Chapter Text
“Mahiro-chan, look at this!”
“Mahiro-chan, come look!”
“Mahiro-chan, here!”
Mahiro felt so happy, watching Momiji run around all excited. They were at the aquarium, just the two of them, and just about every exhibit was pulling Momiji in with its awesomeness. To Mahiro, it was nothing special; he’d visited the aquarium a few times back in middle school, and Mihari had talked his ear off about every single type of fish and other sea animal they came across, even without prompting. He retained almost none of that info, but it was still a fond memory for him.
“Hey hey, maybe you should slow down a little,” he laughed. She turned to him, a bright, angelic smile on her face, and he felt his heart beat faster for a moment. ‘E-Eh? What was that?’
“Hey, Mahiro-chan, you’re standing too far away,” Momiji said, taking his hand.
Mahiro felt a shiver wash over his body. ‘Direct contact?! Momiji is too bold! … Wait, we’ve held hands before, what am I thinking?’
“Waa! Look, penguins!” Momiji pulled Mahiro to the window of the penguin enclosure, holding his arm. “So cute!”
Mahiro blushed as Momiji held his arm against her chest. ‘No, stop! Calm down, there’s not even anything there! Besides, even if there was, there’s no way you can be having feelings for this girl!’ Mahiro gasped, suddenly losing himself in thought. ‘Wait, who said anything about feelings? Where did that come from? C’mon man, get it together! Momiji’s just a friend, a friend who could be your little sister, there’s absolutely no way, zero chance, that you have feelings for-’
“Mahiro-chan?” Mahiro turned, and was greeted to a brilliant, shining smile staring directly into his eyes. “Thank you for coming with me today. I’m having the best time ever.”
‘This angel!’ Mahiro stuttered, completely paralysed. He reached for the two brain cells that were still operational and rubbed them together enough to form a coherent, “N-No problem. Eh-heh-heh…”
Momiji tilted her head, but didn’t question the odd response. She sniffed the air, and whipped her head around, spying a crepe stand. She stared at it, her face tinged red as she felt her stomach rumble.
“Would you like a crepe, Momiji?”
Momiji whirled on Mahiro. “N-No, it’s okay, you don’t have to!”
“C’mon, let me treat you. You must be hungry from all that running around.”
Momiji grumbled. “T-Then, only if you let me feed you, Mahiro-chan.”
“Um, okay?” ‘What kinda deal is that? Momiji feeding me…’ Mahiro’s heart fluttered. ‘I feel like I’m getting the better end of it.’
Mahiro bought the crepes and they sat down at a nearby bench. Momiji offered hers to him. “Open wide, Mahiro-chan.”
Mahiro blushed, looking around to make sure nobody was watching, and then he opened his mouth, allowing Momiji to feed him. ‘What the hell? This crepe is so good! No, it’s not the crepe… it’s being fed by Momiji! Why does this feel so awesome?!’
“M-Mahiro-chan,” Momiji said, brushing her hair aside and opening her mouth.
Mahiro almost crushed the crepe in his hand, but thankfully, he kept enough control to guide it to her mouth. Even with his hands shaking, he managed to hold it there while she bit into it, taking small, gentle nibbles.
‘Ah, fuck. I’m in love.’ Mahiro felt a wave of dread wash over him. ‘I shouldn’t be, but there’s no denying it anymore.’
Momiji pulled back, smiling sweetly. A little cream was stuck to her cheek, and when Mahiro wiped it off with his thumb, her face became flushed and she muttered, “T-Thanks.”
Mahiro licked the cream of his thumb, looking away. “No problem…” ‘I’m in love with Momiji.’
“Mihari, change me back right now!” Mahiro shouted as he barged into her room. Mihari quickly minimised something on her computer and turned to him with a start, and he stared blankly at her. “Ah.”
“Onii-chan, knock before you enter!” Mihari scolded.
“Now you know how it feels,” he said, feeling victorious over something. “It’s okay if you’re looking at porn, Mihari. There’s nothing wrong with-”
“I’m not!” Mihari protested. “I’m working on the medicine research right now, but it’s classified data so I hid it on instinct!”
“Even if I saw it, I doubt I’d understand any of it,” Mahiro said. “Anyway, that’s not important right now! You have to change me back!”
Mihari tilted her head. “Why? Did something happen?”
Mahiro blushed, looking away. “N-Nothing in particular…”
Mihari grinned. “Reeeeeeally? You just suddenly wanna go back to your true self out of nowhere? Seems kinda fishy, Onii-chan.”
