Sakura Manabe is a 16-year-old high school student and is living with her 12-year-old sister Momiji and 27-year-old sister Botan, who works to support the three of them. Their 19-year-old brother Kashiwa has been away at college for two years and has suddenly decided to come back to live with them. However, when Kashiwa arrives, Sakura and the others discover that Kashiwa has now decided to live as a woman. Sakura and her two sisters now have to cope with the new reality of having another sister.