Mahiro and Visitation Day

Mahiro and Visitation Day (まひろと授業参観, Mahiro To Jugyō Sankan) is Chapter 48 of Onimai: I'm Now Your Sister!. It was originally published on Pixiv on January 30, 2021.

Summary
Mahiro and her classmates endure Parent Visitation Day.

Plot
In Class 2-B, Mari announces that Parent Visitation Day is coming up, and tells the students to make sure to give their parent or guardian the infosheet so they can be ready for their visit next week.

Mahiro dreads Parent Visitation Day, and thinks to herself that maybe she shouldn't tell Mihari. Momiji also notes that she hates Visitation Day, and Miyo agrees that it is so embarrassing. Nayuta on the other hand thinks that it might be fun, and hopes her "onee-san" will come. Mahiro suddenly remembers Nayuta mentioning this previously and starts to wonder about it.

On the day of Parent Visitation Day, Mahiro throws the handout in the trash, feeling proud of herself for keeping it a secret from Mihari. Mahiro heads off to school in a hurry and unusually happy, causing Mihari to get suspicious. She brushes it off though and decides that it's time to get some tidying done. In the trash, she finds the crumpled up handout and opens it up, wondering what it is.

At school, the parents of most of the students fill out the classroom for Parent Visitation Day. Momiji is glad that her mom didn't make a scene, and Miyo adds that she knows better not to stand out. Mahiro realizes that she's never met Momiji's mom before and asks which one she is, though Momiji tells Mahiro not to go looking. Mahiro sees Asahi and her mother, and it takes her back to the nervous tension associated with this event which being pleased and embarrassed at the same time. Mahiro relaxes though, as she gets to observe from a position of safety, imaging herself as royalty sitting on a throne.

Nayuta on the other hand is all gloomy, saying that she supposed it was bound to happen that her "onee-chan" was too busy to come. Mahiro's guilt over feeling good stabs her right through the chest upon hearing this. Asahi asks Mahiro if her guardian didn't show up, and Mahiro lies saying that something came up, though the guilt over lying to her friend stabs her multiple times.

At that moment, Mihari shows up and Asahi points her out, much to Mahiro's surprise. The other mothers are surprised to see Mihari, which causes her to nervously wave at Mahiro and chuckle. Mahiro is left feeling completely embarrassed, pointing out that Mihari should've at leats left the lab coat at home. Mihari realizes this and apologizes, claiming that she was in a hurry and forgot.

Mari comes in and tells everyone to find their seats, announcing that class is about to begin. She eventually calls on Mahiro, causing Mahiro to shriek. Mahiro reads a passage from an epic poem as part of her Literature II book in front of everyone, feeling completely embarrassed and causing Mihari to giggle at Mahiro's unbridled shame.

As Visitation Day continues, Chitose shows up and waves to Nayuta, causing her to becomes happy that Chitose was able to make it after all.

Eventually, the final bell rings and Mari announces that that is all for today, thanking all the parents and guardians in attendance.

At her desk, Mahiro pouts and calls Mihari a dummy for showing up like that. Mihari brushes it off and points out to Mahiro that she did say she was sorry. Mrs. Hozuki recognizes Mihari, and the two reconnect having not seen each other for a long time. Mahiro is amazed that all the mothers, including Mihari, are talking.

A voice calls it a thoroughly domestic display, and Mahiro agrees. Mahiro then realizes that she was speaking to a stranger and hides behind a curtain asking who's there. It turns out to be Chitose, who Nayuta introduces as her "onee-san", and Chitose points out that Mahiro met her at the health screening. Mahiro also recognizes that Chitose is the lady on the sticker that Mihari offered to her. Mihari turns around and is surprised to see Chitose there, and is equally surprised that she's personally met Mahiro and has a relative in the form of Nayuta.

Mihari starts to wonder if Nayuta is Chitose's daughter and gets shocked, though Chitose points out that she is not that old yet. She says that Nayuta is someone that she's looking after. Nayuta claims to be Chitose's assistant, though Chitose contradicts that statement by saying that only Nayuta thinks that. Mihari finally remembers that she's seen Nayuta at the university before, and Chitose confirms that Nayuta sometimes spends her time there. Mihari tells Chitose that she has to tell her these things, while Chitose points out that she likes surprises.

Mahiro sighs with relief that all these mysteries are solved, and asks Nayuta to confirm that she is just a regular middle-schooler. Nayuta says that she doesn't know about that and chuckles, leading Mahiro to cringe at Nayuta being so cryptic. Chitose laughs and tells Mahiro that she hopes that she and Nayuta can continue being good friends, and Mahiro agrees, causing Nayuta to smile.

Back at home, Mihari explains that Chitose is her senpai, and that she might be a little flighty, but pretty amazing too. Mihari adds that she was only able to perfect the feminization drug with Chitose's assistance. Mahiro is shocked, realizing that Chitose is the mastermind behind all this. Mahiro says that she can't help feel like Chitose is hiding something, and Mihari agrees, saying that knowing Chitose makes that a distinct possibility. Mahiro comments that Mihari's whole research lab is like an evil secret society, but Mihari laughs it off and says that it's an accredited university research program.

A full shot of Miyo's mom next to her daughter is then revealed.

Characters

 * Mahiro Oyama
 * Mihari Oyama
 * Momiji Hozuki
 * Asahi Ōka
 * Miyo Murosaki
 * Nayuta Tenkawa
 * Mari Nishinomiya
 * Aoi Tachikawa
 * Yuta Sakurada
 * Minato Senkawa
 * Nemu Fujimi
 * Kasumi Hozuki
 * Yu Ōka
 * Yomi Murosaki
 * Chitose Azuma

Trivia

 * First appearances of Kasumi Hozuki and Yomi Murosaki.
 * Mahiro references the first time that Nayuta mentioned her "onee-san" in "Mahiro and the Sticker Collection".
 * As noted by the chapter, the sentence that Mahiro reads is a passage from the Tosa Nikki by tenth century poet Ki no Tsurayaki. The entirety of the passage that Mahiro was reading goes as follows: "It is generally a man who writes that which is called a diary, but now a woman will see what she can do."
 * Chitose references when she performed Mahiro's school physical in "Mahiro and the School Physical".
 * Mahiro recognizes Chitose as the unknown lady on the sticker that Mihari tried to give her in "Mahiro and the Sticker Collection".
 * Mihari finally remembers where she saw Nayuta, having previously tried to remember in "Mahiro and the Barbecue Secret".