Mahrio glared at his sister. “It’s all your fault! Turning me into this, making me go to school! It’s your fault I’m feeling this way for-” He stopped himself, clamping his hands over his mouth.
Mihari stared at him, shocked. She rose to her feet and approached him, kneeling to meet his eyes. “Onii-chan? It’s okay, I won’t think any less of you.”
Mahrio may not be as smart as his sister, but even he could tell that she knew what he was going to say, and just wanted him to say it. “I… I think I might like Momiji…”
Mihari sighed. “Onii-chan-”
“It’s nothing perverted! She’s just, she’s so cute and full of energy, and we always have so much fun together and I kinda feel like I don’t want our days hanging out together to end!” Tears were welling in Mahiro’s eyes. “And my chest tightens and my stomach churns when I’m with her and, and…”
Mihari patted her brother, looking into his eyes with a reassuring smile. “There, there. First loves are hard, aren’t they?”
“It’s not my first love!”
“First 3D loves are hard, aren’t they?” Mahiro grumbled, but didn’t deny it. “I know, Onii-chan. I know it’s nothing sinister. You’re not that kind of guy.”
Mahiro hung his head. “Even so, this has gone too far. I need to go back to my old life now. Please.”
Mihari took out a bottle and handed it to him. “This is the antidote. It’ll change you back right away, if that’s what you really want.”
“… You had this the whole time?!”
“W-We only just perfected it! You didn’t seem like you were in any rush to return so-”
Mahiro sighed, pocketing the bottle. “Whatever.”
“You’re not going to take it?”
“… There’s something I need to do first. I need to come clean to her.”
“Her? You mean Momiji-chan?” Mihari looked uneasy. “Are you sure that’s a good idea?”
“She deserves it. She’s so clearly in love with me, but I’ve been deceiving her this whole time. It’s not fair.”
“Wow, so Onii-chan isn’t too dense to see when someone likes him?”
Mahiro puffed out his chest in pride. “I’ve played enough eroge to be able to pick up on people’s feelings!”
“I don’t think that’s how that works.”
“How do you know? Have you played any?”
Mihari huffed, crossing her arms. “No, and I don’t intend to!”
Mahiro pointed his finger. “Then you can’t claim that they’re no good as a learning material for human interactions!”
Mihari recoiled. “Shock!” Then, she settled down. “No, I’m still certain that there’s only so much you can learn from them. Momiji-chan just doesn’t exactly hide her feelings for you.”
“Either way, I’m gonna tell her! It’s the right thing to do… right?”
“Well, morally-speaking.”
“And you’ll be there, too!”
“Why me?!”
“Because I need support! Besides, what if she freaks out?! What if she tries to call the cops?!”
Mihari grumbled. “F-Fine, I’ll be there…” She gave her brother a playful grin. “If nothing else, I suppose I should make sure you don’t take things too far.”
“So you do think that little of me! You’re mean!”
The call was made. Momiji was on her way to the Oyama household to visit Mahiro. She didn’t know why she was called so suddenly, but it was an excuse to spend time alone with Mahrio, so who cares?
The two siblings waited in Mahiro’s room, the sister sitting backwards in a chair, and the brother on his knees formally on a cushion, wearing an oversized bathrobe. The tension started to weigh heavy between then, and Mahiro grumbled. “M-Maybe I should take a drink to relax…”
“No,” Mihari said. “You had your one drink this morning.” Mahiro was allowed one alcoholic beverage a day. As an adult, there was no real reason to deny him his right to drink, but his small body was delicate, and there were concerns about the effects of alcohol mingling with the drug, so this was the compromise they had agreed on. She was just glad her brother wasn’t a smoker, because they already knew that cigarettes did not impact the drug at all.
“But this is a special circumstance! Besides… it won’t be long now.”
Mihari didn’t respond to that. The two continued waiting in silence, when the doorbell rang. Mihari stood and left the room, and Mahiro’s nerves went haywire. He started to second-guess himself, he fidgeted and clenched his fists. Mihari returned moments later with Momiji, who looked confused.
“H-Hey,” he said.
“Hey, Mahiro-chan,” Momiji said, watching as Mihari sat down. “What’s-”
“Have a seat,” Mahiro said. “There’s something important I have to say.”
Momiji sat on her knees, on a cushion placed in front of Mahiro. She felt like she was there for an interview or something. “Mahiro-chan?”
“Momiji… Sorry, I uh, I’m just gonna come out and say it.” Mahiro took in a deep breath. “I have… feelings for you.”
