Under the Same Skin

The morning sun snuck through the curtains of the Miya twins’ room, and Atsumu woke up groaning. He stretched—felt that familiar pull in his limbs—but something was off. There was this weird weight on his chest, like pressure that hadn’t been there last night. He frowned, rubbed his eyes, and pushed himself up.

Then he looked down. And his breath caught.

His T-shirt—that loose, faded one he always wore to bed—was tight across his torso. Two soft mounds pushed against the fabric. His hands flew to his chest. Eyes wide, he stumbled out of bed and into the bathroom, locking the door. He stared at his reflection, at the gentle curves that had appeared overnight. The world tilted.

“No way,” he whispered. “No way, no way, no way.”

Panic crawled under his skin, hot and itchy. He grabbed the biggest T-shirt he had—an old hoodie from a training camp—and pulled it on, hoping the baggy fabric would hide the change. But his fingers were shaking.

The bathroom door rattled. “Oi, Atsumu, you gonna be in there all day?” Osamu’s voice, flat and bored, came through the wood.

“Shut up!” Atsumu snapped, his voice cracking. He splashed cold water on his face, took a deep breath, and opened the door. Osamu was leaning against the hallway wall, arms crossed, already dressed in his school uniform.

“You look like a ghost,” Osamu said, his eyes narrowing. Then they dropped to Atsumu’s chest, where the hoodie still pressed against the new curves. “Huh. What’s that?”

“Nothin’,” Atsumu said, stepping past him. But Osamu grabbed his arm.

“Let go,” Atsumu growled, trying to twist free. But Osamu’s grip was firm, and with his other hand, he tugged at the hoodie’s collar, peering down.

“What the—? Did your chest get bigger?” Osamu’s tone was pure curiosity, but Atsumu’s face burned. He yanked his arm away.

“Don’t touch me, you idiot!”

“I’m just askin’,” Osamu said, a smirk forming. “Look at you. Little brother’s turnin’ into a girl.”

Atsumu’s vision went red. He shoved Osamu, hard, and Osamu stumbled back, laughing. “Shut up! Shut your mouth!”

Their mother appeared at the top of the stairs, a wooden spoon in her hand. “What’s all the shouting? Osamu, what did you do?”

Osamu pointed at Atsumu, still grinning. “He’s got boobs now.”

The spoon came down on his head with a sharp thwack. “Ow! Mom!”

“Don’t tease your brother,” she said, her voice stern but her eyes soft when they landed on Atsumu, who was trembling, arms wrapped around himself. “Atsumu, come with me.”

She led him to her bedroom, sat him on the edge of the bed, and knelt in front of him. “Did you notice this morning?”

He nodded, staring at his knees.

“It’s normal,” she said gently. “This happens to a lot of boys, when their hormones change. Sometimes the body goes through… something a little different. Nothing to be ashamed of.”

Atsumu’s throat tightened. “But I’m not a girl. I’m a boy. I play volleyball. I’m gonna be the best setter in the world. This can’t—I can’t have—”

“You can have whatever you want,” his mother said firmly. “And your body is just going through its own journey. We’ll talk to the doctor, see what’s happening, okay? For now, you can wear a sports bra if it helps. I have some that might fit.”

Atsumu felt a tear slip down his cheek and angrily wiped it away. “I hate this.”

“I know, baby. But you’re not alone.” She pulled him into a hug, and he let himself melt into it, just for a moment. He didn’t see Osamu standing in the doorway, his smile gone, replaced by a quiet, guilty frown.

Later that day, Osamu appeared next to him on the couch, holding out a chocolate bar. “Sorry,” he muttered.

Atsumu took it without looking at him. “Whatever.”

But he unwrapped it and bit into the sweet chocolate, and when Osamu didn’t say another word, just sat beside him in silence, Atsumu allowed himself to relax. Maybe it wasn’t the end of the world.

---

Six months later, the world ended again.

