she was off, sprinting down the hallway with a laugh that echoed off the walls. Osamu watched her go, shaking his head, a reluctant smile tugging at his lips.

She was still Atsumu. Still loud, still annoying, still the best setter he'd ever seen. Still the person who knew him better than anyone, who pushed his buttons and stole his food and drove him absolutely crazy.

She was his sister. And he wouldn't have it any other way.

---

The spring tournament came and went. Inarizaki made it to the finals, and though they lost in a heartbreaker of a match, Atsumu was named Best Setter. She accepted the award with her characteristic smugness, then burst into tears when she saw Osamu crying in the stands.

"Stop it," she sobbed, shoving his shoulder. "You're makin' me cry now, you idiot."

"You were already cryin'," he sniffled.

"Was not."

"Were too."

"Are we gonna hug or what?" Ginjima interrupted, arms already open.

The team piled into a group hug, sweaty and gross and full of emotion. Kita stood to the side, allowing himself a small smile. Suna was, predictably, taking photos.

In the middle of the chaos, Atsumu found herself wrapped in Osamu's arms, his chin resting on top of her head.

"You did good, Tsumu," he murmured.

"I know," she said, her voice muffled against his chest.

"Don't let it go to your head."

"Too late. It's already there."

He laughed, the sound rumbling through his chest, and held her tighter.

Brother and sister. Rivals and teammates. Two halves of a whole, finally understanding each other.

It wasn't a perfect ending—their lives were just beginning, after all. But for now, in this moment, surrounded by their teammates and the echo of a hard-fought match, the Miya twins were exactly where they were supposed to be.

Together.