Mahiro and the Secret Garden

Mahiro and the Secret Garden (まひろと秘密の花園, Mahiro To Himitsu No Hanazono) is Chapter 6 of Onimai: I'm Now Your Sister. It was originally published on Pixiv on July 29, 2017.

Summary
Mahiro and Mahari head to a public bath after their water heater breaks.

Plot
Mihari has prepared a bath for herself, singing about how warm and relaxing it will be. When she puts her hand in the water to test it she becomes shocked to find that its freezing. Confused, she tries fiddling with the water heater by the tub.

She tells Mahiro who is playing a video game. Mahiro asks her if she can fix it as she is a science person. Mihari says that she is science person, but not an engineering person. Mahiro rejoices over there not being any baths today, though Mihari immediately says that there is no chance of that. She asks Mahiro is there is a public bathhouse near there, to which Mahiro confirms that it is across from the liquor store.

Mahiro then asks if that is a bad idea, to which Mihari is confused. Mahiro points out that it would be her, in a woman's bath. Mihari asks what's wrong with that, as she is a girl now, leading Mahiro to be amazed that she's okay with this. Mahiro weights how Mihari feels about public vs privacy as a hard-core privacy enthusiast herself, with public ultimately winning out.

At the woman's bath, Mahiro is surprised to find it full of older women, one of which greets the two of them. Mahiro exclaims that she knew this would happen, and Mihari says that it too bad for Mahiro. Mahiro remarks that she doesn't care if anyone here sees her naked, but asks if Mihari feels the same way. Mihari asks what she means, and then realizes that she was half undressed already in front of Mahiro. She quickly covers up telling Mahiro not to look at her like that, but Mahiro tells to relax saying that she's not into incest. Mihari is still left feeling a bit weird.

In the bath, Mahiro is amazed by how large it is and is quickly drawn to the jacuzzi jets, leading Mihari to tell her to be serious and wash up first. The two siblings wash up, and Mahiro finishes quickly and begins to walk away. Mihari tells her to get back here, which confuses Mahiro as she already washed. Mihari tells her that she can't get away with that anymore as she has long hair now. She remarks that it is time that she taught Mahiro how to take care for herself.

She begins to wash Mahiro's hair, telling her first brush it out under the stream of water to rinse. After that, to work up a nice lather with the shampoo and gently massage it in. Finally, to thoroughly rise out the shampoo which should take five minutes, much to Mahiro's disbelief. She then says to apply product to the ends, to which Mahiro refuses and begs her to stop. In the tub, she tells Mahiro to remember above all that she shouldn't soak her hair in the tub as she'll damage it. With this, Mahiro decides that she has had enough and walks out of the bath, much to Mihari's surprise. She tells Mihari that she'll wait for her in the lobby, leading Mihari to submerge part of her face beneath the water, all the while Mihari thinks to herself that she was just trying to help.

In the lobby, Mahiro enjoys a bottled latte drink she bought and sighs, remarking that she guesses that this is the reason why girl's take so long in the bath. She then smiles thinking to herself that she never could've imagine that she would ever bathe with Mihari again after so long. She remembers how when they were kids they used to bathe together all the time where she used to help Mihari much in the same way that Mihari helped her today. She notes that now its the other way around. She also notes that Mihari has grown a lot since then too in a lot of ways, and that it's hard to think of her to think of Mihari as her little sister anymore.

Mihari soon after comes into the lobby and calls out for Mahiro, referring to her by her first name rather than "onii-chan". Mihari notices her and apologizes for keeping her waiting. Mahiro is confused by her calling her by her first name, and Mihari points out that she can't call her "onii-chan" since there are other people around. Mahiro admits that that is true, and suggests that they head home, playfully referring to her as "onee-chan" (the female equivalent of "onii-chan" which is used to refer to an older sister).

Mihari immediately becomes overjoyed by hearing Mahiro call her that and starts to chuckle diabolically, though Mahiro insists that she was just following Mihari's lead. Mihari begins cuddling Mahiro in a loving fashion saying that they should do this more often, though Mahiro tells her to stop. Mihari notices that Mahiro's hair isn't dried yet, and decides to show Mahiro how to dry it properly because "after all [she's her] onee-chan after all", which caused Mahiro to beg her "no more".

At home Mihari shows Mahiro how to dry her hair, telling her to protect it with a towel while drying it with a hairdryer.

Characters

 * Mahiro Oyama
 * Mihari Oyama

Trivia

 * According to the sign behind the receptionist's desk, the public bath costs 380¥ ($2.94 USD) for Adults and 190¥ ($1.94 USD) for children.