Mahiro's Confusing New Body Mahiro Oyama is a hikikomori living with his grade-skipping wunderkind little sister Mihari who is a researcher. One day he wakes up as a young girl after being drugged by Mihari, as a part of her Big Brother Rehabilitation project. She forces him to take a shower and wear feminine clothes upon a health checkup. Seeing him obsess over his newfound interest in a yaoi visual novel, she takes him out for a jog and buys him a new bra; he refused to have one on for the jog in an attempt to hang onto his ever-decreasing masculinity.