Onii-chan wa Oshimai!

Mahiro's Bewildering New Body

Mahiro struggles with his new female identity and attempts to reclaim masculinity.

Mahiro gradually adapts to his new life as a girl, which prompts him to attempt reclaiming his masculinity. He tries to engage his core and perform a sit-up, but this futile effort results in a stomachache. Mihari observes his condition worsening rapidly and experiences an epiphany. She realizes that his pain is likely connected to the fact that almost a month has passed since Mahiro turned into a girl. The episode focuses on Mahiro's physical discomfort and Mihari's dawning understanding of his situation as he navigates these changes.

Mahiro encounters Kaede, Mihari's former middle school classmate, in the bathroom.

Mahiro rushes to the bathroom only to find it occupied by Kaede, a bold high school girl and Mihari's old classmate. Initially nervous, Mahiro grows attached to her as he discovers her kind nature. The situation shifts abruptly when Kaede asks if he has never done it before and moves closer to the confused Mahiro, leaving his next steps uncertain.

Mahiro makes a new friend

Mahiro Discovers Adventure and Social Gatherings

Mahiro Returns to Middle School

Mahiro's Role-Playing Game

Mahiro hosts his initial sleepover with female friends

Mahiro welcomes the New Year

Mahiro contemplates breasts and identity as winter uniforms arrive

The third semester begins with the implementation of winter uniforms, requiring Mahiro and the female students to endure the cold air while wearing mandatory skirts. This seasonal change introduces new social dynamics, particularly regarding how Miyo will respond to the sight of Mahiro and Momiji appearing together in matching scarves. The narrative focuses on these immediate environmental shifts and the resulting interpersonal reactions among the characters as they navigate the start of the new term.

Mahiro investigates the school's horoscope trend and anticipates a significant upcoming event.

Horoscopes have become a popular topic among students at school, prompting Mahiro to investigate the widespread interest. He checks his own forecast, which predicts that an important occasion is approaching and may bring unexpected surprises. Mahiro attempts to determine what specific event the prediction refers to, seeking clarity on the mysterious forecast that suggests a notable change or revelation is imminent for him.

Mahiro's Future as a Sister