One day, Oyama Shinhiro, a stay-at-home dependent, woke up and found himself turned into a "girl"! ? Just when Shinhiro didn't know that the beautiful girl in the mirror was himself and was confused, his scientist sister Oyama Minami appeared. She revealed that she added a strange drug to the drink! Shinhiro has been crazy about staying at home and playing small yellow games for the past two years, and occasionally works when he has to! Shinhiro, who suddenly became a girl and started his life, has no idea about women's lives such as toilets, bathrooms, skirts, bras, etc.... And he knows Minami's junior high school classmate Hozuki Kaede and her sister Hozuki Kaede. Shinhiro's daily life gradually becomes lively. In the continued suffering, what will be the fate of the "former" brother...!