One day, a nephew who is a student preparing for entrance exams came to Tokyo from his father's hometown to stay with a couple living in the city. The couple gladly welcomed the nephew, who wanted to board with them to focus on his exams. Chitose is a busty housewife with a kind, caring personality who is terrible at saying no. The frustrated virgin student, currently at the peak of his sexual desire, couldn't stop staring with inappropriate, panting eyes at the plump, explosive breasts of his "Tokyo Aunt." Then, a few days later, on a night when the husband was away for work, a forbidden sex session to take his virginity takes place...!