Mahiro's Confusing New Body (anime)

Mahiro's Confusing New Body (まひろとイケないカラダ, Mahiro To Ikenai Karada) is the first episode of the Onimai: I'm Now Your Sister! anime series. It originally aired on AT-X, Tokyo MX, and BS11 on January 5, 2023.

Summary
We follow Mahiro Oyama, an unemployed good-for-nothing shut-in, who not only hasn't left the house in two years, but is also exceedingly addicted to gross video games. One afternoon, he wakes up and notices that his body feels a little off. Finding that strange, he goes to reach for his tablet, but what does he see in his reflection, but an adorable young lady. I wonder what lies in store for the "former" big brother, Mahiro as he's thrust headfirst into his new life as a girl.

Plot
As Mahiro Oyama, an otaku slacker and gamer who hasn't left his house in two years, lies under the covers of his bed, his alarm goes off, revealing that it is 11:38 AM. After he reaches out and hits the alarm, he struggles to get out of bed. It is revealed that his darkened room is a pigsty, with manga volumes, trash bags, food and drink containers, and game cases scattered everywhere.

Mahiro yawns as he gets out of bed, and notes to himself that it is midday already. He becomes confused by his voice being so high, and wonders if he caught a cold or something, noting that his body feels kind of sluggish.

Brushing it aside, Mahiro reaches for his tablet, then becomes further confused by the look of his hands, opening and closing his fist a few times to make sure it is his. He wonders if his hands were always this small, before brushing it off and grabbing the tablet.

As he lies on his back to use the tablet, Mahiro becomes confused to see an unfamiliar reflection in the tablet's screen. Deciding that something is definitely up, as his head feels funny as well, he stands up and places the tablet on his bookcase so he can use the camera on the tablet as a mirror. As he does so, his pants fall off revealing his boxers, and he steps out of the pants as he continues.

Mahiro yawns as he turns on the tablet, then becomes shocked and confused to see the face of a young girl staring back at him from the tablet's screen. He pulls on his face with his fingers to confirm that it is indeed himself that he's seeing, then does a few poses for the camera to confirm it. Letting out a few tears, Mahiro tells himself to pull it together, and confirms that he's Mahiro Oyama, an avid eroge gamer and self-sufficient home sucurity officer. He notes that his is supposed to be a young man in his prime. He further notes that this is crazy, but yells at the ceiling that it seems as if he's been turned into a girl.

Horrified, and knowing that there is only one way to know for sure, Mahiro starts to pull down his boxers to check his private area to confirm his theory. Nervously, he pulls down his boxers claiming that it is solely for science.

At that moment, Mahiro's younger sister Mihari comes in to say good morning to him, only to catch him with his boxers around his ankles. After a moment of awkward silence, Mihari begins to walk up to Mahiro. Mahiro feels embarrassed, claiming that it's not what it looks like. Instead of saying anything, Mihari examines Mahiro from all angles. She ends this by lifting up the front of his shirt to see his now exposed private area and seems satisfied, much to Mahiro's embarrassment. She remarks that it looks like "that" did the trick, and notes that she didn't expect that Mahiro would turn out looking so cute, noting that Mahiro is now around middle-school age.

Mahiro is puzzled, then looks over to a half-empty cola bottle he, now she, drank the previous night. Putting two and two together, she realizes that Mihari put something in her drink the previous night and asks her to confirm if she drugged her. Mihari confirms that she put a drop of something in Mahiro's drink, leading Mahiro to comment that she can't just treat people like guinea pigs.

Mahiro asks her what she takes her big brother for anyway. Being brutally honest, Mihari says that Mahiro is an unemployed, good-for-nothing shut-in, a nocturnal deadweight who hasn't left the house in two years, and someone who is addicted to those gross video games. All of these comments make Mahiro feel stabbed, and she collapses on the ground.

Mihari tells Mahiro that she thinks that it's time that she got a job. Mahiro asks how he could find work looking like this, and wonders if Mihari wants him to sell her new body. Mihari says "absolutely not" to that suggestion, and says that she just needs Mahiro to help her monitor her. She tells her to think of it like a clinical trial. She also tells her not to worry, as she'll go back to normal once the medicine is out of her system. She thinks that what's done is done, and suggests that Mahiro try enjoying life as a girl for a bit. As Mahiro ponders the suggestion, Mihari adds that as a start she could get up a little earlier and adopt a healthier lifestyle.

Mahiro starts to laugh at that suggestion. Going off of Mihari's suggestion that she enjoy herself, she decides to indulge in the greatest pleasure that life has to offer; eroge: girl edition. As she walks to her computer, she tells Mihari to scram as she knows where the door is. She notes that she shouldn't even be barging into his room in the first place.