Atsumu woke up with a cramp low in his belly that felt like someone was twisting his insides with a pair of pliers. He groaned, rolled over, and felt a warm, wet stickiness between his legs. His heart froze. He threw back the covers and saw the dark red stain blooming on his gray sweatpants.

“Oh no,” he breathed. “Oh no, no, no.”

The pain doubled him over. He scrambled to the bathroom, his hands trembling as he pulled down his pants. The proof was there, stark and undeniable. He had known this was coming—the doctor had explained it, weeks ago. His body was developing differently, and periods were a possibility. But knowing and experiencing were two different worlds.

“Mom!” he shouted, his voice breaking. “Mom!”

She was in the kitchen, but she heard the panic in his voice and came running. One look at the blood on his pants and she was all business—calm, efficient, loving. She grabbed a clean towel, helped him clean up, and handed him a pad with a quick explanation of how to use it.

“It’s your first one,” she said, brushing his hair back. “They can be rough. I’ll get you some painkillers. You can stay home today.”

Atsumu nodded miserably. The cramps were like waves, crashing and ebbing, leaving him gasping. He curled up on the couch with a heating pad, tears leaking out of his eyes. Everything hurt. Everything.

Osamu came down for breakfast, saw him, and stopped. “You look like death.”

“Osamu,” their mother warned.

“What? I’m not teasin’. I’m observin’.” He walked over and peered at Atsumu’s pale face. “You okay?”

“Leave me alone,” Atsumu whimpered.

Osamu looked at their mother, who simply shook her head. He grabbed a glass of water and set it on the table next to Atsumu, then left for school without another word.

That afternoon, he came back with a bag of chocolate bars and a pack of strawberry milk. He dropped them on the couch beside Atsumu. “Heard chocolate helps.”

Atsumu’s eyes widened. He didn’t say thank you, but he grabbed a chocolate bar and devoured it. The cramps were still there, but the sweetness was a small comfort.

For the next few days, Osamu brought him chocolate every single day. He didn’t say much, just left it on the table or dropped it on his pillow. Atsumu found himself looking forward to it, a tiny spark of warmth in the storm of hormones and pain.

And when the period ended, Atsumu felt like he’d survived a battle. He was exhausted, but also relieved. His mother hugged him. Osamu sat next to him on the couch, and neither of them said a word. But when Atsumu’s hand brushed against his brother’s, Osamu didn’t pull away.

---

Months passed. The periods became a routine—predictable, manageable, though always painful. Atsumu learned to anticipate them, stock up on painkillers and pads, and warn Osamu when he was about to become a raging monster. And Osamu learned to give him space and keep chocolate on hand.

It worked. They had a system.

Until it didn’t.

It was a lazy Sunday afternoon. The twins were sprawled on the living room couch, a rare day off from both school and volleyball training. Suna Rintarou, Osamu’s teammate and friend, was perched on the armchair, scrolling through his phone with his usual impassive expression.

Atsumu had the remote. Osamu wanted it. Atsumu refused.

“Give it,” Osamu said, reaching over.

“No. I was here first.”

“You fell asleep for an hour. You don’t get to keep the remote while you’re unconscious.”

“I’m awake now. And I’m watchin’ this.”

The screen showed some drama Atsumu had been following. Osamu rolled his eyes. “That’s garbage. Gimme the remote.”

“Make me.”

It was a classic Miya twin argument. Suna didn’t even look up; he was used to it. The only sound was the click of his phone as he scrolled.

Osamu lunged. Atsumu dodged, holding the remote above his head. They wrestled on the couch, limbs tangling, neither giving an inch. Then, in a moment of pure desperation, Atsumu scrambled onto Osamu’s lap, using his weight to pin him down while he reached for the remote.

“Oof—get off, you idiot,” Osamu grunted.

“Not until you surrender!”

“Never.”

They were both laughing now, the fight turning into a playful scuffle. Atsumu’s legs were straddling Osamu’s hips, his hand inches from the remote on the floor. He leaned forward—

And felt it.

A warm, wet sensation seeping through his shorts and onto Osamu’s joggers.

Atsumu froze. Osamu froze.

