In Tokyo, our protagonist lives alone in a cramped one-room apartment. Suddenly, his younger sister Sakura moves in, starting a sudden cohabitation! As she grows up, her voluptuous breasts are always causing him trouble. Unable to resist any longer, he forcefully takes what he wants. To his surprise, Sakura then asks for a creampie sex! Our brother and sister find themselves in a taboo relationship that they can't share with anyone else... *The contents may vary depending on the distribution method.