'Ayumi' of the university student causes 'Kenji' of the boyfriend during the trip of parents in a house. And begin Sex so that be not noticed 'Maakun' of the younger brother, but be found on the way, and the Maakun misunderstands it more when Elderly Sister is tormented simply because there is not knowledge of the Sei. The Ayumi set up a body by oneself, and performed sex education to tell Mami to an important younger brother.