Momiji simply stared at Mahiro, a blank smile on her face, and she blinked. “E-Eh? Mahiro-chan?” Her face reddened. “W-W-W-Wait! W-What are you saying?! And with your sister watching-”
“I like you, Momiji. I like you a lot, and I wanna go out with you-”
“M-M-M-Mahiro-chaaaaan?!” Momiji’s heart was pounding, and her face was like a setting sun. “S-S-So sudden! You’re assaulting me here!”
“I’m sorry,” Mahiro said, bowing his head. “I had to let you know how I felt. We can’t be together, Momiji.”
And just like that, time seemed to stop. Momiji lowered her hands from her face, her breathing became shallow, her chest constricted. Tears glistened in her eyes. “Why?”
“Because… I’ve been lying to you this whole time.” Mahiro raised his head, revealing that he, too, was crying. “I’m not Mahiro Oyama, Mihari’s younger sister. I’m… Mihari’s older brother.”
“Eh?”
Mahiro took out the bottle, then turned to Mihari. She simply nodded, and he downed the contents. His eyes shot open and he clutched his throat, struggling to breath. He cried out in pain, and steam emitted from his body.
“M-Mahiro-chan?! What did you drink?! Mihari-san, you have to help!”
“GAHHHHHH!” Before Momiji’s eyes, Mahiro’s body began to change. She grew taller, fitting neatly into the bathrobe. Her hair receded, her eyes became sharper, her shoulders became broader. She could only watch in horror as her best friend and crush turned into a man, clutching his throat and panting. As he lifted his head, she saw a striking resemblance to Mahiro. He was almost as cute as her, but also a little handsome. “W-What the hell, Mihari?! That hurt so much worse than the drug!”
“W-Well this is the first field use of it! Are you okay?”
“I… I think so…” Mahiro raised his head, looking into Momiji’s eyes. He reached out a hand, but stopped when she shuffled back. “Sorry… Y-You can run away, if you want.”
Momiji wasn’t sure what she wanted. She shot up and quickly left the room, closing the door. Mahiro sighed, hanging his head, but before long, the door reopened, and a new girl stepped in, wearing her hair down.
“Who are you?” he asked, narrowing his eyes. “Wait, Momiji?!”
“Mahiro-chan, it’s really you!” Momiji said, taking her seat again. “… I don’t understand. What happened? Why are you suddenly a man?”
Mahiro explained to Momiji everything about the drug and his circumstances. As he spoke, she seemed to calm down, at least a little. She listened intently, her hand over her chest the whole time, feeling her heart racing.
“And so that’s basically it,” Mahiro concluded. “I’m sorry for deceiving you, and for everything. I’ll never appear before you again. I never meant to cause you any harm, Momiji.”
“Mahiro-chan…” Momiji shook her head. “You never caused me any harm. Is it true though, that you love me?”
Mahiro frowned. “Y-Yeah. I know it must freak you out. I don’t understand it myself, either, but I just can’t help how I feel about you…”
Momiji held her hands together, staring into Mahiro’s eyes. “And it would be a problem… why? I love you too, Mahiro-chan.”
“Momiji, you can’t-”
“But I do. Even seeing you like this, even knowing your true identity, I just can’t stop how I’m feeling. I don’t want to lose you, Mahiro-chan, so please don’t go anywhere. Please don’t say this is goodbye.”
Both Mahiro and Mihari were stunned, to say the least. Mahiro was silent for a long while, until Momiji shuffled a little closer, and then he said, “Wait, you’re not disgusted by this?”
Momiji shook her head. “You’re the same Mahiro-chan, I can tell that. You’re sweet and kind, and so cute.” She saw him blushing, and it made her smile. “And to know now you feel the same way for me that I feel about you, there’s no way I could be okay with never seeing you again.”
“But I’ve been lying to you, and the others. I’m an adult that’s been hanging out with you like I’m a child! Doesn’t that make you angry?!”
Momiji shook her head. “I understand your… circumstances. Thinking back on all the time we’ve spent, it’s been so much fun. You being an adult doesn’t change that, at least for me.”
Mahiro could only stare in awe, his hand over his chest, feeling his beating heart. ‘No wonder I fell for her. Momiji is… amazing.’
Momiji then shifted her gaze to Mihari, who had been watching the exchange with rapt interest. “The one I’m mad at right now is Mihari…”
Mihari flinched, pointing to herself. “M-Me?”
Momiji nodded, looking sternly at the younger sister. “You gave him the drug without him knowing, and pushed him into this new lifestyle. How could you do that do someone you love?”