“Uh,” Osamu said, his voice flat. “Is that what I think it is?”

Suna finally looked up. “What’s happening?”

Atsumu scrambled off Osamu’s lap, his face white. The blood was already soaking through his gray shorts, leaving a dark patch on the fabric. And on Osamu’s light-colored joggers, a blooming red stain was spreading like a wound.

“I’m sorry,” Atsumu said, his voice a whisper. “I’m sorry, I’m sorry, I’m so sorry.”

He wanted to run. He wanted to disappear. He felt tears prick at his eyes, hot and humiliating. He had ruined his brother’s pants. He had bled all over him. He was disgusting.

But Osamu didn’t move. He didn’t yell. He just looked down at the stain, then back at Atsumu’s panicked face, and said, “It’s fine.”

“It’s not fine! I got blood on you!”

“We come from the same blood,” Osamu said, and it was so unexpected, so strangely poetic for him, that Atsumu’s brain short-circuited. “It’s just blood. It washes.”

Suna raised an eyebrow but said nothing.

Atsumu’s lower lip trembled. He was about to cry, but then another wave of cramps hit him, doubling him over. He clutched his stomach, groaning.

“Okay, you need to change,” Osamu said, standing up. His joggers were ruined, but he didn’t seem to care. “Go to the bathroom. I’ll get you a pad.”

Atsumu stumbled to the bathroom, his face burning. He cleaned up as best he could, but when he came out, wearing a towel around his waist, Osamu was waiting with a fresh pad and a pair of clean shorts.

“Here,” Osamu said, handing them over. “I’ll put the laundry in the wash.”

“I can do it,” Atsumu mumbled.

“You’re crampin’. I got it.”

Atsumu changed and came back to the living room. Suna was still there, but he had turned off the drama and put on a nature documentary instead. “More appropriate,” he said dryly.

Atsumu sat down gingerly on the couch, hugging a throw pillow. Osamu came back from the laundry room and sat beside him. For a moment, there was silence.

“So,” Suna said, “is that normal for you?”

Atsumu looked at him blankly. “What?”

“The blood. That was a lot.”

Osamu frowned. “What do you mean?”

Suna shrugged. “I’m just sayin’. I’ve been around girls who have periods. That seemed on the heavier side. Plus, I saw the pad you were using earlier. It was completely soaked, and you only put it on like—what, an hour ago?”

Atsumu’s stomach dropped. He had been changing pads every thirty minutes that day. And the overnight pad he’d worn last night had been a disaster—he’d bled through his underwear, his shorts, and the sheets. He’d woken up in a pool of blood. He’d assumed it was normal, because his periods were always heavy.

But Suna was looking at him with that calm, analytical gaze, and Osamu was looking at him with growing concern.

“Atsumu,” Osamu said, his voice low. “How often do you change your pad?”

“Every… I don’t know. Thirty minutes? Sometimes less.”

“And how long does your period last?”

“A week? Maybe more.”

Osamu’s face paled. “That’s not normal.”

“It’s fine,” Atsumu said quickly. “I’m fine. It’s just heavy.”

“It’s not fine,” Suna said, and his tone was so flat and factual that it cut through Atsumu’s denial. “If you’re bleeding that much, you could be losing too much blood. You could get anemic. That’s not good for an athlete. Or for anyone.”

Atsumu’s hands started to shake. He didn’t want to think about it. He didn’t want to admit there was something wrong. He had already had to deal with the weirdness of his body, the questions, the teasing. He didn’t want more.

But Osamu was staring at him with an intensity that made his heart clench.

“Atsumu,” Osamu said, and his voice was gentle now, nothing like the teasing brother from months ago. “Are you scared?”

Atsumu’s eyes filled with tears. He nodded, a tiny, broken motion.

Osamu reached out and took his hand. “Then we’re gonna fix it.”

They called their mother. She came home from the grocery store, took one look at the blood on Osamu’s joggers (still not in the wash), and immediately made an appointment at a clinic. By the next morning, she had Atsumu in the car, heading to a gynecologist.