Mihari gets a bit disgusted at the thought of the eroge game, but then smiles and decides to have some fun of her own. Walking up to where Mahiro is sitting, she whispers in Mahiro's ear that she'll let her in on a little secret. She says that apparently, the clitoral orgasm is 100 times more intense than the penile orgasm, which draws Mahiro's attention. Mihari warns Mahiro that if she rushes into this before she's ready, the experience might quite literally blow her mind. Mahiro's mind appears to get blown just at the idea of that. Having said everything she wanted to say, Mihari closes the door and leaves Mahiro to her own devices.

Turning back to her computer, Mahiro attempts to get aroused by what is on screen, but fails. Crying, she calls Mihari a scoundrel for taking away her source of pleasure.

Later in her room, Mahiro switches to playing an MMORPG using a female avatar. Grinning as her fingers fly across the keyboard, she notes that boy or girl she is still a machine; a monster-slaying machine. As she continues to play, she starts to feel uncomfortable and realizes that she has to pee. She also notes that the boss is about to spawn in the game any moment now, and doesn't want to miss it. Rocking back a forth a few times to try and take her mind off it, she notices an empty tea bottle on the edge of her table. Although she doesn't want to go that route, she decides that she has to do it for the game.

She ultimately decides that she can't do it and bursts out of her room, running to the bathroom. She slams the door behind her and quickly pulls down her boxers as she lifts the toilet seat up. She stands in her usual position to relieve herself, before remembering that she can't pee standing up anymore since she's a girl. She puts the toilet seat back down and sits down to pee, sighing with relief as she does so.

Strolling back to her room in disbelief, Mahiro closes her door, walks over to her bed, then collapses on it. She rolls around repeatedly, feeling so weirded out that she just did that. As she does, it is revealed that Mihari installed a hidden camera in a box on the top shelf. Watching the action unfold from her bedroom, Mihari sighs over the fact that Mahiro made some small progress.

Some time later, Mihari comes into Mahiro's room and asks her to show her her tummy as she holds out a stethoscope. Mahiro backs up slightly, saying that she's rather not do that sort of roleplay with her little sister, leading Mihari to angrily point out that she's doing a check-up.

Mahiro lifts up her shirt, and Mihari tells her to breathe in and out. Mahiro does, then asks if they have to do this every day. Mihari says that they do, for the time being. She tells Mahiro to turn around, and proceeds to repeat the process on Mahiro's back this time.

Before she can though, Mihari is overwhelmed by a foul stench that she says smells like wet dog, much to Mahiro's surprise. Turning Mahiro around and gripping her shoulders, she asks her when the last time she bathed. Mahiro tells her that it was roughly five days ago, and Mihari (offscreen) orders Mahiro to take a bath immediately.

In the bathroom, Mahiro stands in front of the mirror with her eyes shut. She notes that the time has finally come for her to see her new body. She opens her left eye, then shuts it in an instant and apologizes to the naked girl she sees in the mirror as she turns away and shuts her eyes again. Soon after, she wonders who she's apologizing too and wonders if she's lost it. Taking a deep breath, she decides to try again and be careful that she doesn't overstimulate herself.

Turning around, she looks at her reflection for the first time, all the while holding her right hand out in such a way that her bust and private area cannot be seen. Blushing, she notes that it is actually more lewd this way and starts to slowly lower her arm to uncover her private area.

As this is happening, Mihari comes into the bathroom and tells Mahiro that she is leaving a change of clothes by the sink. The sudden voice startles Mahiro, causing her to slip and fall on her back. Mihari asks what that was, also asking if Mahiro is okay. Mahiro is revealed to have slipped in such a way that her legs are above her head, giving her a full glimpse of her private area. She insists to Mihari that she is fine.

Mahiro turns on the shower, and sits on a stool as she washes her now long hair. As she does, she wonders what's gotten into her today. Staring at her reflection and then glancing down at her private area, she notes that there's nothing much to speak of there anyway.

Once she's finished, Mahiro comes out of the bath area and wipes her feet on the rug. She notes that taking a bath doesn't hurt every once in awhile, and begins to wonder where Mihari put her clothes.

Looking around, she only sees a set of girl's clothes and belives that Mihari must have left her own clothes there by mistake. Mahiro calls out to Mihari and asks about her clothes, and Mihari calls back that she already said that she left them right there. Mahiro is shocked by this, and glances at the panties that were left out for her, wondering if Mihari is really serious.

Mahiro gets changed into the new clothes, revealed to be a white sundress, and twirls around in it outside the bathroom feeling awkward and embarrassed. Mihari is overjoyed, noting that Mahiro is so incredibly cute. She notes that she always wanted a little sister to play dress up with, leading Mahiro to angrily point out that she is not Mihari's little sister. Mihari then flips up the front of the skirt of the dress, and is happy that Mahiro didn't skip the ladies underwear that she also left there. Embarrassed, Mahiro asks if this is going to be a regular thing.

