S01E01 Mahiro's Confusing New Body
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...
ONIMAI: I'm Now Your Sister!
S01E06: Mahiro Goes Back to Middle School
Momiji shows up at Mahiro's house with her two classmates, Asahi Ohka and Miyo Murosaki, to invite him out for parfaits.
Overview
When lazy, erotic-game loving Mahiro Oyama is transformed into a girl by his younger scientist sister's experiments, he becomes determined to change back, only to recognize that with his new opportunity, he may want to turn his life around.
Episodes
S01E02 Mahiro's Time of the Month
As Mahiro stumbles through his new life as a girl, he finds himself gradually beginning to get into the swing of things. Realizing this, however, prompts him to try and reclaim some of his masculinity....
S01E03 Mahiro's Close Encounter
Mahiro makes a mad dash for the bathroom, but when he opens the door, he finds the facilities are already occupied by a high school girl he's never met. This bold fashionista turns out to...
S01E04 Mahiro's New Friend
Mahiro loses to Mihari in a video game, so he has to do the grocery shopping this week as punishment. As an unemployed, good-for-nothing shut-in, the task at hand is daunting, but he plucks up...
S01E05 Mahiro Discovers Adventure and Social Gatherings
In a rare turn of events, Mihari wakes up one morning to find Mahiro has gotten up before her. Since the corner store was going to start selling clear files from his favorite anime that...
S01E06 Mahiro Goes Back to Middle School
Momiji shows up at Mahiro's house with her two classmates, Asahi Ohka and Miyo Murosaki, to invite him out for parfaits.
S01E07 Mahiro's Role-Playing Game
Just when Mahiro is beginning to get used to middle school life again, finals are upon them. Despite his initial blasé attitude, Mahiro finds himself reluctantly handing in a 80% blank answer sheet after having...
S01E08 Mahiro's First Girls Sleepover
It's finally winter break and Mahiro is excited to get into his Winter Vacation Mode. Unbeknownst to him, however, Mihari invites Momiji and the others over for a sleepover. She hopes this will prevent a...
S01E09 Mahiro Rings in the New Year
It's Christmas and Mahiro is shocked to hear his own little sister has a date. Unable to shake his unease, he follows her through the festive hustle and bustle in secret, with Momiji as his...
S01E10 Mahiro Ponders Boobs and Identity
It's the start of the third semester and winter uniforms are now in effect. For Mahiro and the girls at school, this means braving the cold winter air in mandatory skirts. Who knows how Miyo...
S01E11 Mahiro Pretties Up
Horoscopes are all the rage at school right now, and Mahiro is curious to see what all the fuss about. According to his forecast, an important occasion is on the horizon and he may be...
S01E12 Mahiro's Future as a Sister
Mahiro and the girls take a trip to a Japanese inn over spring break. First they hit the town in their yukata, before heading to the open-air bath to detox. However, things go south when...
Cast
Marika Kouno
Mahiro Oyama (voice)
Kaori Ishihara
Mihari Oyama (voice)
Hisako Kanemoto
Kaede Hozuki (voice)
Minami Tsuda
Momiji Hozuki (voice)
Kana Yuuki
Asahi Ohka (voice)
Natsumi Hioka
Miyo Murosaki (voice)