Mihari felt her heart sinking, and she quickly averted her eyes. “I-I just wanted to help Onii-chan, because-”
“Momiji,” Mahrio said, “I get where you’re coming from, but really, it’s fine! I’m much happier now than I was before, so-”
Momiji spun on Mahiro, shaking her head. “No, it’s not okay! Even if you’re happier now, the ends don’t justify the means! She should have asked you!” She noticed Mahiro looking conflicted, and she took a breath. “Mahiro-chan, you… really love your sister, don’t you? You’re such a kind person, after all.”
Mahiro blushed, fiddling with his hair, forgetting for a moment that he was in his true form. “That’s…”
“You need to be honest though. You can’t spoil her because she’s cute!” Momiji crossed her arms, pouting. “If Onee-san had done that with me, I would be a bad girl by now!”
‘Eh? It was my job to set Mihari on the right path? How could I do that when I myself strayed so far?’
“If I’d asked him,” Mihari began, “He would have said no for sure. That’s why I felt I had to…” Mihari trailed off, her own words sounding bad to her as she thought them through.
“… T-That would have been my choice, though,” Mahiro said, turning to Mihari. “Mihari, I… When this all started, I kinda felt for just a bit that I… hated you…” Mahiro’s voice dropped as he said it, but both Momiji and Mihari heard it clearly. “Like, how could you do this to me? Do you see me as nothing but a toy?” Both siblings were tearing up, and Momiji wasn’t far behind, but she remained strong for the both of them as she watched. “Did I really hurt you that much?”
“No!” Mihari jumped off of her chair, pulling Mahiro into a hug. “No, Onii-chan, it isn’t like that! I’m sorry, I’m sorry!”
Mahiro hugged Mihari as she cried into his shoulder, and he patted her head. “I don’t hate you anymore, though. You helped me, so I thought I could just let it go.”
“I… I was so scared for you, Onii-chan. I thought you’d waste away all alone, dying with no one but me to mourn you. I couldn’t reach you as you were, so I thought I had to take drastic measures. I was ready for you to yell at me, or even kick me out of the house, but when I saw how much fun you were having, I felt like I wanted to make up for lost time…”
“Lost time?” Mahiro closed his eyes. “Sorry, I neglected you for a while, didn’t I? I really am trash…”
Momiji watched the siblings crying it out and apologising. Her heart fluttered at the sight. “You’ve never scolded her before, have you?” she asked.
“No,” Mahiro admitted.
“Onee-san scolds me whenever I misbehave, and it hurts… but you know, when we hug it out after, I feel so happy and warm. It’s one of the best feelings in the world.”
Mahiro held Mihari tighter, and she choked out a few more sobs. “Mihari, it’s okay. I forgive you,” Mahiro said. “Just, from now on, don’t drug me without my consent, okay?”
Mihari laughed. She couldn’t help it. “Yeah, I promise. I love you, Onii-chan.”
“I love you too.” Mahiro turned to Momiji, smiling. “You’re right, this feels nice.”
Momiji nodded, and then she waited patiently until the two got it out of their systems and parted. “So,” Momiji began, playing with the cushion beneath her, “Where does this leave… us?”
Mahiro murmured. “You can forget all about me. Tell the others I had to move away or something.”
“… I love you too, Mahiro-chan,” Momiji said. “Not matter what form you’re in, I just want to spend more time with you. So please, don’t go anywhere. Even if you change back, we can… we can make it work, can’t we?”
"But the age gap-"
Momiji pouted. "It's only seven years! Even my parents have a bigger gap than that."
Mahiro had to admire her innocence, but he knew better. At least, he thought that he did, but for some reason his immediate response wasn’t a ‘no’. “I… need to think.”
“Okay…” Momiji leaned forward, kissing Mahiro’s cheek. Then, she picked herself up and left the room, leaving Mahiro and Mihari to themselves. They didn’t even get up to see her out, instead simply waiting for the sound of the front door closing.
“Onii-chan,” Mihari said, “You really love her, don’t you? You shouldn’t throw that out just because-”
“Mihari, you know that it’s wrong.”
Mihari shook her head. “I’m a mad scientist, I don’t worry about things like right and wrong. What I know is that love is always an unpredictable, chaotic factor in all fields of study. My senpai and I have discussed this before, the possibility of you falling in love.”
“You have?!”
“We know you’re not the kind of person to take advantage of a girl, and that you’re not some pervert who would prey on middle schoolers. I mean, you are a pervert, but you’re also kind, and I know you’d never hurt someone.”
“Even so-”
“Nobody else would know. You could go on living as the middle schooler Mahiro-chan, and you could date Momiji. As long as Momiji is okay with it, we won’t object.”
Mahiro was silent for a while, his eyes closed as he weighed his options. “… Hey, can I ask something?”