As Mihari gets up, Mahiro notes that she doesn't feel right wearing such flimsy clothes, and says that she's getting changed right after this. Mihari tells Mahiro that she went ahead and put away all of Mahiro's old clothes for her, and says that she'll be arranging all of Mahiro's outfits from now on. Mahiro is shocked and confused, but Mihari points out that if she left her to her own devices she'd never get changed. Mahiro can't exactly disagree with that statement.

Mihari says that Mahiro will now be getting up early and getting dressed in the morning, remembering to wash her face and eat her breakfast, taking a bath every day and brushing her teeth before bed, adding that it's important to maintain a well-balanced routine. On top of this, she points out that Mahiro's old clothes probably don't fit anymore, and Mahiro reluctantly agrees.

Seeing how gloomy Mahiro is, Mihari gets behind Mahiro and asks her to look at herself in the mirror. After a moment, Mahiro does so and is amazed at how good she looks. Mihari says that Mahiro is so much cuter now, so she might as well dress up and show off a little. Mahiro, still amazed at her reflection, agrees with that statement.

As Mahiro continues to stare at her reflection, and lets out a giggle. Embarrassed and realizing what she just did, Mahiro turns around and claims that she's not into that stuff. She adds that wearing dainty clothes like this just weirds her out. Understanding, Mihari asks Mahiro if she wants to try something a little more conservative. After a moment of reflection, Mahiro decides that maybe she can put up with this just for today, and walks upstairs towards her room. Mihari watches her, and smiles.

The next day, as promised, Mihari leaves a change of clothes outside Mahiro's door. With them is a note which reads "Here's your outfit for today. Mihari". Mahiro opens her door, reads the notes, then brings the outfit into her room.

Stripping off her jacket and pants, Mahiro slips into the outfit which consists of a ruffled pink top, a pale pink skirt, and white lacy ankle socks. After putting them on, she can't help but twirl a bit as she admires her reflection in the mirror.

Her joy ends though as she sees Mihari reflected in the mirror, amazed at how much Mahiro is enjoying herself. Upon seeing her, Mahiro lets out a piercing scream.

Sometime later, Mahiro is seen crying at her computer. Mihari comes in and sees this, then asks Mahiro what's wrong and what's got her down this time. Mahiro tells Mihari that she's reached her breaking point, and that she doesn't think that she can stand the no-fap life much longer. She mentions how she was desperate to suppress the urge, so she tried playing the BL (Boy Love) game that she accidently bought once. Much to her horror though, she got a little turned on by it. Mihari just sighs at this.

Mahiro says that she never thought that this day would come, though Mihari tries to comfort Mahiro by pointing out that this is perfectly normal as she's a girl now and that it might just come with the territory. Mahiro angrily yells that she refuses to accept this, before going back to crying.

Mihari wonders to herself if the treatment has begun to alter Mahiro's tastes, thinking that it seems that she likes the girly outfits more than she lets on as well. Seeing a nearby copy of Anime Sports Edition on the floor, Mihari gets an idea. Putting her hand on Mahiro's shoulder, Mihari tells her that if she's up for it, she knows just the thing that'll clear her head. Mahiro gets intrigued, but also a bit confused.

It turns out that Mihari's idea was to go out for a run to get in some exercise. Mahiro is vehemently opposed to the idea and desperately tries to avoid leaving the comfort of her front porch, claiming that she wouldn't do this in a million years. Mihari drags Mahiro off the porch, despite Mahiro's struggles to hold on.

Characters

 * Mahiro Oyama
 * Mihari Oyama
 * Kaede Hozuki
 * Hiyori Yosaki

Trivia

 * First appearances in the anime of Mahiro Oyama, Mihari Oyama, and Hiyori Yosaki, though the latter isn't given a name and is only credited as "clerk".
 * If you look closely during the flashback to Mihari's time in middle school, you can see the names of some of her classmates that ended up ranking below her in the first semester final exams. They are as follows: #2 - Mai Katō (加藤 まい, Katō Mai), #3 - Sōta Koroda (黒田 そうた, Koroda Sōta), #4 - Aika Honma (本間 あいか, Honma Aika), #5 - Shoma Aoyagi (青柳 しょうま, Aoyagi Shoma), #6 - Nami Kobayashi (小林 なみ, Kobayashi Nami), #11 - Ai Itō (伊藤 あい, Itō Ai), #12 - Yūya Kitade (北出 ゆうや, Kitade Yūya), #13 - Daisuke Okuda (奥田 だいすけ, Okuda Daisuke), #14 - Ren Miura (三浦 れん, Miura Ren), #15 - Kazuya Harada (原田 かずや, Harada Kazuya), and #16 - Takuya Shirai (白井 たくや, Shirai Takuya).