“Riho”, a high school student who came to Tokyo to take an examination in Tokyo. In the meantime, the recipient is the Kimura family, a relative of Riho. The “Kimura family” has a dull son named “Ichiro”, but he does not study every day and just masturbates with chewy, and there is no sign that his academic ability will improve. Such “Riho” and “Ichiro” reunite for the first time in about 10 years, but … Sisters who have grown into amazing huge breasts within a while. “Ichiro”, who remembered that he used to take a bath and sleep together, sent a keen eye to “Riho”‘s boobs.