The clinic was clean and quiet. Atsumu sat in the waiting room, his mother beside him, his hands clasped so tight his knuckles were white. Their mother rubbed his back in slow circles.

“It’s okay to be nervous,” she said. “But you’re doing the right thing.”

The doctor was a kind-faced woman who explained everything clearly. She did an ultrasound, asked about his cycle, and finally gave a diagnosis: menorrhagia—heavy menstrual bleeding.

“It’s not uncommon, especially for someone with your hormonal profile,” the doctor said. “It can be managed. We have several options. Birth control pills can help regulate and lighten your flow. There are also medications like tranexamic acid that reduce bleeding. Or we can look at a hormonal IUD, though that might be more than you need right now.”

Atsumu listened, his heart hammering. Birth control. IUD. The words felt foreign, scary. But the doctor’s voice was calm, and his mother’s hand was warm.

“What do you recommend?” his mother asked.

“Let’s start with a low-dose birth control pill,” the doctor said. “It’s the least invasive, and we can monitor how you respond. If that doesn’t work, we’ll try the next option.”

Atsumu nodded. “Okay.”

He left the clinic with a prescription and a follow-up appointment in three months. His mother bought him a heating pad and a box of chocolates. And when they got home, Osamu was waiting on the couch, next to Suna.

“Well?” Osamu asked.

“I have a prescription,” Atsumu said, holding up the bag. “I’m gonna be okay.”

Osamu nodded, a look of relief passing over his face. Then he stood up, grabbed the remote, and said, “Good. Now we’re watchin’ my show.”

“Hey!”

But Atsumu laughed, and it felt good. He sat down on the couch, and Osamu plopped back down beside him, close enough that their shoulders touched.

Suna handed Atsumu a chocolate bar. “Here. For the pain.”

Atsumu took it, smiling. “You’re not as cold as you pretend, are you?”

Suna shrugged. “I’m just supporting my friend’s brother.”

Osamu snorted. “You’re stuck with us, Suna.”

“Seems that way.”

They watched TV for a while, a mindless reality show that required no thinking. The heating pad was warm against Atsumu’s belly. The chocolate was sweet on his tongue. And the cramps were still there, but they were manageable.

At some point, Atsumu’s eyes started to droop. He leaned against Osamu’s shoulder, feeling the steady rise and fall of his brother’s breathing.

“Tsumu,” Osamu said quietly.

“Mm?”

“You scared me this time. When I saw all that blood.”

Atsumu’s heart squeezed. “Sorry.”

“Don’t be sorry. Just… tell me next time. If you’re worried. If it gets worse. I’ve got your back.”

Atsumu opened his eyes and looked at his twin. Osamu’s face was serious, his jaw set. He meant every word.

“Okay,” Atsumu said. “I will.”

Osamu nodded, then reached over and adjusted the heating pad. “And I’m gonna make sure you always have snacks, so don’t think you’re gettin’ out of that.”

“Wouldn’t dream of it.”

They sat in comfortable silence, the TV droning on. Suna had fallen asleep on the armchair, his phone slipping from his hand. The afternoon light filtered through the curtains, soft and golden.

Atsumu felt the tension drain from his body. He had been so scared, for so long. Scared of his own body, of the blood, of the pain. But now, sitting here with his brother and his friend, he knew he didn’t have to face it alone.

“Osamu?” he said, his voice barely a whisper.

“Yeah?”

“Thanks. For the chocolate. And for not makin’ fun of me.”

Osamu was quiet for a moment. Then he said, “You’re my twin. We come from the same blood. That means I’m in it with you. All of it.”

Atsumu smiled, a real smile, and let his eyes close.

When he woke up, the TV was off, and a blanket had been draped over him. A new heating pad, still warm, was pressed against his belly. And on the coffee table, there was a note in Osamu’s messy handwriting:

More chocolate in the kitchen. Don’t eat it all before I get back.

Atsumu laughed, and the sound echoed in the quiet room, warm and light.

He was okay. They were okay.

And that was all that mattered.