Mahiro's Exciting Weekend

Mahiro's Excting Weekend (まひろと楽しい週末, Mahiro To Tanoshii Shuumatsu) is Chapter 23 of Onimai: I'm Now Your Sister!. It was originally published on Pixiv on December 29, 2018.

Summary
Mihari invites Kaede and Momiji over for lunch.

Plot
Mahiro is sitting on the couch smiling. Mihari tells her that she seems upbeat today, and Mahiro says that she should be as today is the start of her long-awaited weekend. She continues by saying that it's been so long since she let herself wallow in laziness. Mihari considers saying something, but decides to let it go since Mahiro did go to school every day, which is a lot for him. The doorbell rings, and Mihari notes that "she's" here. Opening the door, it turns out to be Kaede and Momiji.

Mihari is surprised the Momiji came as well, having invited Kaede over. Momiji asks if Mahiro is home, and Mahiro tells her yes, mentioning that Mahiro is taking it easy today. Mihari leads the two girls into the living room where she tells Mahiro to pardon the intrusion. Mahiro becomes uneasy and hides behind the couch, asking why there are so many people here. Kaede laugh and tells Mahiro that it's nothing bad and holds up a bag. She says that she thought that Mahiro might want to have lunch together with all of them, and Mahiro's spirits lift instantly.

While Mihari and Kaede get lunch ready in the kitchen, Mahiro and Momiji hang out in the living room. Mahiro beams, noting that keade's cooking will make a great day off even better. Mahiro suggests to Momiji that they play a video game while they wait, but Momiji asks Mahiro if she's been keeping up with her homework. Momiji says that there is a lot of stuff due next week and since Mahiro was late starting she thought that they could do it together. Mahiro is shocked that she overlooked something like that, but ultimately realizes that she has to do it and accepts Momiji's offer.

In Mahiro's room, Momiji suggests that they get math out of the way first, while Mahiro thinks to herself that this is a nightmare. As she takes out her math textbook, Mahiro thinks to herself how Mihari lied when she said that she wouldn't need to study. Mahiro asks if she can just copy Momiji's answers. Momiji says no to that, and Mahiro laughs saying that she had to ask.

Mahiro notes that since she has no choice, she may as well get cracking on it, starting from question three in the textbook. Mahiro becomes surprised at something, while Momiji complains about math, saying that she loses it whenever she sees an x. Momiji then notices that Mahiro's hand isn't moving, and Mahiro struggles to formulate an answer to that. Momiji thinks that Mahiro got stuck and looks over to see where it happened. She instead becomes shocked that Mahiro has already finished all of the problems, with Mahiro thinking to herself that it is just middle-school math. She adds that she might be out of practice, but this stuff at least is cake. Momiji demands to know how Mahiro did that, and Mahiro claims that Mihari tutored her while she had to stay home from school. Momiji accepts the explanation, noting that Mihari is like a doctor or something. Mahiro laughs at that, imaging Mihari as a doctor with a pair of glasses.

Mahiro also remembers that she didn't have bad grades herself the first time that she was in middle school. Mahiro then notices that Momiji got one problem wrong and shows her what she did wrong. Momiji loses it, feeling embarrassed over the fact that she was supposed to be teaching Mahiro but instead Mahiro is teaching her. Mahiro apologizes for that.

Late on, the four girls have eaten and Mahiro thanks Kaede for the meal, saying that she's stuffed. Kaede notes that Mahiro and Momiji are in a good mood, and Momiji tells her that the two got all the homework done quickly. Mihari si overjoyed that Mahiro apparently did homework and rubs the sides of Mahiro's head calling her a a good girl, despite Mahiro's protests. Mahiro notes that she didn't even think about this, and at this rate she might ace all of her exams. She likens herself to an overpowered isekai character and chuckles while saying that she's really looking forward to this upcoming test. Mihari becomes alarmed that Mahiro said something like that and asks if she's okay and if they need to go the ER. Mahiro is left silent at that remark while Momiji laughs at it.

Later on, Mahiro watches TV, being amazed that the weekend is already over.

Characters

 * Mahiro Oyama
 * Mihari Oyama
 * Kaede Hozuki
 * Momiji Hozuki

Trivia

 * Mahiro references when Mihari told her that she didn't need to study in "Mahiro's First Day".