Nagisa, a girl in her growth period. One day, she entered her brother's room and found an erotic book he had forgotten to put away... "Big brother, do you like girls' breasts?" Nagisa shows her breasts to her brother who has returned to the room. Her innocent act causes her brother's reason to collapse completely. The perverted older brother thoroughly caresses his pure, easily overwhelmed younger sister's body!! This is a secret record of siblings growing up together in lewdness...