“Sure?”
“I probably should have asked this sooner but, why is it that the medicine turns me into a girl? Why didn’t you just turn me into a young boy?”
Mihari looked away awkwardly. “A-About that, we are developing another medicine like that, but it works way differently cause of… well, it’s complicated. Unfortunately we’re short-handed so, we could only really focus on one at a time.”
“So why the girl one?” Mihari looked away. “Mihari, why did you focus on the girl medicine specifically?”
“… Does it matter?”
“It matters to me! You just wanted to dress me up in cute clothes and treat me like a little sister, didn’t you?!”
Mihari recoiled. “Exposed?!”
“Mihariiiiiiii!”
Mihari clapped her hands together, bowing her head. “Forgive me, Onii-chan! I swear I’ll work extra hard on the male variant starting tomorrow!”
Mahiro sighed, leaning back and letting out a small laugh. “Well, I guess it’s fine. For now though, becoming a young girl is my only option, isn’t it?” Mihari nodded. “… I still haven’t decided, but, can you give me the medicine?”
Mihari handed him a bottle of the medicine, and then Mahiro asked to be left alone to think. She left the room, turning to back to see him staring at the bottle, deep in though. After returning to her own room, Mihari sat down on her bed and leaned against the wall, a faint smile across her face. “Good luck, Onii-chan…” A tear rolled down her face. “Dummy. If I’m so unconcerned about morality, I should’ve made my move sooner…”
Mihari took out her phone, dialling a number. “Hey Mihari! What’s up? It’s kinda late.”
“Hey Kaede,” Mihari said, her voice low. “I just got rejected…”
There was a long silence, before Kaede’s voice boomed through the speaker. “Are you okay?! What happened?!”
“I’m fine. He liked somebody else, that’s all.”
“Who- No, never mind. I’m on my way right now, just please don’t die!”
Mihari laughed. “I’m not gonna die, stupid.” She fiddled with the strap attached to her phone. “Tonight’s no good, can you give me a day to sort through my feelings?”
“… Of course. Y’know, I’ve never heard you this vulnerable before.” A silence passed. “Thanks for reaching out to me.”
Mihari fell onto the bed on her side. “Well, you’re the only friend I could think to call about this.”
“Whatever you need. I’m here for you, girl.” There was another brief pause. “I love you, Mihari. Ah! N-Not in that way, I’m not trying to swoop in or anything, I mean as a friend, I-”
Mihari burst out into laughter. “I know what you mean. Thank you.” She hung up the phone and buried her face into her pillow.
The following day, Momiji walked to school with a forlorn look on her face. She was quiet even as Kaede spoke to her and asked her questions, not really paying any attention to them. Kaede could sense her sister’s troubles, but since Momiji wasn’t responding to her questions, she reluctantly decided to leave her to her thoughts.
After the two parted ways, Momiji approached the gates to her school. It felt wrong not walking together with Mahiro, but by now, she- he, was probably trying to put his life back together again as an adult. He lived in a different world now, and there was no place for her there.
“Good morning, Momiji!” Mahiro greeted, standing in her path.
Momiji blinked, then blinked again. Mahiro was standing there, no longer the man she saw yesterday, but the girl that she first fell in love with several months ago. “M-Mahiro… chan?”
Mahiro stepped closer, his face tinged red. “Hey,” he said, stopping just in front of her. “I uh, I’m gonna stay… like this. With you.” Mahiro pressed his fingers together, suddenly bashful. “I-If that’s oka-” He didn’t get to finish. Momiji leapt forward and hugged him.
“I love you!” she declared, so loudly that all chatter around them stopped.
Mahiro blushed intensely, but when he felt Momiji shivering, he just couldn’t bring himself to scold her or push her away. Instead, he wrapped his arms around her, tears in his eyes. “I love you too.” His voice was far quieter, but she heard it. “If you’re okay with a hopeless man like me-”
“I want to be your girlfriend, Mahiro-chan,” Momiji said. “Boy or girl is fine with me, Mahiro is Mahiro.”
Mahiro nodded. “I’ll be in your care, then.”
The two smiled, until they were reminded of their present situation as cheers and applause rang out around them. Some students whistled, others told them to get a room. One teacher ran over, yelling, “What are you doing?! You’re at school!”
The two quickly parted, their faces so red that one might think they were sunburnt. They looked at each other… and then they laughed. They laughed so hard that it hurt, and the gathered crowd decided to just leave them to it, moving right along.
When they were finished, Momiji held out her hand. “Let’s go, Mahiro-chan.”
Mahiro nodded, firmly holding Momiji’s hand.